title: Modulation of gamma-glutamyltranspeptidase activity in rat liver plasma membranes by thyroid hormone.
abstract: 1. In adult male and female rats, liver plasma membrane gamma-glutamyltranspeptidase activities were 16-fold higher in the propylthiouracil (PTU)-induced hypothyroid state than in the control euthyroid state; thyroxine (T4)-replacement resulted in an 80% restoration to control levels. 2. Liver plasma membrane gamma-glutamyltranspeptidase activities were 6.7-fold higher in PTU-induced congenitally hypothyroid rats than in control euthyroid rats; T4-replacement reduced enzyme activities to 37% of control levels. 3. In adult rats, in response to the development and recovery from tri-iodothyronine (T3) excess, liver plasma membrane gamma-glutamyltranspeptidase activities were inversely related to, and out of phase by 12 hr, to the earlier changes in T3. 4. Liver gamma-glutamyltranspeptidase is a thyroid hormone-dependent enzyme.
authors.affiliation: Department of Physiology, College of Medicine, University of Saskatchewan, Saskatoon, Canada.
authors.forename: S J
authors.initials: SJ
authors.lastname: Sulakhe
authors.forename: S T
authors.initials: ST
authors.lastname: Tran
authors.forename: V B
authors.initials: VB
authors.lastname: Pulga
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D005260:Female; D007037:Hypothyroidism / Q000139:chemically induced / Q000188:drug therapy / Q000201:enzymology; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D011247:Pregnancy; D011441:Propylthiouracil; D051381:Rats; D011916:Rats, Inbred F344; D013974:Thyroxine / Q000494:pharmacology* / Q000627:therapeutic use; D014284:Triiodothyronine / Q000494:pharmacology*; D005723:gamma-Glutamyltransferase / Q000378:metabolism*
chemical_list: D014284:Triiodothyronine; D011441:Propylthiouracil; D005723:gamma-Glutamyltransferase; D013974:Thyroxine