Dexamethasone suppression of the calcitonin induced beta-endorphin, ACTH and cortisol secretion

Our previous observations have shown that calcitonin (CT) stimulates beta-endorphin, ACTH, and cortisol secretion. In order to give further information on the supposed hypothalamic pituitary involvement in this effect, we studied the influence of dexamethasone on this stimulative influence of CT. Six healthy women aged 50-65 years were investigated. All the subjects received 100 U CT salmon (Sandoz) i.v. at 0800 (0 time). Plasma beta-endorphin, ACTH, and cortisol were estimated every 30 min from -30 to 120 min by specific radioimmunoassays. The same subjects were evaluated a second time, at the same intervals, when 1 mg dexamethasone was administered per os at 11 PM the previous night and CT i.v. at 0800 the next morning. Beta-endorphin, ACTH, and cortisol levels (mean +/- SEM) rose significantly after 100 U CT from 5.6 +/- 0.17 to 16.75 +/- 1.8 pmol/L (p less than 0.001); from 39.6 +/- 6 to 88.0 +/- 3.1 pg/ml (p less than 0.0001) (from 8.7 +/- 1.3 to 19.4 +/- 0.7 pmol/L); and from 13.1 +/- 1.6 to 23.8 +/- 3.0 micrograms/dl (p less than 0.0001) [374 +/- 45 to 680 +/- 85 nmol/L], respectively. Dexamethasone suppressed almost completely the stimulatory effect of CT beta-endorphin rose from 4.9 +/- 0.12 to 6.3 +/- 1.3 pmol/L (n.s.), ACTH from 38.6 +/- 5.1 to 42.6 +/- 6.2 pg/ml (n.s.) (from 8.5 +/- 1.1 to 9.4 +/- 0.9 pmol/L) and cortisol from 0.88 +/- 0.23 to 0.88 +/- 0.18 microgram/dl (n.s.) (from 25.1 +/- 6.5 to 25.0 +/- 5.1 nmol/L).(ABSTRACT TRUNCATED AT 250 WORDS)