A rapid and sustained increase in the number of microbodies in liver and kidney cells can be induced in male rats by ethyl chlorophenoxyisobutyrate (CPIB), a hypolipidemic drug. This phenomenon permits investigation of several aspects of microbody behavior in experimental conditions. Reversal experiments demonstrate that liver cells revert to normal between 2 and 3 weeks after withdrawal of CPIB and that one of the mechanisms for removal of excess microbodies is their incorporation into structures indistinguishable from lysosomes. In a state of rapid cell division, such as that present during liver regeneration, microbody proliferation apparently occupies a high biological priority. In necrotic or degenerating cells microbody structure remains relatively normal. The increase in microbodies induced by CPIB is inhibited by chloramphenicol. No increase in microbodies occurred in female rats or in chickens, guinea pigs, or rabbits at the dosage used (0.25% in diet). No changes in microbodies were seen in monkey liver. Catalase activity was generally parallel to the numerical response in microbodies. Additional observations suggest that the microbody response to CPIB is not related to hepatomegaly induced by this agent but may be related to the hypolipidemic effect of CPIB, though hypolipidemia per se is not a specific or sufficient cause of microbody proliferation.
The chlorophenyl position isomers of 2,2bis (chlorophenyl) -1,l -dichloroethane (DDD ) produce adrenal cortical atrophy in the dog ( 1 ) and inhibition of steroidogenesis in the ~~ * This investigation was supported by USPHS Grants AM 08188-01 and AM 02767 from Arthritis and Metabolism Section.t Markle Scholar in Academic Medicine.
The process of arousal from hibernation is begun by a temperature rise in the foreparts of the gopher which precedes any rise in oxygen consumption. This is followed by a rapid change of the R.Q. from values near 0.7–1.0 and an acceleration of O2 consumption. The rate of heat production appears to exceed that calculated from the O2 consumption until the arousal process is more than half complete. The probable source of this heat is the store of energy rich compounds in the body. The P/O ratio of liver particles was shown to be identical for the normal and hibernating hamster contrary to what would be predicted from current theory. Perfusion experiments with isolated hearts of rat, normal and hibernating hamster reveals no detectable humoral activity in the blood of hibernating hamster.
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