PERINATAL DEVELOPMENT OF RAT LIVER AND KIDNEY ESTERASES

The perinatal development of the esterases of rat liver and kidney was examined quantitatively by pH-stat titrimetric analysis and qualitatively by starch gel electrophoresis. Low aliesterase activity was found in prenatal tissues. At birth, the renal esterases showed a marked increase, a level 40 per cent higher than that observed in adult male kidney being detected at day 0. In contrast, hepatic esterase activity rose slowly from birth until day 14 of postnatal life when it increased rapidly, exceeding the adult level by 95 per cent at day 28. After the first month, the activity in both tissues dropped slowly to the usual adult level. Electrophoretic investigation of the perinatal development of hepatic and renal esterases showed that the increased enzyme activity was predominantly of microsomal origin. © 1969.