title: Chronopharmacologic aspects of hexobarbital oxidation rate in rats.
abstract: Circadian variations of hexobarbital oxidation rate in rat liver and the relationship to serum corticosterone levels were determined in 324 animals subjected to different lighting regimen and feeding schedules.--Rats maintained under standard light/dark conditions and with free access to food showed a significant circadian hexobarbital oxidase rhythmicity. Inversion of the light/dark cycle and time feeding was followed by significant changes of the 24-h means of hexobarbital oxidation rate as well as of the shape and phasing of the circadian pattern. The animals' response to the experimentally altered environmental conditions did not reveal a predictable relationship between the shape and phasing of the rhythmic patterns of liver hexobarbital oxidase activity and of corticosterone levels in blood serum; the rats subjected to timed feeding showed decreased levels of corticosterone whereas the hexobarbital oxidation rate of the liver was increased.
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism; D000818:Animals; D002940:Circadian Rhythm; D003345:Corticosterone / Q000097:blood; D004435:Eating; D006591:Hexobarbital / Q000378:metabolism*; D008029:Lighting; D008099:Liver / Q000201:enzymology; D008297:Male; D010084:Oxidation-Reduction; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
chemical_list: D006591:Hexobarbital; D000429:Alcohol Oxidoreductases; C021353:hexobarbital oxidase; D003345:Corticosterone