Zonal heterogeneity of prostaglandin and thromboxane release in the dog kidney

The release of prostaglandin(PG) and thromboxane(TX) was examined in the six different areas of the normal dog kidney, i.e., renal arterial and venous strips(RA and RV), superficial and deep cortical slices(SC and DC) and outer and inner medullary slices(OM and IM). These tissues were incubated in Krebs-bicarbonate buffer(pH 7.4, 37 degrees C), and the released PGE2, PGF2 alpha, 6-keto-PGF1 alpha and TXB2(as stable metabolites of PGI2 and TXA2, respectively) were determined by radioimmunoassay. In RA, RV, SC and DC, 6-keto-PGF1 alpha was predominant, however, there were no quantitative differences between RA and RV, or SC and DC. The release of 6-keto-PGF1 alpha reached a maximum in IM, similar to findings on the release of PGE2 and PGF2 alpha. The release of TXB2 was uniform in OM and IM. The amount of PGE2, PGF2 alpha, 6-keto-PGF1 alpha and TXB2 released from IM was 2800, 400, 60 and 50 times higher, respectively, than the extent of the release from the cortical slices. These results suggest that PGI2 as well as PGE2 and PGF2 alpha, may be involved in renal PG, and that TXA2 is biosynthesized in the normal dog kidney.