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Different thermal behavior of neonatal hepatic and cerebral 3‐hydroxy‐3‐methylglutaryl‐CoA reductase
Author(s) -
Ramirez H.,
Alejandre M. J.,
Segovia J. L.,
GarciaPeregrin E.
Publication year - 1981
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02535055
Subject(s) - reductase , microsome , medicine , endocrinology , cholesterol , lipidology , clinical chemistry , chemistry , biology , enzyme , biochemistry
The Arrhenius plots of hepatic and cerebral 3‐hydroxy‐3‐methylglutaryl‐CoA reductase activity were studied in neonatal chicks fed with a standard diet. Supplementation of the diet with 2% cholesterol from hatching has no effect on the thermal characteristics of the brain enzyme. The Arrhenius plot of brain reductase was practically similar to that found in control chicks. However, hepatic reductase was inhibited by cholesterol feeding. Dietary cholesterol increased the cholesterol/lipidic phosphorus molar ratio in liver microsomes, whereas no significant differences were observed in brain microsomes. These results are in agreement with the hypothesis that activity of hepatic reductase is regulated by the fluidity of microsomal membrane and show that cholesterol feeding does not alter the fluidity of microsomal membranes in neonatal chick brain having, thus, no effect on the thermal behavior of cerebral reductase.