[Pre-ovulatory peaks of gonadotropins. Recent data]

From recent data we know that: The duration of the LH peak seems to be more important than its amplitude for the induction of ovulation. Ovulation induction by hCG is not physiological; the absence of an FSH surge, and the long duration of LH activity would contribute to some of the luteal phase abnormalities. Recombinant hLH, on the other hand could give better results provided its action last about 48 hours. The results, however, are not as expected, probably because of the type of isoforms injected. The circulating FSH and LH isoforms found during the preovulatory peak of gonadotropins have a much higher in vitro biological activity than those found at other periods of the cycle. The production of FSH and LH recombinant of different biological activity is in process. The mechanism of the preovulatory peak of gonadotropins is still not fully understood. The respective role of GnRH and of the ovarian steroids has yet to be precisely determined in the human being. Ovarian peptides very probably also play a role.