LOW-DOSE OVINE CORTICOTROPIN-RELEASING HORMONE STIMULATION TEST IN DIABETES-MELLITUS WITH OR WITHOUT NEUROPATHY

The function of the hypothalamic-pituitary-adrenal (HPA) axis was eval uated in insulin dependent diabetics without (group I, n = 10) or with (group II, n = 10) established symptomatic neuropathy and in age- and weight-matched normal controls (n = 11). Since the corticotropin (ACT H)/cortisol response to the minimal effective dose of corticotropin-re leasing hormone ([CRH] 0.03 mu g/kg body weight) represents a useful t ool for HPA axis examination, all subjects were tested with the low-do se ovine CRH stimulation test. Experiments started at 8:30 AM, when CR H was injected after two basal blood samples were withdrawn, and laste d 2 hours. Basal serum levels of ACTH were similar in the three groups . Administration of CRH induced a small but significant increase in AC TH levels in all subjects; however, the CRH-induced ACTH increase was significantly higher in normal controls than in diabetic groups I and II. Furthermore, a significantly lower ACTH response was observed in g roup II than in group I. In contrast, basal and CRH-induced cortisol l evels were significantly higher in diabetics than in normal controls. Comparisons between diabetic groups showed that both basal and stimula ted cortisol secretion was significantly higher in group II than in gr oup I. When peak ACTH responses to CRH and basal cortisol levels were combined, a significant negative correlation was found (r = .545, P < .02). These data show that even uncomplicated diabetes mellitus is ass ociated with adrenal hyperfunction. Such an alteration is more pronoun ced in the presence of neuropathy. Copyright (c) 1995 by W.B. Saunders Company