Factors related to decreased testosterone concentrations in the peripheral circulation of the maturing male chicken ( Gallus domesticus) fed aflatoxin

Abstract

Nine-week-old male Leghorn chickens were fed a control diet or feed containing 10 ppm aflatoxin for 3 weeks. A collagenase-dispersed testicular cell assay was used to evaluate the ability of the testes to produce testosterone in vitro in response to stimulation by exogenous luteinizing hormone (LH). Blood testosterone levels in the peripheral circulation of control males were higher ( P < 0.05) than in males fed aflatoxin. However, no treatment differences were found in the concentration of testosterone in the testicular vein immediately prior to entering the peripheral circulation, nor were there differences between treatments in the capacity of collagenase-dispersed testicular cells to produce testosterone. The percentage of free testosterone in the peripheral circulating blood was significantly higher in aflatoxin-treated males than in controls. This would support the contention that the primary effect of aflatoxin on circulating levels of testosterone is not one of direct inhibition of the ability of the testicular cells to produce testosterone but rather a change in the rate of clearance of testosterone from the blood.