Perinatal Activity of Hepatic Gamma-Glutamyltranspeptidase in Rats from Large and Small Litters

Abstract

In rat pups, the activity of hepatic gamma-glutamyltranspeptidase (GGT) is not influenced by the process of labor. Maximum activities are observed prenatally occurring at the 21st day of gestation in fetuses from normal, large litters, but at the 20th day of gestation in fetuses from experimentally reduced litters (2 fetuses per litter). This different developmental pattern may depend on processes of fetal maturation rather than on processes of luteolysis.

Perinatal Glutathione Levels in Liver and Brain of Rats from Large and Small Litters

“…Our results of high hepatic GGT activi ties [Glöckner and Kretzschmar, 1989] and peak rather than low GSH concentrations in newborn rats of full litters at term support the hypothesis of Sulakhe and Lautt [1987] of different main functions of GGT in fetal/ neonatal versus nonproliferating adult liver cells. Further evidence is the existence of dif ferent hepatic GGT isozymes with different affinities towards the substrate and different developmental patterns, suggested by inves tigations of .…”

“…In previous investigations we studied the development of hepatic y-glutamyltranspeptidase (GGT) activity to find out whether this parameter is useful for the characteriza tion of fetal maturation [Glöckner and Kretzschmar, 1989]. In accordance with the literature, maximum activities during onto genesis were found perinatally (after 21 days of gestation before and after labor) if the rat pups belonged to normal full litters (n > 10).…”

“…GSH, oxoproline) rather than high GGT activities are necessary to ensure pro liferation [Hamilos et al, 1989;Vina et al, 1989], Different developmental conditions ex isting between fetuses of full and reduced lit ters differently influence the development of hepatic GGT activities [Glöckner and Kretzschmar, 1989], but not that of hepatic GSH concentrations. Furthermore, in re duced litters the maximum hepatic GSH concentration does not coincide with peri ods of maximum fetal growth (between the 19th and 20th days of gestation) as was found for hepatic GGT activities [Glöckner and Kretzschmar, 1989]. Thus in the perina tal period additional independent regula tions of GGT activity and GSH status might be assumed.…”

“…Pregnant rats (Uje: WIST, 90-120 days old) were obtained and housed under controlled conventional conditions as described elsewhere [Glöckner and Kretzschmar, 1989], In untreated young dams of our colony breed, labor begins in most cases at noon/ afternoon of the 21st day of pregnancy. For determi nation of GSH concentrations in liver and brain dur ing late gestation cesarean section was performed after cervical dislocation of dams with full and re duced litters in the morning of gestational days 19, 20 and 21.…”

“…Experimental reduction of litter size to 2 fetuses/ dam was carried out on the 6th day of pregnancy as described by Glöckner and Kretzschmar [1989].…”