THE ORIGIN OF SERUM PROGESTERONE DURING THE FOLLICULAR PHASE OF MENOTROPIN-STIMULATED CYCLES

The study was designed to investigate the source of progesterone secre tion during pituitary suppression and ovarian stimulation, It involved 416 women undergoing in-vitro fertilization (IVF) who were treated wi th gonadotrophin-releasing hormone agonist (GnRHa) and human menopausa l gonadotrophin (HMG) (group I), 139 women undergoing ovulation induct ion with HMG only (group II) and nine women who were diagnosed previou sly as late-onset adrenal hyperplasia and treated continuously with de xamethasone, in addition to ovulation induction (group In), During HMG treatment, serum oestradiol and progesterone were measured every 1-2 days, If progesterone concentration exceeded 3.0 nmol/l, at least 36 h before human chorionic gonadotrophin (HCG) administration, the patien ts were prospectively randomized to treatment with dexamethasone or no t and the hormones concentrations were measured again 12 h later, Mean age and pretreatment serum concentrations of dehydroepiandrosterone s ulphate, androstenedione, testosterone and luteinizing hormone/follicl e stimulating hormone (LH/FSH) ratio, were not significantly different in the patients with and without progesterone elevation, Pituitary do wn-regulation did not reduce the incidence of progesterone elevation ( 13.9 and 12.2% in groups I and II respectively), while in group LH, pr ogesterone concentrations did not increase. After dexamethasone admini stration a significant decrease in serum progesterone concentration wa s demonstrated (mean +/- SD, -2.1 +/- 1.4 and -1.6 +/- 1.2 in groups I and II respectively, while in the untreated patients it increased (+1 .9 +/- 1.9 and +4.2 +/- 4.8), The increase in serum progesterone conce ntrations was not accompanied by an increase in cortisol and 11-deoxyc ortisol but by an increase in LH. After dexamethasone administration t he concentrations of cortisol, 11-deoxycortisol and LH significantly d ecreased, Progesterone concentration was positively correlated with bo th oestradiol concentration (r = 0.290; P < 0.05) and the number of oo cytes retrieved (r = 0.207; P < 0.05), We conclude that at least a par t of serum follicular-phase progesterone appears to be of adrenal orig in, High oestrogen concentrations (or other ovarian factors) may cause changes in the hypothalamic-pituitary-adrenal axis and in adrenal enz yme activity as a part of the complex 'cross-talk' between the hypotha lamic-pituitary-ovarian and the hypothalamic-pituitary-adrenal axes.