Plasma Esterase Development in the Perinatal Lamb

Abstract

Ovine plasma cholinesterase and nonspecific esterase activities were determined during the last 45 days of fetal development and first 48 h of extrauterine life and compared to adult activities. Marked differences in the development pattern of these enzymes were found. Fetal plasma cholinesterase activity increased between 102 and 112 days gestation to approximately twice adult values and thereafter progressively decreased to adult levels at 48 h postpartum. In contrast, fetal nonspecific esterase activity at 102 days gestation was only about 8% of the adult activity; a steady increase in this activity was found from 102 days gestation to term. From term to 48 h postpartum there was a marked increase of nonspecific esterase activity but the activity at 48 h was still only about 25% of the adult value.