Incorporation of 32P into phospholipids in vivo during compensatory renal growth

Incorporation of 32P into phospholipids, RNA and DNA was studied in adult male C57BL/GoZgb mice. Left nephrectomy was performed under diethyl ether anesthesia, and the remaining right kidney was excised 10 min to 28 days later. Sham-operated animals were used as controls. 2 h before killing, animals were injected intraperitoneally with 37 kBq (1 microCi) 32P (as sodium orthophosphate) per g of body weight. In the right kidney, incorporation of 32P into total phospholipids, and five phospholipid fractions (phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, diphosphatidylglycerol and sphingomyelin) was increased by 25-35% between 20 and 72 h after uninephrectomy. The incorporation of 32P into RNA showed a similar pattern. However, incorporation of 32P into phosphatidylinositol and phosphatidic acid was already increased 20 min after uninephrectomy, reached a peak about 110-120% above control values 4 h after uninephrectomy, and then slowly returned to the control value at about 84-96 h. These results indicate that an early alteration in phospholipid metabolism, particularly of inositol lipids, may play a role in initiation of compensatory renal growth.