SUPPRESSION OF LUTEINIZING HORMONE INDUCED BY ADRENOCORTICOTROPHIN IN HEALTHY WOMEN

Abstract

The effect of ACTH on serum concentrations of LH and FSH was studied in six healthy women in the follicular phase of the menstrual cycle, in six healthy men and in six patients (five men, one woman) with adrenocortical insufficiency. In healthy women the i.v. administration of synthetic 1–24 ACTH (0·25 mg) induced a fall in serum concentrations of LH from 11·1 ± 1·2 (s.d.) to 7·8 ± 0·6 i.u./l (P < 0·005) after 30 min and to 8·2 ± 0·7 i.u./l after 60 min. Upon continuous infusion of 1–24 ACTH (0·25 mg i.v., t = 480 min) LH fell to 6·7 ± 0·9 i.u./l (P < 0·005) in healthy women and to 6·1 ± 3·7 i.u./l (basal, 8·7 ± 3·9 i.u./l) in healthy men. In patients with adrenocortical insufficiency serum concentrations of LH were unchanged by 1–24 ACTH. Serum concentrations of FSH were not altered by 1–24 ACTH in any of the three groups. It is suggested that the effect of ACTH on LH secretion in healthy women is mediated by the acute rise of endogenous cortisol concentrations.