Deficiency in 15-hydroxyprostaglandin dehydrogenase activity after unilateral ureteral obstruction of the dog kidney

In the present study, metabolism of prostaglandins (PGs) by 15-hydroxyprostaglandin dehydrogenase (15-OH PGDH) was investigated in dog kidneys with ureteral obstruction. After 24 hr of ureteral obstruction, the obstructed kidney and the contralateral kidney were removed and the cytosolic fractions (105,000 X g), enriched in 15-OH PGDH, were prepared from the cortex and medulla. 15-OH PGDH activity was estimated by radiometric assays of the metabolism of [3H]PGE2 and [3H]prostacyclin. Cortical 15-OH PGDH activity decreased by greater than 50% in the ureter-obstructed kidney as compared to the contralateral kidney. Similar results were obtained by estimating the stereo-specific release of tritium from position 15 using 15-[3H]PGF2 alpha as substrate. In contrast to the cortex, there were no differences in 15-OH PGDH activity found in the medulla of the obstructed and contralateral kidneys. Because the cortex contains higher levels of 15-OH PGDH activity, the deficiency in that site may contribute to the elevated levels of PGs in renal venous blood during ureteral obstruction.