COMPARTMENTAL STUDY OF RAT RENAL PROSTAGLANDIN SYNTHESIS DURING DEVELOPMENT

The biosynthesis of prostaglandins (PGs) from the endogenous and exoge nous precursor, arachidonic acid (AA), in renal papilla, medulla and c ortex from neonatal to adult rats was investigated. Rat renal papilla and medulla incubated in the presence of [1-C-14]AA released radioacti ve PGE(2), PGF(2 alpha) and PGD(2) which increased with age. No radioa ctive prostaglandins were found in the supernatants of renal cortex at any age studied. The amount of total prostaglandins released from the endogenous precursor also increased from 10 to 70 days of age, PGD(2) being the prostaglandin that showed the most important rise. In the c ortex, only PGE(2) release increased with age. Cyclooxygenase (COX) ac tivity was measured in papillary, medullary and cortical homogenates b y using [1-C-14]AA as substrate. Papillary and medullary COX activity increased after 10 days of age and continued to rise up to day 30 ther eafter remaining unaltered until adulthood. Cortical COX activity was very low and decreased with age. These findings indicate the low capac ity of the neonatal rat kidney to synthesize PGs.