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At least 163 records · Page 9Linked to original sources

Diagnostic testing for pituitary pars intermedia dysfunction in horses.

Pituitary pars intermedia dysfunction is a slowly progressive disorder that afflicts most breeds of horses. Because it shares features with human Cushing disease, it has been referred to as equine Cushing disease. A variety of tests of pituitary-adrenocortical function were performed on horses with evidence of pituitary pars intermediate dysfunction, and results were compared with those in healthy control horses. Diurnal variations in plasma cortisol concentration were not statistically different between control horses and those with pituitary pars intermedia dysfunction. An ACTH stimulation (1 U of natural ACTH gel/kg of body weight, IM) test or a combined dexamethasone suppression test (10 mg, IM) and ACTH stimulation (100 mg of synthetic ACTH, IV) test also failed to distinguish horses with pituitary pars intermedia dysfunction from control horses. A significant (P < 0.001) dose-related suppression of cortisol concentration in response to increasing doses (5, 10, 20, and 40 micrograms/kg) of dexamethasone was observed in control horses but not in those with pituitary pars intermedia dysfunction. On the basis of plasma cortisol concentration, the dexamethasone suppression test, using 40 micrograms/kg, whether initiated at 5 PM with sample collection at 15 (8 AM) and 19 (12 PM) hours after dexamethasone administration, or initiated at 12 AM with sample collection at 8 (8 AM), 12 (12 PM), 16 (4 PM), 20 (8 PM), and 24 (12 AM) hours after dexamethasone administration, reliably distinguished between control horses and those with pituitary pars intermedia dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗

Prevalence of pituitary deficiency in patients after aneurysmal subarachnoid hemorrhage.

After aneurysmal subarachnoid hemorrhage (SAH), patients frequently present with persistent bodily, psychosocial, and cognitive impairments that resemble those of patients with untreated partial or complete pituitary insufficiency. Because of these similarities, the authors hypothesized that aneurysmal SAH may cause pituitary dysfunction. Pituitary function testing was performed in 40 aneurysmal SAH patients between 12 and 72 months after the SAH. A combined TRH-LHRH-arginine test and the insulin tolerance test were performed on two separate days. Only 18 of 40 (45%) of the tested patients had normal pituitary function. Five of 40 exhibited isolated severe GH deficiency (GHD), and an additional three of 40 had severe GHD plus corticotroph deficiency. Isolated corticotroph deficiency was seen in 13 of 40 patients, and one patient showed isolated thyrotroph deficiency. All but one patient with corticotroph insufficiency were female. Patients with severe GHD had gained significantly more weight since their SAH than patients without GHD and exhibited a significantly higher body mass index. None of the clinical parameters indicative of a poor neurological outcome in aneurysmal SAH were related to pituitary insufficiency. In summary, neuroendocrine dysfunction was identified in a substantial portion of patients with previous aneurysmal SAH and should be borne in mind as a potential long-term sequel of the illness.

Adrenal Glands↗

The primary empty sella syndrome: analysis of the clinical characteristics, radiographic features, pituitary function and cerebrospinal fluid adenohypophysial hormone concentrations.

Twelve cases of the primary empty sella syndrome were analyzed in regard to clinical findings, roentgenographic features, pituitary function and cerebrospinal fluid adenohypophysial hormone concentration. The findings were compared with those in 247 cases of the primary empty sella syndrome reviewed from the literature in order to determine the major characteristics of this disorder. The majority of patients are obese, multiparous women with normal pituitary reserve, normal visual fields and undetectable adenohypophysiol hormone concentrations in cerebrospinal fluid. In addition occasional patients witll have hypertension, pseudotumor cerebri and cerebrospinal fluid rhinorrhea. Patients who present with the typical features of the primary empty sella syndrome should be evaluated periodically with pituitary function testing, visual field examinations and cerebrospinal fluid adenohypophysial hormone determinations. If these parameters remain normal during careful follow-up studies, the patient is likely to have an empty sella, and pneumoencephalographic and angiographic studies can be avoided.

Adult↗

Hypothalamic-pituitary dysfunction in respiratory hypoxia.

Eight hypoxic male patients with stable chronic obstructive airways disease were submitted for combined anterior pituitary function testing. All subjects showed normal growth hormone and essentially normal cortisol responses to adequate hypoglycaemia, two subjects showed delayed responses of thyroid stimulating hormone to administered thyrotrophin releasing hormone and all had basal prolactin levels within normal limits. Basal levels of luteinising hormone were significantly lower than in the group of age-matched controls (p less than 0.02) but there was a normal increment after the injection of gonadotrophin releasing hormone. Basal levels of follicle stimulating hormone were significantly lower than in the controls (p less than 0.01), and there was also a reduced response from the pituitary after injection of gonadotrophin releasing hormone (p less than 0.01). Resting levels of the thyroid hormones thyroxine and tri-iodothyronine were normal while the expected subnormal testosterone level was observed (p less than 0.05). These results show that hypoxia can produce abnormalities of hypothalamic-pituitary function and that these are primarily located in the hypothalamic-pituitary-testicular axis.

Adult↗

A combined test of anterior pituitary reserve.

Determination of the functional reserve of the anterior pituitary gland requires the serial measurement of hormones released from the pituitary by specific stimuli. Individually, insulin-induced hypoglycaemia, thyrotrophin releasing hormone (TRH) and gonadotrophin releasing hormone (GnRH) have proved to be reliable stimuli for the release of the various pituary hormones. The maximum incremental hormone response of growth hormone, cortisol, luteinising hormone, follicle stimulating hormone, thyrotrophin, triiodothyronine and prolactin has been assessed after the simultaneous administration of insulin, TRH and GnRH in six normal subjects. These responses have been compared to previously determined responses in a normal population when insulin, TRH or GnRH have been given separately. There were no significant differences in the peak response or the maximum incremental response of any hormone. The test has been used to assess the pituitary reserve of 54 patients with disorders of the hypothalamic-pituitary axis, and five patients have been assessed both before and after hypophysectomy. The test is found to be convenient, sensitive and reliable in the assessment of pituitary reserve.

Acromegaly↗

[Test with ovine corticotropin-releasing hormone (oCRH): clinical application and reference values in the young adult and the postmenopausal women].

CRH (corticotropin-releasing hormone) is a hypothalamic polypeptide that stimulates ACTH secretion by the anterior pituitary and, subsequently, cortisol secretion by the adrenal cortex. CRH test administration is indicated in the differential diagnosis of Cushing syndrome and in the assessment of corticotropic function in different pituitary conditions. Both human CRH (hCRH) and ovine CRH (oCRH) can be used by i.v. injection. Intrinsic ACTH-releasing activities of the two molecular forms are similar. Nevertheless, and contrary to hCRH, oCRH does not interact with the human CRH specific binding protein (CRH-BP) and the use of this ovine form could be useful in testing pituitary function while avoiding possible changes in peptide activity due to protein binding. The present study was conducted in 3 distinct groups of human volunteers to evaluated the ACTH and cortisol responses to i.v. oCRH (1 micrograms per kg body weight) at noon (oCRH test). 24 healthy, nonobese subjects, not under medication, participated in the study. The first group consisted of 8 young men, the second of 8 women of childbearing age and the third of 8 menopausal women. Tolerance to the oCRH test was excellent in all 3 groups. A significant increase in plasma ACTH and cortisol was observed in all the subjects, with peak occurrence for ACTH between 15 and 60 minutes after oCRH and between 20 and 120 minutes for cortisol. The responses were not sex-related among the young subjects, but the menopausal women displayed a higher cortisol increase than the other 2 groups.

Adrenocorticotropic Hormone↗

Hypopituitarism following traumatic brain injury and aneurysmal subarachnoid hemorrhage: a preliminary report.

OBJECT: Recognition of pituitary hormonal insufficiencies after head injury and aneurysmal subarachnoid hemorrhage (SAH) may be important, especially given that hypopituitarism-related neurobehavioral problems are typically alleviated by hormone replacement. In this prospective study the authors sought to determine the rate and risk factors of pituitary dysfunction after head injury and SAH in patients at least 3 months after insult. METHODS: Patients underwent dynamic anterior and posterior pituitary function testing. Results of the tests were compared with those of 18 age-, sex-, and body mass index-matched healthy volunteers. The 22 head-injured patients included 18 men and four women (mean age 28+/-10 years at the time of injury) with initial Glasgow Coma Scale (GCS) scores of 3 to 15. Eight patients (36.4%) had a subnormal response in at least one hormonal axis. Four were growth hormone (GH) deficient. Five patients (four men, all with normal testosterone levels, and one woman with a low estradiol level) exhibited an inadequate gonadotroph response. One patient had both GH and thyrotroph deficiency and another had both GH deficiency and borderline cortisol deficiency. At the time of injury, all eight patients with pituitary dysfunction had an initial GCS score of 10 or less and, compared with the 14 patients without dysfunction, were more likely to have had diffuse swelling, seen on initial computerized tomography scans (p < 0.05), and to have sustained a hypotensive or hypoxic insult (p = 0.07). Of two patients with SAH who were studied (Hunt and Hess Grade IV) both had GH deficiency. CONCLUSIONS: From this preliminary study, some degree of hypopituitarism appears to occur in approximately 40% of patients with moderate or severe head injury, with GH and gonadotroph deficiencies being most common. A high degree of injury severity and secondary cerebral insults are likely risk factors for hypopituitarism. Pituitary dysfunction also occurs in patients with poor-grade aneurysms. Postacute pituitary function testing may be warranted in most patients with moderate or severe head injury, particularly those with diffuse brain swelling and those sustaining hypotensive or hypoxic insults. The neurobehavioral effects of GH replacement in patients suffering from head injury or SAH warrant further study.

Adolescent↗

Endocrinological aspects of Langerhans cell histiocytosis complicated with diabetes insipidus.

Langerhans cell histiocytosis (LCH) is a rare disorder and may be complicated with hypopituitarism and diabetes insipidus (DI) due to invasion of the hypothalamic-pituitary area. In this study, 10 patients with complete (4) and partial (6) type central DI were found among 125 LCH patients in our hospital records. The water deprivation test, followed by the pitressin test, was performed to confirm DI. Hypothalamic-pituitary endocrine function tests were carried out on these 10 patients at the initial diagnosis and during follow-up. All patients revealed growth hormone insufficiency in the insulin hypoglycemic tolerance test. Four patients had impairment of cortisol secretion, demonstrated by insulin hypoglycemic stimulating test results. Two patients had poor response in the thyrotropin releasing hormone stimulating test. Two patients had only partial responses in the luteinizing hormone releasing hormone test. Four patients had hyperprolactinemia. All patients underwent surgical treatment followed by chemotherapy and/or radiotherapy. One patient completely recovered from the endocrine disorder, 3 patients required smaller doses of desmopressin, and one patient had normal adrenal, thyroid, and gonadal function. Hypothalamic-pituitary disorders in LCH should not be neglected. Treatment of LCH can partially or completely reverse associated endocrine disorders. Therefore, endocrine studies and hormone replacement should be mandatory for patients with LCH.

Adolescent↗

Metabolic and clinical studies on patients with acromegaly treated with bromocriptine over 22 months.

In twenty-two patients with active acromegaly who were untreated or unsuccessfully operated or irradiated (mean growth hormone (GH) values greater than 4 ng/ml) the following investigations were performed: routine laboratory tests, tomography of pituitary fossa, oral glucose tolerance tests, TRH and other pituitary function tests and GH profiles over 5-10 h before and during bromocriptine treatment with daily doses between 7.5 and 50 mg. In seventeen patients GH was suppressed to less than 50% by bromocriptine, in thirteen of them it was normalized on at least one occasion. A TRH induced GH release was observed in all but two responders to bromocriptine before therapy. This effect of TRH was not blunted during treatment with bromocriptine and also in the two patients with negative tests before therapy a significant GH increase was observed. In no non-responder to bromocriptine was a significant increase of GH after TRH observed. One patient showed a secondary resistance to bromocriptine during a period of treatment with griseofulvin. In the remaining sixteen patients the GH suppression has been consistent for between 3 and 22 months. A single dose of pimozide abolished the bromocriptine effect on GH totally in one patient; in others a slight or no significant effect was observed. Tissue swelling and sweating decreased in all bromocriptine responders and glucose tolerance improved in five patients. In four diabetic patients a partial or full remission of diabetes occurred. Apart from postural hypotension after the first administration in two patients no other severe side effects have been observed. Sella size and the other pituitary functions did not change during the time of the study. It seems that a high percentage of acromegalics may be successfully treated with bromocriptine.

Acromegaly↗

Influence of 6-week, 6 days per week, training on pituitary function in recreational athletes.

The influence on pituitary function of 6 weeks of training on 6 days a week was examined in six recreational athletes. Endurance training on a bicycle ergometer for 31-33 min was performed on 4 days each week at 90-96% (weeks 1-3) and 89-92% (weeks 4-6) of the 4 mmol lactate thresholds determined on day 0 and day 21, respectively, with interval training of 3-5 x 3-5 min in addition on 2 days a week at 117-127% and 115-110%, respectively. Determination of the serum hormone levels and a combined pituitary function test (200 micrograms thyrotropin releasing hormone (TRH), 100 micrograms gonadotrophin-releasing hormone (GnRH), 100 micrograms corticotrophin releasing hormone (CRH), 50 micrograms growth hormone releasing hormone (GHRH)) were made before training, after 6 weeks of training and after another 3 weeks of recovery. Training increased performance at 2 mmol lactate by 25%, at 4 mmol by 12%, and maximum performance by approximately 12%. The releasing hormone-stimulable prolactin, thyroid stimulating hormone (TSH) and somatotrophic hormone (STH) synthesis-secretion capacity remained unchanged, the adrenocorticotrophic hormone (ACTH) was increased after training. Cortisol release was reduced, follicle-stimulating hormone (FSH)-synthesis-secretion capacity was increased after training, and the luteinizing hormone (LH)-synthesis-secretion capacity reduced. This had no influence on base or exercise-induced serum hormone levels (cortisol, aldosterone, insulin, prolactin, FSH, LH, TSH, ACTH, ADH and STH), which showed no dependence on training, except for free testosterone which showed a decreasing trend (P < 0.10) of 19-25% and post-exercise ACTH which showed an increasing trend of 33% (P < 0.10). Conditioning (cortisol sensitivity and ACTH response) or adaptation (FSH and LH responses) to changed testosterone serum levels and altered spermatogenesis is discussed.

Adrenocorticotropic Hormone↗