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At least 505 records · Page 28Linked to original sources
PubMed1998

Compound heterozygous deletion of the PROP-1 gene in children with combined pituitary hormone deficiency.

Mutations in the prophet of Pit-1 gene (PROP1) have been shown to be responsible for combined pituitary hormone deficiency (CPHD) with deficiencies of growth hormone (GH), Prolactin (Prl), thyroid-stimulating hormone (TSH) and gonadotropins. We previously reported that homozygosity for a 2bp deletion in exon 2 (296delGA) accounted for CPHD in three patients from two Russian families. Here we report a second mutational hot spot in exon 2. This 2bp 149delGA deletion results in a frame shift that leads to the same serine to stop codon change at codon 109 (S109X). The predicted proteins are each truncated at residue 108 but diverge from the wild type sequence at different points in the homeodomain. Compound heterozygosity for the two mutations (149delGA/296delGA) was detected in 5 of 14 CPHD children from 4 families (36%). This provides the first evidence of heterozygosity for two common deletions as a cause of CPHD in Russian children.

Adolescent↗
PubMed1998

Standard and low-dose short adrenocorticotropin test compared with insulin-induced hypoglycemia for assessment of the hypothalamic-pituitary-adrenal axis in children with idiopathic multiple pituitary hormone deficiencies.

Insulin-induced hypoglycemia (IIH) is the gold standard test for assessment of the integrity of the hypothalamic-pituitary-adrenal (HPA) axis, but it may be hazardous. We sought to determine whether the standard (250 micrograms) or low-dose (1 microgram/1.73 m2) short ACTH test can replace IIH in patients with idiopathic multiple pituitary hormone deficiencies (MPHD). Three groups of subjects were studied: 1) control group, children with early or accelerated puberty and no other evidence of adrenal or pituitary pathology (n = 13, age 10.1 +/- 2.2 yr, 3 males); 2) patients with idiopathic hypothalamic pituitary insufficiency and either isolated GH deficiency or MPHD and preserved HPA function (n = 20, age 13.7 +/- 4.4 yr, 13 males); and 3) MPHD patients with impaired HPA axis function (n = 10, age 16.8 +/- 4.8 yr, 9 males). IIH and the 250 micrograms and 1 microgram/1.73 m2 ACTH tests were performed in groups 2 and 3; group 1 underwent only the ACTH tests. Pass peak cortisol level was defined as 520 nmol/L. No significant difference was noted between the standard and low-dose tests in the 30-min cortisol response to ACTH. Basal and peak cortisol levels attained on both ACTH tests were similar in groups 1 and 2 and significantly lower in group 3 (P < 0.0001). Both the 250 and 1 microgram ACTH tests were highly correlated with IIH (r = 0.71, P < 0.0001 for the 250 micrograms, r = 0.7, P < 0.0001 for the 1 microgram, n = 30), and both demonstrated high sensitivity (90% each) and specificity (100% and 90%, respectively) compared with IIH. We conclude that in idiopathic MPHD patients, both the standard and low-dose ACTH tests are equivalent to IIH in detecting HPA insufficiency. We suggest that they can replace IIH as a screening test for the integrity of the HPA axis in children with suspected MPHD.

Adolescent↗
PubMed1975

Effects of glucocorticoids on pituitary hormonal responses to hypoglycemia. Inhibition of prolactin release.

The characteristics of pituitary hormonal responses to insulin-induced hypoglycemia were investigated in 16 normal men. In all subjects, levels of blood sugar fell below 35 mg/100 ml. A statistically significant increase in mean plasma levels of prolactin, ACTH, cortisol and growth hormone was observed. Prolactin levels increased in all subjects but one; individual peak values were 1.4 minus 8.4 times greater than base levels. The kinetics of prolactin, GH and ACTH responses were similar; in particular, the onset of release (25 min) of prolactin, GH and ACTH was similar. After dexamethasone administration, insulin tolerance tests wererepeated in a number of subjects using adequate amounts of insulin to achieve hypoglycemia equivalent to that obtained in the control experiments. The administration of 1 mg of dexamethasone the evening before the test suppressed basal levels of ACTH and cortisol and the ACTH-but not the cortisol-response to hypoglycemia. Both basal levels of prolactin and prolactin response to hypoglycemia were significantly lowered but growth hormone response was not modified by administration of 1 mg of dexamethasone. The administration of larger doses of dexamethasone (1 mg every 6 h for 2 days) almost completely suppressed basal levels of ACTH, cortisol and prolactin, as well as the hypoglycemia-induced release of these hormones. In contrast, the growth hormone response to hypoglycemia was only partially inhibited. These findings demonstrate that both basal secretion and hypoglycemia-induced release of prolactin, ACTH, cortisol and growth hormone are suppressible by glucocorticoids.

Adolescent↗
PubMed2002

Current approaches for deciphering the molecular basis of combined anterior pituitary hormone deficiency in humans.

This review focuses on the general strategies currently used to decipher the molecular bases of combined pituitary hormone deficiency (CPHD) of genetic origin. By summarizing illustrative approaches that turned out to be successful for identifying an increasing number of genes involved in CPHD in the human, this article consider predictable obstacles specific to the investigation of these rare and heterogeneous conditions, while underlining the previously unsuspected roles of several of these genes during the development of extrapituitary structures.

Animals↗
PubMed1980

Lack of modulation of pituitary hormone stress response by neural pathways involving opiate receptors.

To evaluate the role of the opiate-like peptidergic pathways in modulating the pituitary hormone response to stress, we measured the GH, PRL, and cortisol responses to hypoglycemia and exercise in normal subjects with and without pretreatment with naloxone, given in the centrally active dose of 0.4 mg iv. Basal serum levels of GH, PRL, and cortisol were not changed significantly by prior naloxone administration. The maximum incremental response of GH to exercise was significantly blunted (13.1 +/- 1.6 vs. 6.0 +/- 1.4; P less than 0.001) by prior naloxone administration. Pretreatment with naloxone did not affect the responses of GH, PRL, or cortisol to hypoglycemia or the PRL response to L-dopa. On the basis of these studies we conclude that the opiate-like peptidergic pathways are not important in the regulation of basal levels of GH, PRL, and cortisol and have only a modest modulating influence on the stress-induced release of the hormones, which may be obscured in the face of severe stress.

Female↗
PubMed1984

Adaptation of anterior pituitary hormones to chronic noise stress in male rats.

We have studied the effects of acute and chronic noise on serum levels of pituitary hormones in male Wistar rats. Acute noise increased serum levels of corticosterone, prolactin, and luteinizing hormone and decreased serum GH. FSH was unaffected by this stressor. Chronic noise did not modify basal levels of any hormone studied, however responsiveness of some hormones to the same stimuli was altered. Reduced corticosterone, prolactin, and GH responses to noise was observed after previous chronic exposure to this stimuli. LH response followed the same pattern although it did not reach statistical significance. It might be concluded that adaptation to a repeated stress stimulus is not confined to the pituitary-adrenal axis, however, the degree of adaptation could vary between different hormones.

Animals↗
PubMed1983

Effects of 6-methoxy-1,2,3,4-tetrahydro-beta-carboline and yohimbine on hypothalamic monoamine status and pituitary hormone release in the rat.

Shortly after administration of 6-methoxy-1,2,3,4-tetrahydro-beta-carboline (6-MeOTHBC) and yohimbine to normal or hypothyroid rats [the latter exhibiting chronically elevated levels of serotonin (5-HT) neuronal activity in the hypothalamus] there was a highly significant increase in hypothalamic noradrenaline (NA) activity and in ACTH release concomittant with a reduction in hypothalamic 5-HT activity (P less than 0.01) and in growth hormone (GH) (P less than 0.01) and in thyroid stimulating hormone (TSH) (P less than 0.01) release from the pituitary. Both compounds caused an increase in hypothalamic dopamine (DA) metabolism and in pituitary prolactin (PRL) release in normal rats (P less than 0.01) but only yohimbine exerted this action in hypothyroid rats. Lower doses of 6-MeOTHBC exerted a relatively specific effect in hypothyroid rats, reducing (P less than 0.01) 5-HT neuronal activity in parallel with pituitary TSH secretion (P less than 0.05). While gross effects of 6-MeOTHBC and yohimbine were similar with respect to their effects on NA and 5-HT status in the hypothalamus, there were quantitative differences. 6-MeOTHBC always caused a greater decrease in 5-HT turnover and a lesser increase in NA turnover than did yohimbine. On the basis of these studies we suggest that the effect of tetrahydro-beta-carboline-related alkaloids on pituitary hormone release may be due to their influence on hypothalamic monoamine status and the subsequent alteration of the hypothalamic-pituitary control system.

Adrenocorticotropic Hormone↗
PubMed2007

Hormonal, pituitary magnetic resonance, LHX4 and HESX1 evaluation in patients with hypopituitarism and ectopic posterior pituitary lobe.

OBJECTIVE: LHX4 and HESX1 are important in early stages of pituitary development and their mutations can be associated with an ectopic posterior lobe (EPL) in the pituitary of patients with hypopituitarism. The EPL can be located at the median eminence or at the path of the pituitary stalk. The aim of this study was to analyse LHX4 and HESX1 and characterize the hormonal deficiency profiles, establishing relationships with magnetic resonance imaging (MRI) findings in these patients. PATIENTS AND DESIGN: Sixty-two patients with hypopituitarism associated with EPL were submitted to evaluation of pituitary function, analysis of MRI with EPL location and molecular analysis of LHX4 and HESX1 using polymerase chain reaction (PCR), digestion with restriction enzyme and automatic sequencing. RESULTS: Forty-two patients had a nonvisualized pituitary stalk (NPS), and 20 a visualized pituitary stalk (VPS). Most patients (95%) with NPS had combined pituitary hormone deficiency (CPHD), with ACTH deficiency in 85%. In patients with VPS, CPHD was found in 50% and ACTH deficiency occurred in only 20%. The frequency of the location of EPL was similar in patients with VPS and NPS: 35% at median eminence and 65% at the path of the stalk. No mutations in LHX4 and HESX1 were identified. Three new polymorphisms in LHX4 were found. CONCLUSIONS: ACTH deficiency is frequent in patients with hypopituitarism and NPS (85%), the location of EPL at the median eminence was not predictive of the hormonal profile [isolated GH deficiency (IGHD) or CPHD], and LHX4 and HESX1 genes mutations remain rare causes of hypopituitarism associated with EPL.

Adolescent↗
PubMedDate not supplied

Use of immunoperoxidase and immunogold methods in studying prolactin secretion and application of immunogold labelling for pituitary hormones and neuropeptides.

Two immunocytochemical methods, immunoperoxidase and immunogold (IG), were used in an attempt to study the dynamic process of prolactin release from stimulated rat pituitary mammotrophs. The immunogold method was also used to localize other pituitary hormones including growth hormone, follicle-stimulating hormone, luteinizing hormone, and the neuropeptides substance P, neuropeptide tyrosine, leu-enkephalin, and atrial natriuretic factor in peripheral nerves. Light-microscopic immunoperoxidase staining of prolactin revealed a unique distribution of immunoreactive mammotrophs. Two groups of cells were seen, one centrally located and one forming a narrow peripheral rim on the gland. The two groups were separated by a zone of nonimmunoreactive cells. In addition, the distribution of immunoperoxidase-stained material was not uniform in all mammotrophs. In some, prolactin immunoreactive material was clumped near the nucleus (in the Golgi cisternae); in others it was more diffused within the cytoplasm (but immediately surrounding the cisternae of rough endoplasmic reticulum). After stimulation of mammotrophs, via suckling, prolactin-immunoreactive material was visualized in extracellular spaces. With immunogold methods, prolactin labelling was seen mainly in secretory granules; but some labelling of Golgi cisternae and rough endoplasmic reticulum also occurred. Immunogold labelling revealed that material immunoreactive for leu-enkephalin and atrial natriuretic factor was present in nerve terminals in the rat paracervical ganglion. Material immunoreactive for substance P and neuropeptide tyrosine was present in nerve terminals in the guinea pig heart. Thus, in some situations the immunoperoxidase technique was useful and helped to visualize "grossly" the presence of specific antigens, but it was inadequate for fine ultrastructural localization of these antigens. The immunogold technique was excellent for precise localization of antigens and especially for the detection of colocalization of different antigens. This method can be used in very different structures, such as the adenohypophysis and peripheral nervous tissue, without any modification except for the nature of the antibodies.

Animals↗
PubMed1983

Effects of anterior pituitary hormones and their releasing hormones on physiological and behavioral functions in rats.

The effects of direct administration of TRH, TSH, LHRH, LH, ACTH, GH, FSH and prolactin into cerebral ventricle system on metabolic, respiratory, cardiovascular and behavioral responses were assessed in unanesthetized rats, Intraventricular administration of TRH, TSH, LHRH or LH caused hypothermia, decreased metabolism and/or cutaneous vasodilation at room temperature (22 degrees C). Intraventricular administration of FSH, ACTH or prolactin caused hyperthermia, increased metabolism and/or cutaneous vasoconstriction. Intraventricular administration of GH caused an insignificant change in thermoregulatory responses. There was no change in respiratory evaporative heat loss in response to either of the drugs tested. In addition, intraventricular administration of TRH, LHRH or LH caused tachycardia, hypertension and a reduction in the epinephrine-induced reflex bradycardia. In contrast, intraventricular administration of prolactin caused bradycardia, hypotension and an enhancement in the epinephrine-induced reflex bradycardia in conscious rats. There was no change in cardiovascular function in response to intraventricular administration of TSH, FSH, ACTH or GH. Furthermore, following intraventricular administration of TRH, but not TSH, LHRH, LH, FSH, GH, ACTH or prolactin three main categories of behavior were provoked: activity of normal type--forward locomotion stimulation, head and body rearing; stereotype activity--increased grooming and head swaying; and abnormal type behavior--tail elevation and piloerection in rats. The data indicate that most of the anterior pituitary hormones and their releasing hormones act through a central mechanism to influence physiological and/or behavioral functions.

Animals↗
PubMed1999

Effects of pituitary hormones on the prostate.

BACKGROUND: Although essential, androgens alone are not sufficient to induce normal growth and functionality of the prostate. Nonandrogenic hormones must also be involved in the proliferation of the prostate cancer cells which do not respond to antiandrogenic therapy and which thus become androgen-independent. Prolactin, but also growth hormone and luteinizing hormone, are potentially able to act on both normal and abnormal prostatic cells. METHODS: In this review we summarize data from the literature concerning the physiological and pathological implications of prolactin, growth hormone, and luteinizing hormone on the prostate. RESULTS: In rodent prostates, prolactin and growth hormone can induce a variety of effects independently of androgens (e.g., transactivation of certain genes, or synthesis of the major secretion products). Moreover, hyperprolactinemia is responsible for inflammation and dysplasia of the gland, while growth hormone promotes the development of prostate tumors in vivo in the mouse and rat. Growth hormone acts on the gland directly, through prostatic growth hormone receptors, and/or indirectly via the stimulation of insulin-like growth factor-I (IGF-I) synthesis in the liver. Luteinizing hormone receptor is expressed in rat and human prostates. Luteinizing hormone increases the amount of various transcripts in the rat prostate through an androgen-independent pathway. CONCLUSIONS: Prolactin, growth hormone, and luteinizing hormone, alone or synergistically with androgens, play physiologically significant roles in the normal prostate. The involvement of these hormones in the development of benign prostatic hyperplasia and prostatic carcinoma is an issue that needs to be addressed.

Animals↗
PubMed1993

Steroid and pituitary hormone responses to rowing: relative significance of exercise intensity and duration and performance level.

To analyse the relative significance of exercise intensity and duration as well as performance capacity, hormone changes were recorded in 16 male rowers in two experiments separated by a year. The test exercises consisted of 7-min (at the supramaximal intensity) and 40-min rowing (at the level of the anaerobic threshold) on a rowing apparatus. In addition, somatotropin and cortisol responses were estimated in rowing for 8 x 2000 m in 14 rowers of national class. All three tests caused significant increases in somatotropin and cortisol concentrations in the blood. Follitropin concentrations were elevated in the 7-min exercise test in the second experiment and in the 40-min exercise test in both experiments. Lutropin and progesterone concentrations increased during the more prolonged exercise in the first experiment. No common change was found in testosterone concentrations. Cortisol and somatotropin response to the 40-min rowing test at anaerobic threshold were more pronounced than to the 7-min exercise test at supramaximal intensity. When the rowers achieved a national class level of performance (the second experiment) the hormone responses to 7-min supramaximal exercise were increased. During the 8 x 2000-m rowing test cortisol but not somatotropin concentration increased to an extremely high level in the rowers of national class. It is concluded that in strenuous exercise cortisol and somatotropin responses were triggered by the exercise intensity threshold. The exact magnitude of the response would seem to have depended on additional stimuli caused by exercise duration and on possibility of mobilizing hormone reserves.

Adolescent↗