Urinary gonadotrophins and luteinizing hormone-releasing hormone (LH-RH) like immunoreactivity during three normal reproductive cycles

Highly specific and sensitive radioimmunological methods were applied to determine the levels of LH-RH like immunoreactivity in urine previously extracted by spherosil and methanol, and to assay the gonadotropins, after extraction with acetone. The endogenous urinary LH-RH like immunoreactivity material was identified by chromatography on Sephadex G25, as having physico-chemical properties similar to those of the hormone found in unextracted urine after iv injection of synthetic LH-RH, but different from those of the synthetic decapeptide. The LH-RH like immunoreactivity and the gonadotropins were assayed in daily collected urine during the reproductive cycle of 3 normal women. A midcycle peak of both FSH and LH was found in each subject. No increases of LH-RH like immunoreactivity were found before or concomittant with the gonadotrophins surge. But peaks of urinary LH-RH like immunoreactivity were observed during the luteal phase, without subsequent increase of gonadotropin secretion.