C-13 NMR KINETIC-STUDIES OF THE RAPID STIMULATION OF GLUCOSE-METABOLISM BY ESTROGEN IN IMMATURE RAT UTERUS

Glucose metabolism in control and estrogen stimulated rat uteri was in vestigated using C-13 NMR spectroscopy. By employing an NMR adapted pe rifusion system, and developing protocols and methods based on the app lication of [1-C-13]glucose labeling, it was possible to measure, with a temporal resolution of 10 min, the kinetics of glucose consumption, lactate production and C-13 incorporation into glutamate, alanine and glycogen. In control immature rat uteri, under aerobic conditions, th e rates (+/-SEM) of [1-C-13]glucose consumption and [3-C-13]lactate pr oduction were 24+/-2 and 7.5+/-0.5 mmol/g wet weight/h. The rates of s ynthesis of [4-C-13]glutamate, [3-C-13]alanine and C-13 labeling of gl ycogen at C-1 of its glucose moieties were significantly lower and wer e in the range 0.3-0.6 mmol/g wet weight/h. Thus, ca 35% of the labele d glucose was accounted for by the glycolytic and other observed pathw ays. In vitro stimulation of the uteri by estrogen was found to increa se significantly, within 1 h, glucose consumption by 80%, lactate prod uction by 150% and glutamate and glycogen synthesis by 150%, in parall el to a rapid hormonal induction of mRNA for the brain type isozyme of creatine kinase.