A marked increase in latency of fetal rat liver UDP-glucuronosyltransferase accompanies the fluidization of the microsomal membrane in the perinatal period.
The activity of rat liver microsomal uridine diphosphate glucuronosyltransferase towards 4-methylumbelliferone (4-MU-UDPGT) increased markedly between day 18 of fetal life and day 1 after birth. This increase in UDPGT activity resulted largely from a gradual increase in the fraction of enzyme activity which was detected after pretreatment of microsomes with digitonin ('latent' activity). The latent fraction of 4-MU-UDPGT activity approached at birth the values obtained for adult rat liver. This perinatal increase in latency of 4-MU-UDPGT activity may be associated with the concurrent fluidization of the microsomal membrane which is observed in the perinatal period.
Kapitulnik
J
J
Department of Pharmacology, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Tshershedsky
M
M
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism; D004072:Digitonin / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D014453:Glucuronosyltransferase / Q000378:metabolism*; D008560:Membrane Fluidity; D008862:Microsomes, Liver / Q000201:enzymology* / Q000648:ultrastructure; D051381:Rats; D011919:Rats, Inbred Strains
D014453:Glucuronosyltransferase; D004072:Digitonin