Regulation of de novo phosphatidylcholine biosynthesis during renal growth.

Potential regulatory steps of de novo renal cortical synthesis of phosphatidylcholine (PC) were investigated during renal growth in rats. Twenty-four hours following unilateral nephrectomy, cortical PC content was increased in the remaining kidney when compared with sham-operated controls, 3.47 +/- 0.07 and 2.79 +/- 0.14 mumol/mg DNA, respectively (P less than 0.02). No alterations occurred in the cortical PC precursor pools of choline, phosphocholine, cytidine diphosphocholine, or diacylglycerol. At 15 min after the injection of 32P, the incorporation of isotope into the PC pool was increased in the contralateral kidney when compared with sham-operated controls. The calculated maximal velocities of choline kinase and cholinephosphotransferase were increased subsequent to unilateral nephrectomy, supporting a regulatory role for these enzymes in PC biosynthesis during renal growth.