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Comparative urinary androstanes in the great apes
1Zoological Society of San Diego, P.O. Box 120551, San Diego, California 92112, USA. lhagey@ucsd.edu
General and Comparative Endocrinology
|January 22, 2003
Summary
Urinary testosterone is a trace metabolite in great apes, not a reliable indicator of serum levels. Androstane metabolism varies significantly across species, impacting RIA test accuracy.
Area of Science:
- Primatology
- Endocrinology
- Analytical Chemistry
Background:
- Urinary androstanes, including testosterone, are used to assess endocrine function in great apes.
- Previous studies have relied on immunoassays like radioimmunoassay (RIA) for detection.
Purpose of the Study:
- To investigate and compare urinary androstane profiles in seven male great ape species.
- To evaluate the accuracy of RIA for quantifying urinary testosterone by comparing it with mass spectrometry.
Main Methods:
- High-performance liquid chromatography (HPLC) for separation of urinary androstanes.
- Radioimmunoassay (RIA) using testosterone antibodies for detection.
- Nano-spray mass spectrometry (nanoESI-MS) for direct visualization and quantification.
Main Results:
- Testosterone was a dominant urinary peak (85%) only in humans, being a minor component in other apes (24-59%).
- NanoESI-MS revealed testosterone is a trace metabolite in non-human ape urine, despite strong RIA signals.
- A novel testosterone metabolite (delta1- or delta6-testosterone sulfate) was found in all non-human apes.
Conclusions:
- Urinary testosterone measurements via RIA may not reflect serum testosterone levels in great apes.
- Significant interspecies differences in androstane metabolism exist, limiting comparability of RIA results across species.
- Accurate assessment requires advanced techniques like mass spectrometry to differentiate testosterone from other androstanes.