Circadian studies on succinic dehydrogenase pantothenate and biotin of rodent adrenal

¹ Histochemistry Laboratory, Department of Physiological Chemistry, and Division of Cancer Biology, Department of Pathology, University of Minnesota Medical School, Minneapolis, Minnesota

Coenzyme A concentration and the activity of the succinic dehydrogenase system in rodent adrenals are both circadian periodic functions; both apparently can be synchronized with a 24-hour periodic regimen of alternating light and darkness. Such light-synchronized periodicity analysis reveals that circadian changes in succinic dehydrogenase activity are roughly in phase with changes in serum corticosterone and, perhaps, also in phase with the corticosterone rhythm of the adrenal itself. The circadian rhythm of adrenal CoA, in turn, shows a significant phase difference when compared either to corticosterone concentration or to the activity of the succinic dehydrogenase system. Circadian periodic changes in total biotin concentration in adrenals of rats and mice were not detected.