The effect of the oestrous cycle on the metabolism of isolated rat uterus

Abstract

Anaerobic glycolysis and O consumption of isolated rat uterus were highest dur-ing pro-oestrus and lowest at the end of oestrus. The changes in respiration were not so pronounced as those in anaerobic glycolysis. Aerobic glycolysis varied in the opposite sense and was lowest during pro-oestrus and highest immediately after oestrus. Pro-oestrus values were found in some rats at the end of dioestrus and at the beginning of oestrus (as judged from vaginal smears). When glucose was present in the Ringer''s soln. anaerobic glycolysis was constant, when no glucose was present it was lower and fell rapidly to a constant low value. Addition of glycogen or fructose to the Ringer''s soln. increased the rate only slightly and did not alter the type of curves obtained. Addition of KH2PO4, MgSO4 and extra KCl to the Ringer''s soln. did not alter the rate of anaerobic glycolysis. During anaerobic glycolysis, in the presence of glucose, glucose consumption was equal to lactic acid production, measured both manometrically and chemically. The Pasteur effect was operative throughout the cycle, i.e., anaerobic sugar usage was always greater than anerobic. Anaerobic sugar usage varied throughout the cycle, but aerobic sugar usage was approximately constant (both calculated from mano-metric results).