Endocrine Abstracts

Introductions: Alterations of the somatotrophic and hypothalamic–pituitary–adrenal (HPA) axes occur frequently in patients with poorly controlled DM-1. These disorders could be related to abnormalities in the cholinergic tone regulating both hormonal axes.

Subjects and Methods: UFC (urinary free cortisol) on 24 h urine samples and the effects of placebo and pyridostigmine on ACTH, cortisol, GH and glucose circulating levels were studied in 16 young males: 10 normal controls and 6 patients with poorly controlled DM-1 (HbA1c 9.2%) without retinopathy or nephropathy. Placebo or pyridostigmine (120 mg) were given orally on different days at 0830. Blood samples were drawn at 0830, 0900 and then every 15 min until 1130. Area under the curve (AUC) was calculated for the full sampling period and for 1 hour intervals. Data are expressed as mean±SEM.

Results: UFC (47.21±7.29 vs 33.70±2.63 mcg/24 h, P<0.05), and GH and glucose levels were higher in diabetics than in controls, whereas ACTH and cortisol levels were not different. Pyridostigmine did not alter ACTH nor cortisol levels, while it raised GH secretion within each group, with the greatest increase in diabetics (AUC 0–60 min: 149.46±82.34 vs 23.68±12.01 ng/ml/60 min, P<0.05). UFC was negatively correlated with HbA1c. Basally, GH did not correlate with ACTH nor cortisol levels.

Conclusions: The higher UFC figures in diabetics suggest some degree of hypercortisolism in poorly controlled DM-1. Cholinergic activation in diabetics elicits GH hyperresponse, but does not modify cortisol nor ACTH levels, either in diabetics or controls. This fact speaks against an altered common mechanism in the cholinergic system regulating somatotrophic and HPA axes in DM-1, suggesting that cholinergic tone is not involved in the raised UFC excretion seen in these patients.