The Journal of clinical endocrinology and metabolism
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J. Clin. Endocrinol. Metab. · Dec 1990
Effects of repetitive administration of corticotropin-releasing hormone combined with lysine vasopressin on plasma adrenocorticotropin and cortisol levels in secondary adrenocortical insufficiency.
To examine the functioning of the hypothalamo-pituitary-adrenocortical axis in secondary adrenocortical insufficiency, we administered 100 micrograms synthetic human CRH, iv, plus 10 U lysine-8-vasopressin (LVP), im, three times daily for 3 consecutive days. The changes in plasma ACTH and cortisol levels during the administration and the response to an insulin tolerance test (ITT) conducted before and after the administration were determined. In three patients with isolated ACTH deficiency, basal plasma ACTH and cortisol levels were undetectablly low, and there was no response noted in the ITT or during CRH-LVP administration throughout the observation period. ⋯ Conversely, the ITT after repetitive CRH-LVP administration induced a higher cortisol response than the test before CRH-LVP administration in the post-Cushing's disease patients. No serious complications were noted in any of the patients during or after the treatment. The present findings indicate that 1) repetitive administration of CRH in combination with LVP is a safe and valuable provocation test to examine the pituitary ACTH reserve and the integrity of the pituitary-adrenocortical axis; 2) isolated ACTH deficiency is usually due to a defect at the pituitary level; 3) with respect to adrenocortical responsiveness, post-Cushing's disease patients show a better accumulation of the provocative effect than do post-Cushing's syndrome patients; and 4) both hypothalamic and pituitary dysfunction are responsible for adrenal hypofunction in patients after hypercortisolemia, but post-Cushing's syndrome patients (especially those with a short period of hypercortisolemia) appeared to have less impairment of hypothalamic ACTH-releasing activity than post-Cushing's disease patients.
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J. Clin. Endocrinol. Metab. · Dec 1990
Androgen response to endogenous insulin secretion during the frequently sampled intravenous glucose tolerance test in normal and hyperandrogenic women.
Women with ovarian hyperandrogenism frequently have insulin resistance, whose underlying mechanism remains to be determined. In the present study we have investigated the relationship between insulin sensitivity and the acute effect of endogenous insulin secretion on circulating androgen levels. Insulin sensitivity, glucose-mediated insulin release, and glucose/insulin-stimulated androgen responses were determined during a frequently sampled iv glucose tolerance test in a group of 19 women with clinical evidence of polycystic ovary syndrome (PCOS) and 9 age- and weight-matched controls. ⋯ Other androgen levels showed a modest nonsignificant decline during the study in PCOS and control groups. These findings confirm the weight-independent insulin resistance of some hyperandrogenic women. The failure of glucose-stimulated endogenous insulin secretion to significantly depress DHEA levels in insulin-resistant women with PCOS may account in part for their androgen excess.