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Liver peroxisomes in newborns from clofibrate‐treated rats. II. A biochemical study of the recovery period
Author(s) -
Sartori Claudia,
Stefanini Stefania,
Cimini Annamaria,
Giulio Antonio,
Ceru` Maria Paola
Publication year - 1992
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1016/0248-4900(92)90043-z
Subject(s) - clofibrate , peroxisome , catalase , biology , endocrinology , medicine , membrane fluidity , enzyme , biochemistry , organelle , membrane , gene
Summary— The fatty‐acyl‐CoAβ‐oxidation (FAO) and catalase activities, as well as membrane fluidity of liver peroxisomes of newborns from normal and clofibrate‐treated rats were studied during the recovery period, ie , throughout the first week of postnatal life. In the test animals the enzyme activities, which are significantly higher than controls at birth return to normal levels showing a somewhat different time course with FAO rapidly decreasing to control values within three days but with catalase still higher than controls at day 6. The half‐life and degradation rate (K d ) of FAO are identical to those calculated by us for the whole organelles and to those reported by others for total catalase in normal or clofibrate‐treated adult animals in the presence of catalase inhibitors. Soluble catalase shows turnover values which are similar though not identical to those of FAO, while total catalase has a very long half‐life and a low K d . Peroxisomal membrane fluidity, as determined by fluorescence anisotropy of 1‐anilinonaphthalene‐8‐sulfonate (ANS) bound to purified peroxisomal fractions is higher in tests than in controls, recovering normal values within 6 days. Our results demonstrate that liver peroxisomes of rats prenatally exposed to clofibrate return to control conditions within about 1 week. The turnover parameters of enzymes and the membrane fluidity values are discussed in terms of disposal mechanism(s) for the excess of induced peroxisomes.