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Titolo:
INSULIN BUT NOT PROGESTERONE PROMOTES THE BIOSYNTHESIS OF GLYCOGEN INXENOPUS-LAEVIS OOCYTES - IMPLICATIONS ON THE CONTROL OF GLYCOGEN-SYNTHASE BY PHOSPHORYLATION, DEPHOSPHORYLATION
Autore:
DEBAUCHE P; BARAS B; DEVOS P;
Indirizzi:
FAC UNIV NOTRE DAME PAIX,BIOCHIM & PHYSIOL COMPAREES LAB,61 RUE BRUXELLES B-5000 NAMUR BELGIUM
Titolo Testata:
The Journal of experimental zoology
fascicolo: 1, volume: 269, anno: 1994,
pagine: 1 - 11
SICI:
0022-104X(1994)269:1<1:IBNPPT>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
GROWTH FACTOR-I; PROTEIN PHOSPHATASE; GLUCOSE-6-PHOSPHATE PLAYS; ADENYLATE-CYCLASE; OKADAIC ACID; GLUCOSE; ACTIVATION; PURIFICATION; HEPATOCYTES; MATURATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
53
Recensione:
Indirizzi per estratti:
Citazione:
P. Debauche et al., "INSULIN BUT NOT PROGESTERONE PROMOTES THE BIOSYNTHESIS OF GLYCOGEN INXENOPUS-LAEVIS OOCYTES - IMPLICATIONS ON THE CONTROL OF GLYCOGEN-SYNTHASE BY PHOSPHORYLATION, DEPHOSPHORYLATION", The Journal of experimental zoology, 269(1), 1994, pp. 1-11

Abstract

Insulin, the well-known hypoglycemic hormone, mimics progesterone in promoting the resumption of meiosis within the oocyte of Xenopus laevis. Both hormones exert their action through the inhibition of protein kinases arid the activation of protein phosphatases. Because glycogen synthase is an enzyme regulated by a kinases/phosphatases cascade, we investigated the effect of insulin and progesterone on the regulation of glycogen synthesis and glycogen synthase throughout the oogenesis of Xenopus laevis oocytes. In this framework the maximal activity of synthase ''a'' is concomitant with the vitellogenic period characterizedby a drastic increase in the amount df glycogen. Oocyte glycogen synthase is inhibited by cAMP-dependent phosphorylation and stimulated by 20 mM Mg2+. The magnesium effect is inhibited by mu molar concentrations of okadaic acid and suggests that oocyte glycogen synthase is activated by dephosphorylation achieved by protein phosphatase-1. The okadaic acid effect is itself thwarted by the specific inhibitor of proteinkinase A, confirming the role of this kinase in the regulation of glycogen synthase. Finally, working on intact ripe oocytes, we showed that insulin but not progesterone increases glycogen synthesis and glycogen synthase ''a'' activity and lowers the rates of phosphorylation, especially in the glycogen-bound proteins. (C) 1994 Wiley-Liss, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 13/07/20 alle ore 16:54:48