The cytosolic enzyme phospho(enol)pyruvate carboxykinase (PEPCK) is markedly expressed in the intestinal mucosa of suckling rats. The expression is located in the small intestine, but there is no expression in stomach, colon, or cecum. The expression changes with age. The mRNA levels at birth are very low, increase after the first lactation, reach maximum levels between 3 and 9 days after birth, and then decrease smoothly. At weaning, when animals begin to feed on a solid chow diet, the expression falls to adult levels, which are hardly detectable. Mother's milk may influence the intestinal expression, since in rats weaned at Day 18, 3 days before normal weaning, the mRNA levels decreased dramatically. mRNA levels for PEPCK in liver present a rather different developmental pattern from that of intestine, remaining high at weaning and in adult rats. On the ninth day after birth, the mRNA levels are the same in intestine and liver.
Bibliographical noteFunding Information:
We gratefully acknowledge Dr. R. W. Hanson (Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH) for giving us the plasmid pPCK10. We also thank Mr. Robin Rycroft for his editorial help. This work was supported by Grant PB92-0544 from the ComisioÂn Interministerial de Ciencia y TecnologÂõa, Spain.
- mRNA levels
- suckling rats