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Loss of circadian rhythmicity in blood testosterone levels with aging in normal men

Show simple item record Prinz, Patricia N. en_US Bremner, William J. en_US Vitiello, Michael V. en_US 2008-10-17T20:41:08Z 2008-10-17T20:41:08Z 1983-06 en_US
dc.identifier.citation J Clin Endocrinol Metab. 1983 Jun;56(6):1278-81 en_US
dc.description.abstract Previous studies concerning the relationship of serum testosterone levels to aging in normal men have yielded apparently inconsistent results. Studies performing blood sampling in the morning have often shown an age-related decrease in testosterone levels, while those using afternoon samples have failed to show such a decrease. These results suggested to us the possibility that the circadian rhythm in serum testosterone levels might be altered with normal aging in men. Hourly blood samples were obtained for 24 h from 1 young (mean age, 52.2 yr) and 12 old (mean age, 17 yr) healthy men. Total testosterone levels were measured by RIA. The circadian rhythm in serum testosterone levels found in normal young men was markedly attenuated or absent in healthy elderly men; the early morning rise in testosterone levels characteristic of young men was not present in old age. Mean testosterone levels for the entire 24-h day were lower in healthy old men than in young men. These results demonstrate a clear decrease in serum testosterone levels in healthy old men compared to those in young men and provide an explanation for the inability to demonstrate an age-related decline in testosterone levels in earlier studies using serum samples obtained in the afternoon. en_US
dc.language.iso en_US en_US
dc.publisher Endocrine Society en_US
dc.subject andrology en_US
dc.subject 5-alpha reductase inhibitors en_US
dc.subject gonadotropins en_US
dc.subject klinefelter's syndrome en_US
dc.subject testosterone en_US
dc.subject reifenstein's syndrome en_US
dc.subject male contraception en_US
dc.subject spermatogenesis en_US
dc.subject colchicine en_US
dc.subject.mesh Humans en_US
dc.subject.mesh Comparative Study en_US
dc.subject.mesh Middle Aged en_US
dc.subject.mesh Research Support, U.S. Gov't, P.H.S. en_US
dc.subject.mesh Male en_US
dc.subject.mesh Adult en_US
dc.subject.mesh Testosterone, blood en_US
dc.subject.mesh Research Support, U.S. Gov't, Non-P.H.S. en_US
dc.subject.mesh Aging en_US
dc.subject.mesh Circadian Rhythm en_US
dc.subject.mesh Aged en_US
dc.title Loss of circadian rhythmicity in blood testosterone levels with aging in normal men en_US
dc.type Article en_US

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