In Vitroandin VivoStimulation of Glycolysis in Prepubertal Rat Ovary by Luteinizing Hormone

Abstract

Luteinizing hormone has been shown to increase the rate of glucose uptake by isolated whole ovaries from prepubertal rats, whether administered to rats intravenously 4 hr before sacrifice or added directly to media in which the ovaries are incubated. The fraction of the utilized glucose which undergoes glycolysis to lactic acid under aerobic conditions is increased more by LH in vitro than by LH in vivo. Glucose oxidation is not significantly increased by either mode of hormone administration. Rates of glucose uptake and lactic acid production are substantially increased by anaerobic incubation. Under these conditions, LH in vivo is capable of exerting a still further stimulation of glycolysis, although LH in vitro is not. Under anaerobic conditions, more lactic acid is produced from endogenous materials, including glycogen, than under aerobic conditions. The stimulation of lactic acid production from glucose can be elicited by LH in vitro in concentrations as low as 0.2 μg /ml medium. Of the 3 other hormones (insulin, prolactin, FSH) tested for their abilities to stimulate ovarian glycolysis in vitro, FSH was the only one which produced a significant effect, although its activity was only approximately 4% that of LH.