Preovulatory rise in progesterone.

Preovulatory rise in progesterone Dear Sir, We read with great interest the article by Eldar-Geva et al. (1998). In the late follicular phase of gonadotrophin-releasing hormone (GnRH) agonist/human menopausal gonadotrophin (HMG)-stimulated cycles they showed a concomitant increase of serum progesterone and luteinizing hormone (LH), both of which were reversible by the administration of dexamethasone. Based on these findings, they concluded that part of the follicular phase progesterone is of adrenal origin. Their results seem to support the notion that high oestrogen concentrations may cause discrete changes in the hypothalamic–pituitary adrenal axis and in adrenal enzymatic activity as part of a complex 'cross-talk' between the hypothalamic–pituitary– ovarian and the hypothalamic–pituitary–adrenal axes. This proposal is feasible, although there are still some other aspects which need to be given further consideration. Bognar et al. (1991) measured follicular fluid oestradiol, progesterone and testosterone concentrations in patients involved in an in-vitro fertilization (IVF) and embryo transfer programme. Of the three steroids, progesterone showed the best correlation with follicular maturation. A significant difference was established in progesterone content of first versus second class, as well as of first versus third maturity class follicles. The progesterone content of the mature follicles significantly exceeded that of the immature ones. Similarly, a significant difference was found in the progesterone/oestradiol ratios of the immature and mature follicles. The follicular progesterone probably originates from granulosa cells of growing follicles and can be regarded as the most likely source of the rise in serum progesterone concentration. In our earlier study (Bódis et al., 1993), we measured the progesterone, oestradiol, serotonin, noradrenaline and dopa-mine contents of follicular fluid samples obtained from 35 patients undergoing IVF and embryo transfer. Ovarian stimulation was performed using combined suppression–stimulation therapy. The GnRH agonist triptorelin (Decapeptyl; Ferring, Kiel, Germany) was used in a long protocol. Stimulation was carried out with individual dosages of HMG (Humegon; Organon, Obeschleissheim, Germany), varying from two to six 1 ml ampoules daily depending on the follicular maturation. Ovulation was induced by injection of 10 000 IU human chorionic gonadotrophin (HCG, Predalon; Organon), and aspiration of follicular fluid was performed 36 h later by ultrasound-guided vaginal puncture. Significantly higher pro-gesterone and noradrenaline concentrations have been found in human follicular fluid from cycles in which the oocyte cleaved and resulted in pregnancy, compared with follicular fluid containing uncleaved oocytes (Bódis et al., 1993). These results suggest that the higher concentration of progesterone and noradrenaline within …