Enzyme Changes in the Offspring of Female Rats due to Long-Term Administration of Cyclic AMP and Insulin before Pregnancy.

We studied the effects of insulin and cAMP on the offspring of female rats after daily treatment with these substances over 4 weeks. In adult offspring from cAMP-treated females, activities of pyruvate kinase and glucose-6-phosphate dehydrogenase decreased in the liver and brain and activities of NADP-dependent malate dehydrogenase and 6-phosphogluconate dehydrogenase decreased in the liver. In the offspring of insulin-treated females, we observed only activation of glucose-6-phosphate dehydrogenase and malate dehydrogenase in the liver and only in females. Enzyme activity probably correlates with their content, as no changes in their kinetic properties were observed under these conditions. Long-term hormone treatment before pregnancy can affect the expression of genes for some enzymes in the offspring due to transmission of epigenetic signals by the ovum. However, further studies are required to confirm this mechanism.