Effects of acetylsalicylic acid and indomethacin on growth hormone secretion in man.

To investigate the possibility that prostaglandins (PG) take part in the control of growth hormone (GH) secretion in humans, we have studied the effects of protracted and acute administration of acetylsalicylic acid (ASA) and indomethacin (ID), two PG synthesis inhibitors, on basal and insulin-stimulated GH secretion in normal volunteers. In eight subjects, oral administration of 3-2 g daily of ASA for 4 days clearly reached GH response to insulin hypoglycemia (p less than 0.01, ANOVA). In six additional subjects, GH response to hypoglycemia was not modified by a 4-day oral treatment with 300 mg daily of ID. The pattern of plasma free fatty acids (FFA) and blood glucose during the insulin tolerance test was not significantly affected by ASA treatment. After ID the O time value of the above parameters was somewhat higher than under basal conditions, while the drop of blood glucose, but not to FFA, was slightly more pronounced. Acute oral administration of 1.5 g ASA in 12 subjects did not appreciably modify baseline plasma GH, FFA, and blood glucose levels. By contrast, a single oral dose of 100 mg ID in 12 subjects caused a moderate but significant rise (p less than 0.05) of plasma GH levels together with a clear elevation (p less than 0.01) of plasma FFA and blood glucose levels with respect to a group of controls treated with a placebo. Collectively these results are compatible with the possibility that PG play a physiologic stimulating role in the control of GH secretion, although an effect of ASA and ID unrelated to PG inhibition cannot be ruled out, In any event, in view of the number of endocrine and metabolic alterations induced by ASA and ID, these drugs seem to merit further study.