The effects of pregnancy, lactation and involution on the metabolism of glucose by rat parametrial adipose tissue

Abstract

The incorporation of¹⁴C from [1-¹⁴C] and [6-¹⁴C]glucose into CO₂, fatty acids and glycerol by rat parametrial adipose tissue was measured at intervals during pregnancy, lactation and involution. There were small increases in the incorporation of both the C-1 and C-6 atoms into CO₂and glycerol on the seventh and sixteenth days of pregnancy. Fatty acid synthesis from glucose was negligible on the twentieth day of pregnancy and during lactation. Three days after weaning the rate of oxidation of the C-1 atom was doubled and the incorporation of both carbon atoms into fatty acids was increased at least 20-fold. There were no changes in the activities of glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase during pregnancy and lactation, but 3 days after weaning the activities of both enzymes were doubled. These results are discussed in relation to other evidence that the total body fat is increased during pregnancy, and to the idea that the fat depots are mobilized during lactation.