SEARCH · PubMed Health

Results for “hyperprolactinemia”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources

PubMed2000

The dominant role of increased intrasellar pressure in the pathogenesis of hypopituitarism, hyperprolactinemia, and headaches in patients with pituitary adenomas.

Mild hyperprolactinemia frequently accompanies the hypopituitarism seen in patients with pituitary macroadenomas that do not secrete PRL. Recent data suggested that the hypopituitarism and mild hyperprolactinemia in this setting are largely due to compression of pituitary stalk and portal vessels. Headaches (HAs) are frequently seen in patients with large adenomas and at times in those with microadenomas. Because the walls of the sella turcica are relatively rigid, we postulate that tumor growth within the sella increases intrasellar pressure (ISP), which in turn impairs portal blood flow, resulting in mild hyperprolactinemia and hypopituitarism. We also postulate that increased mean ISP (MISP) contributes to the development of HAs. Normal MISP is not known but is unlikely to exceed normal intracranial pressure of less than 10-15 mm Hg. We determined MISP in 49 patients who had transsphenoidal surgery for pituitary adenomas. MISP was measured using a commonly available intracranial monitoring kit where a fiberoptic transducer was inserted through a 2-mm dural incision at the time of adenomectomy. Patients with deficient FSH, LH, ACTH, or TSH secretion were considered hypopituitary. Data on serum PRL levels were included for analysis only in patients whose adenomas had negative immunostaining for the hormone. MISP measurements ranged from 7-56 mm Hg, with a mean (+/-SD) of 28.8 +/- 13.5 and a median of 26 mm Hg. The pressure measurements were higher in patients with hypopituitarism than in those with normal pituitary function (P = 4.6013 x 10(-6)). Patients presenting with HAs had higher MISP than those who did not (P = 5.44 x 10(-7)), regardless of their pituitary function or tumor sizes. PRL levels correlated positively with MISP values (r = 0.715, P < 0.0001). Tumor size did not correlate with MISP or PRL levels. The findings of increased MISP in hypopituitary patients and the documented correlation with PRL levels, suggest that ISP is a major mechanism involved in the pathogenesis of hypopituitarism and hyperprolactinemia. Similarly, the increased MISP in patients with HAs, irrespective of tumor size or pituitary function, suggest that increased ISP is a major mechanism involved in the pathogenesis of this symptom. The data support the hypothesis that in patients with pituitary adenomas increased ISP is a major mechanism contributing to the development of hyperprolactinemia, hypopituitarism, and HAs. Increased ISP in these patients leads to compression of the portal vessels and the associated interruption of the delivery of hypothalamic hormones to the anterior pituitary. This would explain the reversibility of pituitary function observed in most patients after adenomectomy. However, increased ISP may also lead to decreased blood supply, resulting in ischemic necrosis in some regions of the pituitary. The latter could limit potential recovery of pituitary function after adenomectomy.

Adenoma↗

PubMed2001

Resistance to cabergoline as compared with bromocriptine in hyperprolactinemia: prevalence, clinical definition, and therapeutic strategy.

To evaluate the prevalence of resistance to cabergoline treatment, we studied 120 consecutive de novo patients (56 macroadenoma, 60 microadenoma, 4 nontumoral hyperprolactinemia) treated with cabergoline (CAB) compared with 87 consecutive de novo patients (28 macroadenoma, 44 microadenoma, 15 nontumoral hyperprolactinemia) treated with bromocriptine (BRC) for 24 months. Resistance was evaluated as inability to normalize serum PRL levels (first end point) and to induce tumor shrinkage (second end point). After 24 months, PRL normalization and tumor shrinkage after CAB and BRC treatments, respectively, were obtained in 82.1% and 46.4% of macroprolactinomas (P < 0.001) and in 90% vs. 56.8% of microprolactinomas (P < 0.001). The median doses of CAB and BRC able to fulfill the two criteria of treatment success were 1 mg/wk and 7.5 mg/d in macroprolactinomas, 1 mg/wk and 5 mg/d in microprolactinomas, and 0.5 mg/wk and 3.75 mg/d in nontumoral hyperprolactinemia. Hyperprolactinemia persisted in 17.8% of macroprolactinomas, 10% of microprolactinomas, and after CAB at doses of 5-7 mg/wk and in 53.6% of macroprolactinomas, 43.2% of microprolactinomas, and 20% of nontumoral hyperprolactinemic patients, after BRC at doses of 15-20 mg/d. In these resistant macro- and microprolactinomas, the maximal tumor diameter was reduced by 43.7 +/- 3.6% and 22.1 +/- 3.7% and by 59.3 +/- 7.1% and 4.3 +/- 2.1% after CAB and BRC, respectively (P < 0.001). In conclusion, long-term CAB treatment induced the successful control of hyperprolactinemia associated with tumor shrinkage in a higher proportion of patients than did BRC treatment. In a small number of patients (i.e. 17.8% of macroprolactinomas and 10% of microprolactinomas), however, CAB treatment did not normalize serum PRL levels despite reducing tumor mass, even at very high doses. Therefore, an absence of tumor shrinkage cannot be considered as end point to indicate resistance to CAB, and increasing the dose of CAB higher than 3 mg/wk does not seem to be helpful in controlling PRL hypersecretion.

Adenoma↗

PubMed2003

Gender differences in the prevalence, clinical features and response to cabergoline in hyperprolactinemia.

BACKGROUND: Gender differences in tumor size are supposed to exist in hyperprolactinemia since microadenomas are more commonly found in women and macroadenomas in men. Whether this reflects only a delay in diagnosis in men or a true gender difference in tumor pathogenesis is still unclear. OBJECTIVE: To prospectively analyze gender differences in the presentation and response to cabergoline treatment in 219 consecutive newly diagnosed patients with hyperprolactinemia. DESIGN: An open prospective design. SUBJECTS: Of the 219 patients of which 145 were women; 107 patients had macroprolactinoma, 97 had microprolactinoma, and 15 had non-tumoral hyperprolactinemia. METHODS: Presenting clinical symptoms, prolactin levels and tumor size at magnetic resonance imaging were measured before and 3-6 Months after cabergoline therapy. RESULTS: Prevalence of microprolactinomas (56% vs 22%, P=<0.0001) and non-tumoral hyperprolactinemia (10% vs 0%, P=0.01) was higher in women than in men. Men and women were of similar age (median 32 vs 29 Years; P=0.2) and a similar number had gonadal/sexual dysfunction (85 vs 83%, P=0.6); weight gain (70 vs 46%; P=<0.0001) and galactorrhea (52 vs 19%; P=<0.0001) were more common in women. Prolactin levels were higher in men than in women, whether exhibiting macro- (2848+/-2954 vs 1132+/-2351 microg/l, P=<0.0001) or microadenomas (187.8+/-51.8 vs 135.4+/-60.5 microg/l, P=0.009) and the size of the adenoma was larger in men than in women irrespective of macro- (25.8+/-12.4 vs 17.2+/-7.2 mm, P=<0.0001) or microadenoma diagnosis (8.0+/-1.4 vs 7.1+/-1.6 mm, P=0.04). After treatment, prolactin levels decreased by 89.2-96.4% in all groups, and normalized more frequently in micro- than in macroadenoma patients (86 vs 64%, P<0.0001), regardless of gender (70% vs 69%, P=0.9). Menses resumed in 82% of women, libido disturbances improved in 57% of men. Tumor size was reduced by 45+/-25% and 52+/-24% in macroprolactinoma patients and by 44+/-31 and 38+/-29% in microprolactinoma patients in women and men respectively. Visual field defects disappeared in 61% of women and in 71% of men (P=0.6). CONCLUSIONS: Prevalence of macroprolactinomas was similar in men and women; microprolactinomas and non-tumoral hyperprolactinemia were more frequent in women. Clinical symptoms at presentation differed according to gender, with galactorrhea and weight gain more frequent in women. The successful response to cabergoline treatment for 6 Months was higher in micro- than in macroprolactinoma patients and was similar in women and men.

Adolescent↗

PubMed2004

Prevalence of hyperprolactinemia in schizophrenia: association with typical and atypical antipsychotic treatment.

OBJECTIVE: To evaluate the prevalence and severity of hyperprolactinemia among a large sample of patients with schizophrenia and related psychotic disorders treated with typical and atypical antipsychotic medications. METHOD: Three electronic databases (general medical, psychiatric, and pharmacologic) containing the census data from November 2002 through March 2003 for a state-funded, inpatient hospital serving the chronically mentally ill were merged (N = 470). This database was purged of patient names, while the unique hospital identification number and demographic variables in each record were retained. These records were then screened to exclude patients with medications (except neuroleptics) or medical conditions known to elevate or suppress prolactin, leaving an overall sample (N = 422) in which to evaluate the prevalence of hyperprolactinemia. The sample was composed of patients with DSM-IV schizophrenia (N = 213), other related psychotic disorders (N = 131), mood disorders (N = 44), and other disorders (N = 34). RESULTS: For the overall sample (N = 422), which combined men and women, the mean serum prolactin level was 41.5 ng/mL; 290 of 422 patients were above the normal range. For women (N = 133), the mean serum prolactin level was 57.9 ng/mL, and 67% had levels above normal. For men (N = 289), the mean level was 33.9 ng/mL, with a 70% prevalence of hyperprolactinemia. While age did not influence the prevalence of elevated prolactin among men, age (reflecting reproductive status) was a significant variable in women; older age was associated with lower prolactin levels. For the study sample, a highly significant correlation was observed between neuroleptic dose (chlorpromazine equivalent) and serum prolactin level; however, this relationship was not determined on a medication-by-medication basis. Medications known to elevate prolactin were associated with higher prevalence rates of hyperprolactinemia, and "prolactin-sparing" medications had lower prevalence rates. However, when they were used in combination, the prolactin-elevating medication overwhelmed the effects of prolactin-sparing medication. CONCLUSIONS: This study suggested that neuroleptic treatment of schizophrenia is strongly associated with hyperprolactinemia and showed important differences between prolactin-sparing and prolactin-elevating medications.

Adult↗

PubMedDate not supplied

Development of a macroprolactinoma in association with hormone replacement therapy in a perimenopausal woman with presumed idiopathic hyperprolactinemia.

OBJECTIVE: To describe a 48-year-old woman with presumed idiopathic hyperprolactinemia, who was found to have a macroprolactinoma after receiving hormone replacement therapy for almost 3 years. METHODS: We present a detailed case report, including a chronologic summary of clinical and laboratory findings as well as the drug history of our patient. The related literature is also reviewed. RESULTS: Premenopausal women with idiopathic hyperprolactinemia or microprolactinomas (<1 cm) are treated with dopamine agonists if fertility is desired or galactorrhea is bothersome. Otherwise, estrogens and progestational agents may be prescribed to regularize menses and prevent osteoporosis. Several case reports of prolactinoma formation or enlargement after exposure to exogenous estrogens have been published. In our patient, a perimenopausal woman with presumably idiopathic long-standing hyperprolactinemia, a macroprolactinoma developed within 3 years after initiation of hormone replacement therapy for management of perimenopausal symptoms. The only clue for ordering a pituitary imaging study in this case was a substantial increase in the level of the serum prolactin. Treatment with cabergoline normalized the patient's serum prolactin level and considerably decreased the size of her pituitary adenoma. CONCLUSION: It is postulated that exogenous estrogens could have an important role in tumor development or growth in some patients with idiopathic hyperprolactinemia. Therefore, it is recommended that women with idiopathic hyperprolactinemia or microprolactinomas treated with estrogens be considered for concomitant therapy with dopamine agonists. In all cases, serum prolactin levels should be diligently monitored.

Estrogen Replacement Therapy↗

PubMed1999

Guidelines for the diagnosis and treatment of hyperprolactinemia.

Hyperprolactinemia is the most common endocrine disorder of the hypothalamic-pituitary axis. While it can occur in men, it occurs more commonly in women. The prevalence of hyperprolactinemia ranges from 0.4% in an unselected normal adult population to as high as 9-17% in women with reproductive disorders. There are many possible causes of hyperprolactinemia, falling into three general categories: physiologic, pharmacologic and pathologic. When specific treatable underlying causes have been eliminated and in cases of severe hyperprolactinemia, the most likely cause is a prolactin (PRL)-secreting pituitary adenoma. Microadenomas should be treated medically, with a dopamine agonist, if there is an indication for therapy (such as amenorrhea, infertility or bothersome galactorrhea). If there is no indication for therapy, microadenomas may be followed conservatively, as growth is uncommon. Macroadenomas may grow larger; medical therapy is recommended initially, with neurosurgical evaluation reserved for specific clinical situations, such as failure of medical therapy and evidence of mass effect despite medical therapy. In the United States, the dopamine agonists indicated for treatment of hyperprolactinemia are bromocriptine and cabergoline. Bromocriptine is usually given once or twice daily, while cabergoline has a long duration of action and is given once or twice weekly. Results of comparative studies indicate that cabergoline is clearly superior to bromocriptine in efficacy (PRL suppression, restoration of gonadal function) and tolerability.

Adult↗

PubMed1992

Gonadotropin-releasing hormone-associated peptide gene sequences in women with hyperprolactinemia.

OBJECTIVE: To determine if mutations in the structural gene for gonadotropin-releasing hormone (GnRH)-associated peptide are present in women with hyperprolactinemia. DESIGN: Patients with hyperprolactinemia and controls were studied retrospectively for GnRH-associated peptide gene mutations. SETTINGS: Patients seen in a clinical setting were studied at a medical school laboratory setting. PATIENTS: Fifteen women with hyperprolactinemia and two fertile controls with normal prolactin levels were studied. INTERVENTIONS: Genomic deoxyribonucleic acid (DNA) was extracted from each patient and subjected to Southern blot analysis and polymerase chain reaction (PCR). For Southern blot analysis, DNA was digested with EcoRI, XbaI, BglII, PstI, and BamHI and hybridized to two DNA probes for GnRH-associated peptide. Exons II to IV, which encode for the structural gene, were amplified by PCR. MAIN OUTCOME MEASURES: Fragment sizes from autoradiographs were compared among patients and controls. Amplified PCR products of exons II to IV of the GnRH-associated peptide were also compared. RESULTS: No large deletions, insertions, or polymorphisms were identified in women with hyperprolactinemia or controls by Southern blotting. Each of the exons was present and of normal size by PCR in the study patients and controls. CONCLUSIONS: No large deletions of the GnRH-associated peptide gene appear to be present in our patients with hyperprolactinemia. Small deletions, insertions, or point mutations are not excluded by this analysis.

Adolescent↗

PubMed2003

An evaluation of patients with hyperprolactinemia: have dynamic tests had their day?

Except for a few particular conditions, the diagnostic evaluation of hyperprolactinemia is easy since the routine use of magnetic resonance imaging (MRI) scan has permitted to identify even small microadenomas. Other conditions include the identification of large PRL molecular complex, dimers, trimers or polymers of PRL, called "big or big-big PRL", and of PRL autoantibodies and the biochemical finding of "high dose PRL hook effect". Finding elevated serum PRL levels should be considered as the beginning and not the conclusion of a diagnostic evaluation: first, a careful anamnesis should exclude possible physiologic, pharmacologic and organic causes of hyperprolactinemia; second, possibly one laboratory only, undergoing regularly quality controls, should analyze blood samples; serial serum PRL measurements at 0, 30, 60 min is a valuable and simple measure to identify stress-related hyperprolactinemia. In the past two decades several pharmacological tests were used in order to distinguish between small microprolactinomas and "non-tumoral hyperprolactinemia": the controversial results of these tests together with the availability of MRI has excluded all pharmacological tests in the work-up of hyperprolactinemia. MRI is preferred to computed tomography (CT) due to its better definition of very small lesions in the pituitary sella and better anatomical definition prior to surgery. Finally, once the diagnosis of prolactinoma is suspected, patients should be referred to a specialist centre for further assessment and treatment.

Decision Trees↗

PubMed2004

[Hyperprolactinemia and sexual activity of men--clinical aspect].

Hyperprolactinemia, particularly resulting from microprolactinoma, is known to induce erectile dysfunction. Contemporary published data do not allow to ascertain which prolactin (PRL) levels result in this type of sexual dysfunctions. The aim of this study was to evaluate the relationship between the extent of hyperprolactinemia and erectile dysfunction in 9 men with microprolactinoma and 8 patients with hyperprolactinemia as side-effects of sulpiride therapy. In all hyperprolactinemic males plasma PRL, LH, FSH and total testosterone levels were measured. The results showed that all patients with iatrogenic hyperprolactinemia were characterised by satisfactory sexual activity, although in 3 men hypotestosteronemia was revealed and in one patient gynecomastia was found. A range of PRL levels was 35-108 ng/ml. Among men with microprolactinoma the capability to lead a satisfactory sexual activity existed, even though in one patient PRL level was 2177 ng/ml, but in 3 other patients importance was observed when PRL concentrations were 281, 195 and 328 ng/ml. After bromocriptine therapy, when PRL levels diminished until 189, 78.3 and 110 ng/ml, the erectile dysfunction disappeared. Authors presume that sexual dysfunctions are not strictly connected with hyperprolactinemia and/or hypotestosterionemia, but probably are conditioned by other unexplicit factors (for example: a heterogeneous structure of PRL complexes).

Adult↗

PubMed2005

Clinical and etiological profile of hyperprolactinemia--data from a tertiary care centre.

OBJECTIVE: To study the clinical presentation and etiology of hyperprolactinemia, a common disorder encountered in endocrine practice. METHODS: We analyzed the clinical data, hormone profile and imaging reports of 187 females with documented hyperprolactinemia, over a period of 6 years (5 years retrospective analysis and one year prospective study). RESULTS: Majority of the 187 subjects studied presented in 3rd or 4th decade. Galactorrhoea was the commonest presenting symptom occurring in 159 subjects (85%), followed by amenorrhea in 68.9%; both amenorrhea and galactorrhea were seen in 45.4%. A microprolactinoma was demonstrated in 67 patients (35.8%), a nonfunctioning pituitary macroadenoma with stalk hyperprolactinemia occurred in 30 patients (16%) and polycystic ovarian disease was documented in 24 (12.8%). In 52 patients (27.8%) no apparent cause could be ascertained. CONCLUSIONS: Syndrome of amenorrhea and/or galactorrhea is the commonest presentation in hyperprolactinemia. Microprolactinoma was the most frequent identifiable etiology followed by idiopathic and stalk hyperprolactinemia in our series.

Academic Medical Centers↗

PubMed2006

Morphology of the epithelial cells and expression of androgen receptor in rat prostate dorsal lobe in experimental hyperprolactinemia.

The effect of hyperprolactinemia on the prostate has not been well investigated. Since androgens play an important role in prostate development, growth and function, the goal of the present study was to estimate the influence of hyperprolactinemia on expression of the androgen receptor (AR) in rat epithelial cells of prostate dorsal lobe and on morphology of these cells. Studies were performed on sexually mature male Wistar rats. The experimental group rats received metoclopramide (MCP) intraperitoneally to provoke hyperprolactinemia. The control group animals were given saline in the same way. For light and electron microscopy the prostate dorsal lobes were obtained routinely. To evaluate the intensity of immunohistochemical reaction for AR in epithelial cells, the optical density was measured and computer-assisted image analysis system was used. Morphological observations of the dorsal lobe epithelial cells were carried out in transmission electron microscope. MCP caused over twofold increase in prolactin (PRL) serum levels. In rats with hyperprolactinemia, the testosterone levels (T) were twofold decreased. The intensity of immunohistochemical reaction for AR in epithelial cells of dorsal lobe in the experimental group was significantly lower than in the control group. In the dorsal lobe epithelial cells of experimental group animals, the transmission electron microscopy (TEM) revealed highly dilated RER cisternae and reduced number of microvilli on the cellular surface when compared to the control group. The results show that hyperprolactinemia in male rats causes morphological abnormalities in the dorsal lobe of prostate. The abnormalities are caused by elevated prolactin either directly or indirectly through decreased level of testosterone. Decreased expression of AR in epithelial cells of prostate dorsal lobe is likely to be caused by decreased testosterone level.

Animals↗

PubMedDate not supplied

Hyperprolactinemia and 5-alpha-reductase activity.

A number of experimental data indicate that hyperprolactinemia inhibits the activity of 5-alpha-reductase; however, no information is available about the time required for this enzyme to re-activate after prolactinemia has returned to normal values. In the present study, five normal caucasian men, whose fertility had previously been proven, were given HCG (5000 IU/day by intramuscular route for three days) both in basal conditions and after sulpiride-induced hyperprolactinemia (dosage = 200 mg/day for ten days). In both conditions, the plasma levels of prolactin (PRL), testosterone (T), dihydro-testosterone (DHT), 17-beta-estradiol (E2), and dehydroepiandrosterone sulfate (DHAS) were monitored during the treatment with HCG and for an additional 24 hrs after HCG discontinuation. All hormones were assayed by RIA. Our results demonstrate that hyperprolactinemia causes a marked decrease (58%) of DHT, a less marked decrease (39%) of T, an increase (43%) of DHAS whereas only a small increase (2%) of E2 was observed. Steroids were shown to behave differently after the HCG tests performed in the two experimental conditions. In particular, the levels of DHT had a much more pronounced increased after HCG in the second test than in the first; in contrast, both DHAS and E2 had a less marked response after the second test. Our data, on the one hand, confirm that 5-alpha-reductase is inhibited by hyperprolactinemia; on the other hand, the hyperprolactinemia-induced block of this enzyme appears to be rapidly reversible because the enzyme is reactivated within 48-72 hrs after normalization of prolactin levels. (Normal values of prolactin were on the average achieved on the 4th day after sulpiride discontinuation).(ABSTRACT TRUNCATED AT 250 WORDS)

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

PubMed1986

[Hyperprolactinemia].

Hyperprolactinemia is frequent in clinical endocrinology. Its commonest causes are, besides pregnancy and lactation, drugs, mainly involving the generally used psychopharmaca and the equally ubiquitously prescribed estrogens. The single most important cause is a pituitary tumor, the prolactinoma, but lesions of the hypothalamus or pituitary stalk, primary hypothyroidism, liver cirrhosis and chronic renal failure, among others, may also provoke hyperprolactinemia. The clinical features of hyperprolactinemia in women are mainly amenorrhea, or irregular menses, galactorrhea, hirsutism, infertility and loss of libido. In men loss of libido and/or impotence are the most important symptoms, accompanied by infertility. Macroadenoma, more frequently seen in men than in women, may cause tumor symptoms such as headache and ophthalmologic disorders (visual field loss). The main biochemical finding is hyperprolactinemia, which should be repeatedly checked. In general, high concentrations are mainly found in large adenomas, while microadenomas usually involve only mild hyperprolactinemia, though there are numerous exceptions. While dynamic tests of prolactin secretion have provided useful information about the pathophysiology of prolactin secretion, their use in routine clinical work is controversial and of limited value. As a routine neuroradiological examination, high resolution CT of the pituitary area is to be recommended. In all hyperprolactinemic patients with suspicion of macroadenoma, ophthalmologic evaluation of fundus and visual fields should be performed. Dopaminergic drugs such as bromocriptine rapidly reduce serum prolactin levels in hyperprolactinemic women and men with micro- or macroadenoma. With these drugs considerable tumor shrinkage is possible.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗

PubMedDate not supplied

Luteal phase hyperprolactinemia.

OBJECTIVE: To determine the incidence of both isolated and repetitive prolactin elevations in the luteal phase of otherwise normoprolactinemic women. To see if sporadic luteal-phase hyperprolactinemia is associated with progesterone deficiency, and to explore a possible physiological basis for sporadic hyperprolactinemia by TRH challenge. SETTING: Hospital-based reproductive endocrinology/infertility service. DESIGN: Prospective measurement of luteal phase serum progesterone and prolactin in normoprolactinemic ovulatory women. TRH stimulation testing in volunteers with repetitive luteal phase hyperprolactinemia and normoprolactinemic controls. PATIENTS: 133 sequentially selected infertile, ovulatory women with normal prolactin levels in the proliferative phase of the cycle. INTERVENTIONS: Measurement of serum progesterone and prolactin during the luteal phase, based on the day of the LH surge. TRH testing in the midluteal phase of the cycle in patients with two or more luteal phase prolactin elevations, and in five normoprolactinemic volunteers in both the preovulatory and midluteal phase. RESULTS: Of 133 subjects, 85 (64%) had no prolactin level exceeding 20 ng/mL in the luteal phase. Thirty-three (25%) had two or more elevated levels, and were considered to have repetitive luteal phase hyperprolactinemia (LPH). TRH testing in control subjects resulted in a greater prolactin response in the preovulatory phase. The group with LPH demonstrated an initial elevation of prolactin greater than that of the normoprolactinemic controls, but a subsequent drop to levels lower than both preovulatory and midluteal normoprolactinemic controls by 45 minutes. CONCLUSIONS: Sporadic luteal-phase hyperprolactinemia is a relatively common event (36% of 133 subjects in the present series). Of these 48 women, 33 (69%) had repetitive elevations, suggesting the elevation in these subjects to be more than a random event. The physiological validity of this observation is further demonstrated by an abnormal response to TRH stimulation, but the normal levels of luteal phase progesterone leave questions as to its pathological importance.

Adult↗

PubMedDate not supplied

Alterations of testicular function induced by hyperprolactinemia in the rat.

The effects of hyperprolactinemia on testicular structure and pituitary-gonadal function were investigated in male rats. Hyperprolactinemia was induced in the Wistar-Furth rat by implantation of tissue fragments of a prolactin-secreting MtTW15 pituitary adenoma. The MtTW15 tissue was maintained in one animal group for 27 days (group A) and in another group for 37 days (group B). Appropriate age-matched controls were utilized in each study. Serum prolactin was significantly elevated (P less than 0.001) in both groups of MtTW15-bearing rats compared with their controls. The degree of hyperprolactinemia was more severe in rats of group B (2842 +/- 546 ng/ml) than in rats of group A (367 +/- 38 ng/ml). Accessory sex organ weights in group B rats were significantly lower than in controls, but were apparently unaffected in group A rats. Hyperprolactinemia induced definite but variable testicular alterations in both animal groups that presented as seminiferous epithelial disorganization, germ cell exfoliation, increased tubule wall thickness, and abnormal Leydig cell lipid content. Electron microscopy revealed structural disruption of Sertoli-germ cell junctional complexes and apical Sertoli cell cytoplasmic degeneration. The hyperprolactinemic rat exhibited significant reductions in serum luteinizing hormone (LH), testosterone (T), and androgen binding protein (ABP) when compared with controls. Eighty-six days following surgical removal of the MtTW15 tissue in a subgroup of group B rats, serum levels of prolactin and LH returned to normal, as did weights of accessory sex organs and testicular morphology. These results indicate that exposure to the MtTW15 adenoma and its later removal in the rat provides a workable model for studying the effects of hyperprolactinemia on testicular structure and function, and for identifying events involved in the subsequent recovery of spermatogenic disruption.

Adenoma↗

PubMed1989

Hyperprolactinemia decreases naloxone binding in the arcuate nucleus of ovariectomized rats.

Hyperprolactinemia suppresses endogenous prolactin (PRL) secretion and inhibits LH release in ovariectomized rats. Opiate peptides appear to mediate the suppressive effects of hyperprolactinemia on both endogenous PRL and LH secretion. A mechanism by which hyperprolactinemia may change the ability of opiates to influence PRL and LH is by altering the density of opiate receptors. We, therefore, examined the effect of hyperprolactinemia on the density of naloxone binding sites in hypothalamic regions that are important in the regulation of PRL and LH secretion. Female rats, ovariectomized for 4 days, were treated with ovine prolactin (oPRL) every 8 h for 2 days, and naloxone binding sites were measured using autoradiographic procedures. oPRL treatment suppressed the concentration of naloxone binding sites throughout the arcuate nucleus but had no effect in the median eminence, suprachiasmatic nucleus, and medial preoptic nucleus. There is evidence that the tuberoinfundibular dopaminergic neurons of the arcuate nucleus are directly influenced through opiate receptors. We propose that the observed decrease in the density of opiate receptors may occur on dopaminergic neurons. This theory provides an explanation for a mechanism for the suppression of endogenous PRL and LH by hyperprolactinemia: a decrease in opiate receptors will decrease opiate suppression of dopamine neurons allowing dopamine activity to increase. Increase in dopamine release are known to decrease PRL and LH secretion in ovariectomized rats. Alternatively, decreased naloxone binding may result from homologous down-regulation of receptors due to increased opiate activity. If opiate activity increases, it may directly inhibit LHRH neurons and may suppress the activity of inhibitory neurons leading to increased dopamine activity.

Animals↗

PubMed1982

Functional characterization of hypothalamic hyperprolactinemia.

PRL secretory dynamics were evaluated by several stimulation and suppression tests in nine patients with hyperprolactinemia due to organic hypothalamic disease. Basal PRL levels ranged between 20-63 ng/ml. There was a normal PRL response to TRH in eight cases (i.e. doubling of basal levels), whereas none of the seven tested subjects responded to sulpiride. The same dissociation of responses was not observed in any of the patients who were still hyperprolactinemic after surgery. Concomitant dopamine infusion resulted in sulpiride-induced PRL release in the four subjects so studied. None of 50 other hyperprolactinemic patients (11 with macroprolactinoma, 18 with microprolactinoma, and 21 with idiopathic hyperprolactinemia) showed PRL response to TRH but not to sulpiride. The TRH-induced PRL increase was significantly higher than that induced by sulpiride in hypothalamic hyperprolactinemia and significantly lower in idiopathic disease as well as in healthy controls; no differences were found in prolactinoma patients. The administration of substances resulting in stimulation of pituitary dopamine receptors, such as dopamine and L-dopa, induced a normal PRL suppression in 7 patients with hypothalamic disease so tested, whereas central nervous system-acting dopaminergic drugs, such as carbidopa plus L-dopa and nomifensine, failed to lower PRL levels in most cases (even when normoprolactinemic after surgery). These data suggest that the mild to moderate hyperprolactinemia found in many patients with hypothalamic lesions is due to dopamine deficiency at the pituitary level, that TRH and dopamine receptors at the lactotropes are intact in this condition, and that paired TRH and sulpiride tests may be of some diagnostic utility in hyperprolactinemic patients. They further suggest that subjects with so-called idiopathic hyperprolactinemia do not suffer from the type of hypothalamic derangement exhibited by patients with organic lesions of the hypothalamus.

Adult↗

PubMed1983

Normalization of androgen and sex hormone-binding globulin levels after treatment of hyperprolactinemia.

Twenty-eight women with amenorrhea, galactorrhea and hyperprolactinemia without hirsutism were studied before and after bromocriptine therapy for 2 months. Compared to 15 euprolactinemic controls, hyperprolactinemic women had elevated levels of dehydroepiandrosterone sulfate and androstenedione and lower levels of total testosterone (T), and androst-5-ene-3 beta, 17 beta-diol (Adiol), and 17 beta-estradiol (P less than 0.05). Unbound T and unbound Adiol were significantly elevated, while sex hormone-binding globulin binding capacity was decreased (P less than 0.05) and corticosteroid-binding globulin binding capacity was normal. After treatment with bromocriptine, dehydroepiandrosterone sulfate and androstenedione decreased to control levels, as did unbound Adiol, while 17 beta-estradiol and sex hormone-binding globulin binding capacity levels increased significantly (P less than 0.05). Five hyperprolactinemic women underwent ACTH stimulation tests before and after treatment, and the results were compared to those of seven controls. Steroid ratios in response to ACTH suggested normal 3 beta ol-dehydrogenase-isomerase, 17-20-desmolase and 17 beta-hydroxysteroid dehydrogenase enzymatic activities in hyperprolactinemia. Basal steroid ratios of T to 5 alpha-androstane-17 beta-01-3-one) (DHT) and of unbound T to unbound dihydrotestosterone were elevated (P less than 0.05), suggesting reduced 5 alpha-reductase activity in hyperprolactinemia which is normalized after treatment. Hirsutism was not present in these patients with hyperprolactinemia despite elevated levels of unbound T and Adiol, and may be explained by reduced 5 alpha-reductase activity. Our data suggest that the increased levels of androgens in these patients result from the hyperprolactinemia.

Adolescent↗