Biology of Reproduction, Vol 12, 212-222, Copyright © 1975 by Society for the Study of Reproduction

Time Relationships in Hormone Responses: Increased Ovarian Lactic Acid Production in vitro and Estrogen Production in vivo in Immature Female Rats Treated with PMS

¹ Department of Obstetrics and Gynecology and Physiology, Ralph L. Smith Research Center, University of Kansas Medical Center, Kansas City, Kansas 66103

The rate of lactic acid production by ovaries from intact and hypophysectomized immature female rats, incubated in vitro, increased quickly after intravenous injection of 20 IU of pregnant mare serum gonadotropin (PMS). This increased rate of glycolysis was maintained for at least 8 hours and then began to decrease; by 16 hours the rate was not different from that of starting controls. The rate could not be secondarily raised by another injection of gonadotropin but addition of dibutyryl cyclic adenosine monophosphate to the incubation medium produced the same high rate as did the initial exposure to gonadotropin. Anti-PMS antiserum completely abolished the effect of PMS when given simultaneously with the hormone, but a partial response was obtained when the antibody was given 30 minutes later. The effect of the PMS on glycolysis was totally lacking 3.5 hours after the injection of anti-PMS (4 hours after PMS). Serum estradiol concentrations did not increase significantly until 20 hours after PMS administration, but then continued to rise for the next 48 hours. Injection of anti-PMS at any time after giving PMS resulted in a complete loss of estrogenic response. The results emphasize the difference in the two responses to the gonadotropin; an increase in glycolysis occurs quickly after exposure to the hormone but has a short duration while secretion of estrogen is delayed for several hours but continues to increase several days. Both responses require the continued presence of hormone for maintenance.