Correlation of the bioactivity of luteinizing hormone in follicular fluid with oocyte maturity in the spontaneous cycle.

This study was done to measure the bioactivity of luteinizing hormone (LH) in follicular fluid (FF) and to correlate this and other hormonal values with oocyte maturity in the spontaneous cycle. Twenty follicles (greater than 18 mm) from 18 ovulatory patients were obtained, and FF, according to oocyte maturity, was divided into three groups (I to III) of increasing maturity. FF progesterone correlated with maturity and was highest (P less than 0.01) in group III; estradiol, prolactin, and follicle-stimulating hormone were similar in the three groups. Immunoreactive LH was similar in groups I and II but was highest (30.5 +/- 7 mIU/ml) in group III (P less than 0.02). Bioactive (bio) LH was much higher in group III follicles (1307 +/- 387 mIU/ml); the bio:immunoreactive LH ratio also increased significantly (P less than 0.05). FF progesterone correlated positively with bio LH (r = 0.89, P less than 0.005) and the bio:immunoreactive LH ratio (r = 0.9, P less than 0.001); immunoreactive LH did not correlate. These data suggest that bioactivity of LH is an important correlate of oocyte maturity and that local ovarian factors may modulate these concentrations in FF.