Ketogenic mitochondrial 3-hydroxy 3-methylglutaryl-CoA synthase gene expression in intestine and liver of suckling rats.

The ketogenic mitochondrial 3-hydroxy 3-methylglutaryl-coenzyme A (HMG-CoA) synthase gene is expressed in intestine of suckling rats, its mRNA levels changing with age. Intestine mitochondrial mRNA values reach maximum levels on the 12th postnatal day and then decrease smoothly. Mother's milk may influence the intestine expression, since mRNA levels at birth are very low, increasing after the first lactation. Moreover, rats weaned at either Day 18 or 21 decrease their mRNA levels dramatically and there is no expression in adult rats. Mitochondrial HMG-CoA synthase is also expressed in liver of suckling rats but the developmental pattern of mRNAs is different from that in intestine, showing the highest values at Day 3 of life. mRNA levels in liver are lower than in intestine for most of the suckling period, suggesting the physiological relevance of the intestine for the ketogenic process of the whole body. Liver mRNA levels on weaning and in adult rats are high enough to sustain hepatic ketogenesis.