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The circadian cycles of plasma corticosterone and adrenal cholesteryl esters in the normal and EFA‐deficient female rat
Author(s) -
Young Angela K.,
Walker Brian L.
Publication year - 1978
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02533396
Subject(s) - corticosterone , medicine , endocrinology , chemistry , cholesteryl ester , corn oil , glucocorticoid , circadian rhythm , fatty acid , hormone , cholesterol , biochemistry , biology , lipoprotein
In female rats subjected to a 12 hr light‐12 hr darkness schedule and fed a semipurified diet containing 10% corn oil, plasma corticosterone concentration showed a monophasic circadian cycle with minimum and maximum concentrations at the start of the light and dark periods, respectively. Adrenal total cholesteryl ester concentration was inversely related to plasma corticosterone, as were those of several of the individual esters; changes in cholesteryl ester concentration appeared to follow rather than precede changes in plasma corticosterone. There was preferential depletion of the cholesteryl esters of 18∶1, 18∶2ω6, and 20∶4ω6 during glucocorticoid secretion. [Abbreviations: EFA, essential fatty acid (s);X:YωZ, fatty acid with X carbon atoms and Y olefinic bonds with the terminal double bond Z carbon atoms from the methyl group.] In female rats fed hydrogenated coconut oil (EFA‐deficient), a monophasic cycle for plasma corticosterone was also observed, but the peak was much broader than that recorded for rats fed corn oil, although minima and maxima occurred at similar times for the two groups. No significant cycle of adrenal total cholesteryl esters was evident in the deficient rats, but the 20∶3ω9 and 22∶3ω9 esters did decrease significantly during the period of high plasma corticosterone concentration. Preferential net decreases in adrenal cholesteryl esters during corticosteroidogenesis were more apparent in normal than in EFA‐deficient rats.