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Serum testosterone bioassay evaluation in a large male cohort
Author(s) -
Need Eleanor F.,
O’Loughlin Peter D.,
Armstrong David T.,
Haren Matthew T.,
Martin Sean A.,
Tilley Wayne D.,
Wittert Gary A.,
Buchanan Grant
Publication year - 2010
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.2009.03595.x
Subject(s) - bioassay , testosterone (patch) , endocrinology , medicine , cohort , androgen , biology , hormone , genetics
Summary Objective To assess if a cell‐based readout of androgen action in serum demonstrates a closer association with recognized classical parameters of androgen action in men than current measures of serum testosterone (T). Design To develop, validate and utilize a mammalian cell‐based assay to measure specifically bioactive T and determine if this measure is a physiologically relevant fraction of serum T. Measurements and participants We have developed a specific serum T bioassay using human prostate cancer cells. A rapid 5‐min exposure to 100% serum followed by serum withdrawal confers specificity of the assay to serum T and provides sufficient sensitivity to measure T in male serum samples. Matrix effects were experimentally discounted as a confounding issue. A total of 960 male serum samples from the Florey Adelaide Male Ageing Study (FAMAS) with previous comprehensive cohort data and serum measurements were utilized. Results Bioassay T measurement in the 960 FAMAS serum samples returned a median of 10·7 nmol/l (1·7–45·4), and was most closely related to immunoassayed total T, but not immunoassayed bioavailable T or calculated free T. Immunoassayed total T demonstrated a positive association with isometric grip‐strength ( R 2 = 0·127, P < 0·001), self‐reported sexual desire ( R 2 = 0·113, P < 0·001) and erectile function ( R 2 = 0·085, P < 0·05) while bioassay T did not. Conclusions While cellular bioassays offer a rapid and sensitive means of identifying the androgenic potential of complex environmental compounds, the utility of such assays in defining a clinically relevant fraction of serum T distinct from total T needs further investigation.