Bean G H, Lowenstein L M
J Clin Invest. 1978 Jun;61(6):1551-4. doi: 10.1172/JCI109075.
Cellular membrane synthesis occurs during normal and stimulated renal growth. Choline in the kidney is utilized as a precursor for membrane synthesis via the choline kinase reaction. We investigated choline phosphorylation during normal and stimulated renal growth. Rapidly growing neonatal rat kidneys contained relatively high levels of choline kinase activity (61 pmol phosphorylcholine/min per mg protein). Choline kinase activity and phosphorylcholine production then fell gradually over the 1st mo of life; by 1 mo phosphorylcholine production was 34 pmol phosphorylcholine/min per mg protein. Choline kinase activity increased by 27% (P less than 0.001) in 28-day-old rats when renal growth was stimulated by contralateral nephrectomy; the increase occurred within 2 h after surgery. Thus, changes in the activity of this important enzyme in the initiation of membrane synthesis is associated both with normal renal development and with adaptation to nephron loss. The findings further suggest that the cell membrane may be involved in the initiation of compensatory renal growth.
细胞膜合成发生在正常和受刺激的肾脏生长过程中。肾脏中的胆碱通过胆碱激酶反应被用作膜合成的前体。我们研究了正常和受刺激的肾脏生长过程中的胆碱磷酸化。快速生长的新生大鼠肾脏含有相对较高水平的胆碱激酶活性（61皮摩尔磷酸胆碱/分钟每毫克蛋白质）。胆碱激酶活性和磷酸胆碱生成量在出生后的第1个月逐渐下降；到1个月时，磷酸胆碱生成量为34皮摩尔磷酸胆碱/分钟每毫克蛋白质。当对侧肾切除刺激肾脏生长时，28日龄大鼠的胆碱激酶活性增加了27%（P<0.001）；这种增加在手术后2小时内就出现了。因此，这种重要酶在膜合成起始过程中的活性变化与正常肾脏发育以及对肾单位丢失的适应都有关。这些发现进一步表明细胞膜可能参与了代偿性肾脏生长的起始过程。
