Reports

Circadian Pattern of Plasma 17-Hydroxycorticosteroid: Alteration by Anticholinergic Agents

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Science  17 Mar 1967:
Vol. 155, Issue 3768, pp. 1421-1422
DOI: 10.1126/science.155.3768.1421

Abstract

Atropine, administered to cats just prior to the time of the expected circadian rise in levels of 17-hydroxycorticosteroid in plasma, blocks this rise. Atropine does not alter this circadian pattern when administered at other times in the circadian cycle. Results similar to those obtained with atropine have been observed with short-acting barbiturates. Dibenzyline administered just prior to the time of the expected circadian rise is ineffective in blocking this rise. These findings support the hypothesis that the circadian pattern of plasma 17-hydroxycorticosteroid levels reflects activation, by the central nervous system, of the hypothalamicpituitary-adrenal axis during a "critical time period" in the circadian cycle.