Effect of LH on ovarian steroidogenesis in the mid-pregnant rat.

In order to investigate the effect of LH on the steroidogenesis of ovary in mid-pregnant rats, the ovary from day 15 pregnant rats was sliced and incubated in Krebs-Ringer bicarbonate buffer containing various kinds of materials as follows; rat LH (NIAMDD-Rat LH-RP-1, 10, 100, 1,000 ng/ml); estradiol (0.1, 1.0, 10 micrograms/ml); testosterone (0.1, 1.0, 10 micrograms/ml); dihydrotestosterone (DHT, 0.1, 1.0, 10 micrograms/ml). One thousand ng/ml of LH significantly (p less than 0.01) increased progesterone release from the ovarian tissue. LH also stimulated testosterone release. One or 10 micrograms/ml of testosterone increased progesterone release (p less than 0.01), whereas DHT caused no increase in progesterone release. These results indicated that LH could stimulate progesterone release of the ovary on day 15 of pregnant rat, by affecting the production of testosterone or estradiol.