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dc.contributor.authorLim, Paulen_US
dc.contributor.authorHsueh, Aaron J. W.en_US
dc.contributor.authorBremner, William J.en_US
dc.contributor.authorMatsumoto, Alvin M.en_US
dc.contributor.authorTenover, Joyce S.en_US
dc.contributor.authorDahl, Kristine D.en_US
dc.date.accessioned2008-10-17T20:40:09Z
dc.date.available2008-10-17T20:40:09Z
dc.date.issued1987-06en_US
dc.identifier.citationJ Clin Endocrinol Metab. 1987 Jun;64(6):1103-8en_US
dc.identifier.urihttp://hdl.handle.net/1773/4288
dc.description.abstractTesticular function declines with normal aging, while serum immunoreactive LH and FSH levels increase. Since there are reports of an age-related decrease in the ratio of bioactivity to immunoreactivity (B/I ratio) for LH, we used a newly available bioassay for FSH to assess age-associated changes in the bioactivity and B/I ratio of FSH in man. Thirty-nine healthy men (23 young and 16 elderly) had single blood samples drawn. In addition, a subset of these men (12 young and 13 elderly) underwent frequent blood sampling for 24 h, both before and after 7 days of clomiphene citrate (CC) administration. Hourly blood samples from the 24-h sampling were pooled, and these, along with the single samples, were assayed for FSH by an in vitro bioassay system, using estrogen production by immature rat granulosa cells as the end point, and by RIA. Baseline single sample mean FSH, as measured by bioassay, was similar in young and elderly men [386 +/- 98 (+/- SEM) and 342 +/- 77 ng/mL, respectively]. Baseline mean FSH, measured by RIA, was significantly higher (P less than 0.001) in elderly men (234 +/- 31 ng/mL) than in young men (122 +/- 12 ng/mL). The baseline FSH B/I ratio based on single sampling was significantly lower (P less than 0.01) in elderly men (1.4 +/- 0.2) than in young men (2.7 +/- 0.3). In the men given CC and sampled for 24 h, mean bioactive FSH levels increased significantly in both the young (1180 +/- 282 ng/mL) and the elderly (992 +/- 227 ng/mL; P less than 0.01 for both values compared to baseline). Mean FSH by RIA also increased to similar levels in these young (217 +/- 34 ng/mL) and elderly (258 +/- 45 ng/mL) men. The FSH B/I ratio was 4.8 +/- 0.8 in young and 4.7 +/- 1.1 in elderly men after CC administration. We conclude that serum bioactive FSH levels are similar in elderly and young men, suggesting that the age-related decline in testicular function in man cannot be explained by a chronic deficiency in FSH stimulation; elderly men have a lower serum FSH B/I ratio than young men, which may reflect changes in the circulating form of FSH with aging; and administration of CC to young and elderly men increases both bioactive and immunoreactive serum FSH, implying preserved hypothalamic-pituitary responsiveness in the elderly.en_US
dc.language.isoen_USen_US
dc.publisherEndocrine Societyen_US
dc.subjectmale contraceptionen_US
dc.subject5-alpha reductase inhibitorsen_US
dc.subjectandrologyen_US
dc.subjectreifenstein's syndromeen_US
dc.subjectgonadotropinsen_US
dc.subjectcolchicineen_US
dc.subjectspermatogenesisen_US
dc.subjecttestosteroneen_US
dc.subjectklinefelter's syndromeen_US
dc.subject.meshAged, 80 and overen_US
dc.subject.meshAgeden_US
dc.subject.meshClomiphene, pharmacologyen_US
dc.subject.meshEstrogens, biosynthesisen_US
dc.subject.meshBiological Assayen_US
dc.subject.meshHumansen_US
dc.subject.meshFemaleen_US
dc.subject.meshFollicle Stimulating Hormone, blooden_US
dc.subject.meshRadioimmunoassayen_US
dc.subject.meshDose-Response Relationship, Drugen_US
dc.subject.meshAdulten_US
dc.subject.meshGranulosa Cells, metabolismen_US
dc.subject.meshResearch Support, U.S. Gov't, P.H.S.en_US
dc.subject.meshResearch Support, U.S. Gov't, Non-P.H.S.en_US
dc.subject.meshMaleen_US
dc.titleSerum bioactive and immunoreactive follicle-stimulating hormone levels and the response to clomiphene in healthy young and elderly menen_US
dc.typeArticleen_US


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