AJP - Renal Physiology, Vol 237, Issue 4 268-F273, Copyright © 1979 by American Physiological Society
Secretion of prostaglandin E2 by rabbit proximal tubules
J. M. Irish 3rd
This study was designed to evaluate prostaglandin secretion from bath to
urine in isolated perfused rabbit proximal tubules. Active prostaglandin E2
(PGE2) secretion occurred along the entire length of the proximal tubule,
but the rate of net secretion was highest in the S2 segment of the proximal
straight tubule. Sixteen percent of the PGE2 secreted in the proximal
straight tubule was metabolized to other products. The PGE2 cell-to-bath
ratio averaged 40 and the tubule fluid-to-bath ratio averaged 3.4. These
findings suggest active transport of PGE2 across the peritubular membrane
and passive movement across the luminal membrane. Indomethacin, probenecid,
para-aminohippurate, and ouabain partially inhibited PGE2 cell accumulation
and net secretion. PGE2 entered the urine of the perfused descending limb
of Henle (DLH), but at a rate two orders of magnitude below that observed
in the S2 segment of the proximal tubule. No evidence of active PGE2
secretion was observed in the DLH. These results suggest that PGE2 is
secreted into the urine at substantial rates by the organic anion transport
system of renal proximal tubules.
