Perinatal development of N-acetyltransferase in hepatic and extrahepatic tissues of guinea pigs.

Hepatic and extrahepatic distribution and the perinatal developmental pattern of p-aminobenzoic acid (PABA)-N-acetyltransferase (E.C.2.3.1.5) in guinea pig liver, lung, and placenta were studied. In adult guinea pigs, kidney and small intestine enzyme specific activities were equivalent to hepatic activity. Lung enzyme activity was about 15% of that in adult liver. No sex differences in hepatic or extrahepatic distribution of enzyme levels were evident. The perinatal development study revealed that fetal as well as neonatal animals are capable of N-acetylation. The peak in liver and lung activity occur between 3 and 8 days after birth. Placenta has about 50% of adult liver activity for PABA-N-acetylation and it declines near term. These data indicate that extrahepatic organs of guinea pigs significantly contribute to PABA-N-acetylation.