scholarly journals Changes in ornithine decarboxylase and antizyme activities in developing mouse brain

1988 ◽  
Vol 250 (3) ◽  
pp. 797-803 ◽  
Author(s):  
H Onoue ◽  
S Matsufuji ◽  
M Nishiyama ◽  
Y Murakami ◽  
S Hayashi

A macromolecular inhibitor to ornithine decarboxylase (ODC) present in mouse brain was identified as ODC antizyme [Fong, Heller & Canellakis (1976) Biochim. Biophys. Acta 428, 456-465; Heller, Fong & Canellakis (1976) Proc. Natl. Acad. Sci. U.S.A. 73, 1858-1862] on the basis of kinetic properties, Mr and reversal of its inhibition by antizyme inhibitor. The brain antizyme, however, did not cross-react immunochemically with any of seven monoclonal antibodies to rat liver antizyme. ODC activity in mouse brain rapidly decreased after birth, in parallel with putrescine content, and almost disappeared by 3 weeks of age. Free antizyme activity appeared shortly after birth and increased gradually, whereas ODC-antizyme complex already existed at birth and then gradually decreased. Thus total amount of antizyme remained about the same throughout the developmental period in mouse brain. In addition to ODC-antizyme complex, inactive ODC protein was detected by radioimmunoassay in about the same level as the complex at 3 weeks of age. Upon cycloheximide treatment, both free ODC activity and ODC-antizyme complex rapidly disappeared, although free antizyme and the inactive ODC protein were both quite stable.

1982 ◽  
Vol 204 (3) ◽  
pp. 647-652 ◽  
Author(s):  
K Fujita ◽  
Y Murakami ◽  
S Hayashi

A macromolecular factor that inhibits the activity of the antizyme to ornithine decarboxylase (ODC) was found in rat liver extracts. The factor, ‘antizyme inhibitor’, was heat-labile, non diffusable and of similar molecular size to ODC. The antizyme inhibitor re-activated ODC that had been inactivated by antizyme, apparently by replacing ODC in a complex with antizyme. Therefore the antizyme inhibitor can be used to assay the amount of inactive ODC-antizyme complex formed in vitro. When assayed by this method, the complex was shown to be eluted before ODC from a Sephadex G-100 column. Significant increase in ODC activity was observed when the antizyme inhibitor was added to crude liver extracts from rats that had been injected with 1,3-diaminopropane to cause decay of ODC activity, suggesting the presence of inactive ODC-antizyme complex in the extracts.


1984 ◽  
Vol 218 (2) ◽  
pp. 557-562 ◽  
Author(s):  
K Fujita ◽  
S Matsufuji ◽  
Y Murakami ◽  
S Hayashi

Antizyme to ornithine decarboxylase (ODC) and ODC-antizyme complex were both present in liver cytosols of starved rats. The antizyme was identified by its molecular weight, kinetic properties, formation of a complex with ODC, and reversal of its inhibition by antizyme inhibitor. The average amount of antizyme in liver cytosols of starved rats was 0.1 unit/mg of protein, roughly corresponding to basal hepatic ODC activity in rats fed ad libitum. The presence of ODC-antizyme complex was detected by using antizyme inhibitor. These results indicate that antizyme participates in the regulation of ODC activity in vivo under physiological conditions.


1972 ◽  
Vol 127 (4) ◽  
pp. 721-731 ◽  
Author(s):  
Marshall C. Middleton ◽  
Deryck G. Walker

1. Two forms of hepatic pyruvate kinase, designated type L and type M, were distinguished on the basis of kinetic, chromatographic, electrophoretic and immunological criteria. They were partially purified and their properties compared with each other and with the purified enzyme from skeletal muscle. 2. In contrast with type L, the type M enzyme showed no marked evidence of co-operative interactions with phosphoenolpyruvate and was not stimulated by fructose diphosphate. 3. The activity profiles of type L and type M enzymes were determined in developing rat liver by utilizing differences in the kinetic properties of the two forms. The high activity of type M enzyme in the early foetal rat decreased in late gestation and immediately after birth to reach a low value, which remained essentially constant for the remainder of the developmental period. The activity of type L enzyme, in contrast, was low in the early foetal and neonatal liver but increased markedly at the onset of weaning. 4. Possible roles of the two forms of hepatic pyruvate kinase in the control of glycolysis and gluconeogenesis are discussed.


1973 ◽  
Vol 51 (4) ◽  
pp. 482-485 ◽  
Author(s):  
Beng T. Ho ◽  
Dorothy Taylor ◽  
K. E. Walker ◽  
William M. McIsaac

6-Methoxy-1,2,3,4-tetrahydro-β-carboline (6-MeO-THBC), which specifically elevates serotonin in the brain, exerted no significant effects on mouse brain monoamine oxidase, rat brain tryptophan hydroxylase, and rat liver tryptophan pyrrolase. There was a marked activation of rat plasma and liver 5-hydroxytryptophan decarboxylase and a concomitant increase of serotonin levels in the two tissues. 6-MeO-THBC did not alter the endogenous tryptophan levels in rat plasma and brain. A significant facilitation of the uptake of [3-14C]-5-hydroxytryptophan was observed in brains of mice treated with 6-MeO-THBC. The possibility that the increased serotonin was derived from 6-MeO-THBC itself was ruled out.


2020 ◽  
Author(s):  
Miguel A. Gama Sosa ◽  
Rita De Gasperi ◽  
Gissel M. Perez ◽  
Patrick R. Hof ◽  
Gregory A. Elder

Sign in / Sign up

Export Citation Format

Share Document