Development and Validation of a Fecal Testosterone Biomarker: RESULTS(4)

Analysis of the aqueous component remaining after ether extraction yielded a single large polar peak (the presumably conjugated metabolites were not enzyme hydrolyzable and were not identified). Further HPLC analyses using an in-line ra-diomatic detector on samples from Mus indicated that testosterone made up less than 8% of nonpolar steroids from feces. buy cipro

Animal Validation

Fecal testosterone concentrations increased to 8 times the basal level when animals were given hCG, decreased below basal after surgical castration, and did not change with hCG treatment of castrated mice (Table 2). No gross abnormalities of the testes, such as atrophy or discoloration, were observed.

The preliminary data resulting from field trials demonstrate the utility of this biomarker as an accurate indicator of reproductive condition in a control population. The mean fecal testosterone content of reproductively active males (testes in scrotal position) was 510 ± 32 ng/g feces (n = 86, mean ± SEM), while the fecal testosterone of inactive males (testes in abdominal position) was 380 ± 18 ng/g feces (n = 261, mean ± SEM). Analysis using a one-way ANOVA showed that the difference between the two groups was statistically significant (p < 0.05).

TABLE 2. Testosterone levels in feces after hCG challenge to obtain maximum levels and castration to obtain a minimum level.

Reproductive state n Testosterone* SD
Basal 3 173 39
hCG stimulated 3 1352 60
Castrated 3 52 23

* Values for the amount of unconjugated testosterone extracted represent nanograms testosterone per gram of feces.

This entry was posted in Testosterone and tagged Biomarker, Mus musculus, Peromyscus maniculatus, Testosterone.