title: Appearance of a nonfunctional isozyme of hepatic glycogen synthase in late gestation.
abstract: Glycogen levels, glycogen synthase activities, and glycogen synthase protein levels were determined in liver tissues obtained from 14- to 19-day-old fetal mice, newborn mice, and adult mice. The results of these experiments demonstrate a significant increase in the quantity of hepatic glycogen synthase beginning at Day 17 of gestation and reaching adult levels at birth. However, during the same time period, there is a dramatic decrease in total glycogen synthase activity suggesting that the accumulating glycogen synthase molecules are unable to transfer UDP-glucose to glycogen. These inversely coordinated changes in the quantity and activity of glycogen synthase are consistent with the suggestion that glycogen synthesis in the near-term fetal mouse is being maintained by preexisting enzyme, while accumulating enzyme molecules may represent a quiescent isozyme.
authors.affiliation: Department of Anatomy and Cell Biology, University of Cincinnati, Ohio.
authors.forename: S D
authors.initials: SD
authors.lastname: Hsu
authors.forename: S R
authors.initials: SR
authors.lastname: Jaspers
authors.forename: B B
authors.initials: BB
authors.lastname: Davis
authors.forename: R R
authors.initials: RR
authors.lastname: Cardell
authors.forename: T B
authors.initials: TB
authors.lastname: Miller
authors.forename: R L
authors.initials: RL
authors.lastname: Drake
mesh_terms: D000375:Aging / Q000378:metabolism; D000818:Animals; D005260:Female; D005865:Gestational Age; D006006:Glycogen Synthase / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism*; D008099:Liver / Q000196:embryology / Q000201:enzymology*; D051379:Mice; D008813:Mice, Inbred ICR; D011247:Pregnancy
chemical_list: D007527:Isoenzymes; D006006:Glycogen Synthase