ISSN:
1432-1912
Keywords:
Perfused Liver
;
Hexobarbital Metabolism
;
Microsomal Mixed Function Oxidase
;
NAD Glycohydrolase
;
Cytochrome b5
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Livers from fed and starved rats were perfused with either rat blood, washed bovine erythrocytes suspended in Eagle minimal essential medium, or the same medium without erythrocytes. The activity of microsomal mixed function oxidase under different perfusion conditions was estimated in the intact liver by following the disappearance of hexobarbital from the perfusion medium. Half-lives of 9 and 29 min were determined in perfusion systems with and without erythrocytes, respectively. They were 70% greater in livers from rats starved for 20 h. Identical half-lives were determined in perfusions with rat blood or washed erythrocytes suspended in the synthetic medium. Testosterone inhibited hexobarbital metabolism when added at an equimolar concentration of 0.5 mM. However, no significant inhibition could be detected with 1 mM hydrocortisone. Furthermore, the porphyria—inducing agent allylisopropyl-acetamide markedly inhibited hexobarbital metabolism prior to decreasing the level of cytochrome P 450. Microsomal cytochrome b5, cytochrome P 450 and NADPH cytochrome c reductase were stable during 4 h of perfusion in media containing erythrocytes but their levels were lower by 20, 40 and 45%, respectively, after perfusion with the erythrocyte-free medium. However, in the latter medium the specific activity of NAD glycohydrolase in microsomes was 35% greater. The stability of these proteins was compared with their turnover in vivo and with the morphology of the perfused livers at the light and electron microscopic levels.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00501411
