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Apart from partial or complete insufficiency, further diseases of the pituitary with clinical impact are those associated with hormone overproduction such as acromegaly, Cushing's disease and prolactinoma. The cardinal symptom of pituitary insufficiency or disruption of the female cycle, loss of libido or sexual potency reflecting a lesion of the gonadotrophic axis. Hyperprolactinemia also results in a loss of gonadotrophic function. Macroadenomas of the pituitary gland often give rise to visual field defects, so that an ophthalmological work-up is a must. With the exception of hyperprolactinemia, measurement of basic hormone levels is not always sufficient to detect pituitary diseases. For the establishment of hormone deficiency, therefore, stimulation tests, and for detection of hypersecretion suppression tests, are carried out. Owing to the increasing utilization of cranial MRI, incidental detection of intrasellar tumors, the so-called incidentalomas, is becoming ever more common, and these lesions require at least an endocrinological investigation.
Two patients who developed Wernicke's Encephalopathy with subsequent hypothermia are described. Both patients responded rapidly to thiamine administration and one later had hypothalamic-pituitary function tests performed. This patient demonstrated depressed TSH response to TRH and a sluggish early cortisol response to adequate hypoglycaemia compared to 17 control subjects. These findings may suggest that previously described hypothalmic-pituitary abnormalties in chronic alcoholics may be mediated via thiamine deficiency and may also reflect hypothalamic damage contributing to the hypothermic state. The importance of intravenous thiamine administration in cases of coma of unknown aetiology is emphasised.
The progress about the control by the pituitary gland of TSH secretion involves the clinical use of TRH test. However some TSH deficiencies are due to an hypothalamic disorder. A better knowledge about the aminergic regulation of the TRH secretion is necessary to design a new test exploring the hypothalamic structures which control TSH secretion.
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OBJECTIVES: To determine whether hormonal dysfunction involving the hypothalamic-pituitary-adrenal (HPA) axis, prolactin (PRL) secretion, and sex hormone status contribute to development of systemic lupus erythematosus (SLE). METHODS: 11 patients with SLE and 9 healthy controls were tested for their total anterior pituitary gland reserve by simultaneous injection of corticotropin-, growth hormone- (GH), thyrotropin-, and gonadotropin-releasing hormone (GnRH). Serum concentrations of adrenocorticotropin (ACTH), cortisol, GH, thyroid stimulating hormone (TSH), PRL, luteinising hormone (LH), and follicle stimulating hormone (FSH) were measured at baseline and after injection. Baseline values of oestradiol, testosterone, and thyroxine were determined. RESULTS: Basal and stimulated serum concentrations of ACTH, cortisol, GH, and PRL were similar in both groups. In contrast, despite similar basal thyroxine levels the TSH response to TRH was significantly higher in patients than in controls. LH and FSH levels in premenopausal female patients of both groups were identical. In contrast, two of the three male patients were hypogonadal without compensatory increases of basal LH and FSH levels, but they retained excessive stimulatory capacity in response to GnRH. CONCLUSION: No significant alteration of the HPA axis was found in patients with SLE, which is inadequate in view of the continuing inflammation. GH and PRL secretion were normal. The pituitary-thyroid and pituitary-gonadal axes were affected in patients with newly diagnosed, untreated SLE.
Transfer of male golden (Syrian) hamsters from a 14L:10D (light:dark) to a 5L:19D photoperiod induced significant changes in pituitary function tested in vitro. Within 27 days after transfer to a 5L:19D photoperiod, basal prolactin (Prl) release was significantly depressed and response to dopamine (DA) was significantly enhanced as compared to Prl release by pituitaries from 14L: 10D hamsters. Follicle-stimulating hormone (FSH) release tended to be depressed after 9 or 27 days of 5L:19D exposure, but the effect was not significant. After 77 days of 5L:19D exposure, Prl release was further suppressed, while FSH release surpassed that seen in 14L:10D pituitaries. In vitro FSH response to luteinizing hormone releasing hormone (LHRH) was also enhanced at this time. After 15 weeks of exposure to a short photoperiod, FSH secretion was still elevated above control levels, but Prl release and Prl response to DA were no longer different from that of 14L: 10D controls. Secretion of luteinizing hormone (LH) in vitro, either basal or LHRH stimulated, was not affected by photoperiod at any time tested. From these results, we conclude that short photoperiod exposure does not reduce the pituitary's ability to secrete LH or FSH, although secretion of Prl is severely attenuated.
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To evaluate gonadotropin release in polycystic ovary syndrome (PCO), one or more of the following hypothalamic-pituitary function tests were performed on 24 patients with the syndrome. These tests included (a) the pulsatile pattern and day-to-day fluctuation of gonadotropin release; (b) effects of exogenous estrogen and antiestrogen (clomiphene) administration on gonadotropin release; and (c) pituitary responsiveness to maximal (150 mug) and submaximal (10 mug) luteinizing hormone-releasing factor (LRF) injections. In 10 of the 14 patients sampled frequently (15 min) for 6 h, luteinizing hormone (LH) levels were elevated above the concentration seen in normal cycling women (except the LH surge). These high LH concentrations appeared to be maintained by and temporally related to the presence of exaggerated pulsatile LH release, either in the form of enhanced amplitude or increased frequency. In all subjects, levels of follicle-stimulating hormone (FSH) were low or low normal, and a pulsatile pattern was not discernible. In four patients, daily sampling revealed marked day-to-day fluctuation of LH but not FSH. That the elevated LH levels were not related to a defect in the negative-feedback effect of estrogen was suggested by the appropriate fall of LH in four patients given an acute intravenous infusion of 17beta-estradiol. This infusion had no effect on FSH levels. In addition, clomiphene elicited rises of both LH and FSH that were comparable to the ones observed in normal women given the same treatment. The clomiphene study also suggested that the positive-feed-back mechanism of estrogen on LH release was intact when the preovulatory rises of 17beta-estradiol induced appropriate LH surges. The elevated LH levels appeared to be related to a heightened pituitary responsiveness to the LRF. This was found in the 11 and 2 patients given maximal (150 mug) and submaximal (10 mug) doses of LRF, respectively. The augmented pituitary sensitivity for LH release correlated with the basal levels of both estrone (P less than 0.025) and 17beta-estradiol (P less than 0.02). The net increase in FSH was significantly greater (P less than 0.001) in the PCO patients than the normal women with maximal doses of LRF. With the smaller dose study none of the injections had a discernible effect on FSH concentrations in either subject. The disparity between LH and FSH secretion could be explained by the preferential inhibitory action of estrogen on FSH release, coupled with a relative insensitivity of FSH release. These data indicate that in these PCO patients the abnormalities of the hypothalamic-pituitary regulation of gonadotropin secretion was not an inherent defect but represented a functional derangement consequent to inappropriate estrogen feedback, which led to a vicious cycle of chronic anovulation and inappropriate gonadotropin secretion.
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The typical patient with post-traumatic hypopituitarism is a young adult male presenting months to years after an automobile accident, following which he was unconscious for several days. He will probably have sustained a fracture of the base of the skull and on recovery is likely to have permanent visual or other neurological sequelae. Temporary or permanent diabetes insipidus may have occurred. The features of panhypopituitarism such as weight loss, fatigue, faintness, loss of libido, and impotence may have been ascribed to depression or the "postconcussion syndrome" and often inappropriate treatment and rehabilitation advised. The striking feature on review of the literature is that the pathological consequences of head injury to the pituitary and hypothalamus have been well described, while only 47 cases of traumatic hypopituitarism have been reported. The most likely reason for this disparity is that head injury of sufficient severity to cause hypothalamic and pituitary damage commonly led to death. More patients now survive, owing to the availability of intensive care; accordingly, most cases have been reported in the last 15 years. However, several patients are described in whom the initiating head injury was not associated with a skull fracture or followed by coma. We recommend that patients with major head injury (defined by post-traumatic amnesia greater than 24 hours), and in particular those with fractures of the base of the skull or diabetes insipidus should be closely monitored for symptoms and signs of endocrine dysfunction and appropriate dynamic pituitary-function tests performed.
A primary "empty" sella may be associated with significant hypothalamic-pituitary dysfunction. This report characterizes the endocrinologic and radiographic findings in six patients with hyperprolactinemia (range 34.3 to 1,170 ng/ml) ultimately found to have an enlarged empty sella. Lateral skull x-ray films and thin-section tomograms were suggestive of pituitary tumors in all patients. Four patients underwent transphenoidal sellar exploration after pneumoencephalography (PEG) failed to demonstrate air within the sella. The inability of PEG to demonstrate an empty sella in two patients was explainable on the basis of an intact diaphragma sellae with previous transient intrasellar pathology responsible for the sellar enlargement. Dynamic hypothalamic-pituitary testing yielded no consistent pattern of response. These studies suggest that an empty sella: (1) may be associated with hyperprolactinemia, regardless of etiology, (2) is not diagnosable by dynamic hormonal testing, and (3) may be indistinguishable from a pituitary tumor by current radiographic techniques.
Sleeping sickness (SS; African trypanosomiasis) is an anthropozoonosis transmitted by the tsetse fly. Infection with Trypanosoma brucei in humans is associated with adynamia, lethargy, anorexia, and more specifically amenorrhea/infertility in women and loss of libido/impotence in men. Recent evidence suggests that experimental infection in animals with Trypanosoma brucei species causes polyglandular endocrine failure by local inflammation of the pituitary, thyroid, adrenal, and gonadal glands. In a cross-sectional study we investigated the prevalence and significance of neuroendocrine abnormalities in 137 Ugandan patients with SS. In the untreated stage of the disease, there was a high prevalence of adrenal insufficiency (27%), hypothyroidism (50%) and hypogonadism (85%). Pituitary function tests suggested an unusual combined central (hypothalamic/pituitary) and peripheral defect in hormone secretion. Specific therapy resulted in a rapid recovery of adrenal/thyroid function, whereas hypogonadism persisted for years in a substantial portion of patients. We did not detect pituitary, thyroid, adrenal, and gonadal autoantibodies in patients with endocrine dysfunction, ruling out an autoimmune origin of the endocrine abnormalities. However, the presence of hypopituitarism correlated with high cytokine concentrations (TNF-alpha, IL-6) which--together with direct parasitic infiltration of the endocrine glands--are involved in the pathogenesis of SS-associated endocrine dysfunction.
A 41-year-old man was referred to Kyushu University Hospital for evaluation of hypothyroidism and hypocortisolemia. Pituitary function test revealed the deficiency of GH(growth hormone), ACTH(adrenocorticotropic hormone), prolactin and TSH(thyroid stimulating hormone). MRI showed empty sella and agenesis of corpus callosum. Clinical diagnosis was hypopituitarism with midline brain anomaly. Septo-optic-pituitary dysplasia (SOPD) is a syndrome characterized by agenesis of septum pellucidum or corpus callosum, optic nerve hypoplasia and congenital hypothalamic-pituitary insufficiency. Our case had no ocular anomalies, but today it is regarded as a variant form of SOPD. Evaluation of the integrity of midline brain structures in patients with congenital hypopituitarism is thus thought to be important for their etiology.
The efficiency of L-dopa and exercise tests have been compared to diagnose the lack of human growth hormone. Both tests gave similar results. The exercise test is recommended as a screening method in large populations to discard growth inhibition due to HGH deficiency, because of its easy, quick and painless application to patients.