Perinatal development of hepatic microsomal mixed function oxidase activity in swine

Developmental Changes in Hepatic Esterase Activity towards Chloramphenicol Succinate and Its Michaelis-Menten Constant of Liver, Kidney and Lung in Human

“…However, the several increases in Vmax may reflect an increase in the number of enzyme proteins. A similar pattern of devel opment in Km and Vmax has been reported previously on both enzyme activity [14,15] and hepatic uptake process [16,17]; Vmax increased grad ually with postnatal age whereas Km values remained constant. Therefore, it was concluded that the liver plays the most important role in hydrolysis of chloramphenicol succinate when the weight of the organ is taken into con sideration.…”

Hepatic and pulmonary enzyme activities in horses

“…[31][32][33][34] In others, the specific content of cytochrome P450 does not vary as widely in young animals as in adults (dog, monkey, swine, and horses). 28,30,[35][36][37][38][39] When comparing the cytochrome P450 content of adults, variation among species appears to be great, with rabbits 31 expressing twofold higher amounts of cytochrome P450 than horses, 28 sheep, 32,30,40,41 goats, 34 and rats. 16,33,40 In all species, hepatic cytochrome P450 content varies from twofold (goats) to as much as 20-fold (sheep) higher than in pulmonary tissue from young animals.…”

Developmental Aspects of the Hepatic Cytochrome P450 Monooxygenase System

“…In contrast to the substantial xenobiotic monooxygenase activity exhib ited by midgestational human fetal liver preparations, studies of nonprimate fetal liver have not revealed comparable activity (34,53,55,66), even in animals that achieve considerable maturity in utero (55) or experience a long gestational period (34). Although miniscule, catalytic activity and/or components of the monooxyge nase system are measurable in liver from second or third trimester fetal swine (34,(58)(59)(60), guinea pig (55), rat (67), and mouse (50).…”

“…The capacity of hepatic tissue to catalyze the xenobiotic monooxygenase reaction is presented schematically as a function of the age of the animal from which liver was obtained in Figure 1. The various developmental sequences depicted in Figure I apply to different species, including rat (41)(42)(43)(44)(45)(46)(47)(48), mouse (49,50), rabbit (39,(51)(52)(53), hamster (54), guinea pig (38,55,56), opossum (57), swine (34,(58)(59)(60), and ferret (61). The figure was compiled to emphasize the similarities, rather than the differences, in separate studies.…”

“…Various components and catalytic activities that have been associated with the hepatic monooxygenase complex (cytochrome P450, NADPH-cytochrome P450 reductase, NADPH-cytochrome c reductase, NADPH-oxidase, cytochrome bs, and cytochrome bs reductase) have been studied singly or in combination in livers of developing rat (41,42,47,48), rabbit (52,53), swine (34,60), guinea pig (55) and ferret (61). In general, the developmental sequences for cytochrome P450 and NADPH-cytochrome P450 reductase resemble closely the developmental patterns for monooxygenase activity depicted in Figure 1.…”