Prostaglandin synthesis by glomeruli isolated from rats with glycerol-induced acute renal failure.

Abstract

In vitro PG synthesis by glomeruli isolated from rats with glycerol-induced acute renal failure (ARF) was measured by radiometric high performance liquid chromatography after incubation with [14C]arachidonic acid and radioimmunoassay (RIA). The four PGs, 6-keto-PGF1 alpha, TXB2, PGF2 alpha, and PGE2 were each synthesized by glomeruli from both control and treated rats but the synthesis rates were greater after glycerol. This increase was not apparent 1 hour after injection but, at 24 hours, all PGs were produced in greater amounts by glomeruli of treated rats. Thus, we studied PGE2, PGE2 alpha, and TXB2 synthesis by glomeruli at various time intervals after induction of ARF using direct RIA, PGF 2 alpha and TXB2 synthesis were greater only at 24 hours and only in the presence of arachidonic acid, whereas PGE2 synthesis was greater at 24 hours, irrespective of arachidonic acid, but at 48 hours only with arachidonic acid. The stimulatory effect of arachidonic acid was always greater in glycerol-treated than in control rats for these three PGs in the later period, whereas a significant decrease for PGE2 was observed at 1 hour. The late increase in PG synthesis may be due to stimulation of the renin-angiotensin system since it was abolished in rats pretreated for 48 hours with captopril. A late increase in PG synthesis by the papilla of the treated rats also was observed. We concluded that any increase in the glomerular production of vasoconstrictor PGs could contribute to the maintenance of acute renal failure, whereas the early fall in the stimulatory effect of arachidonic acid on PGE2 synthesis could play a role in its initiation.