PARENT SESSION

2L - Immunotoxicity - genotoxicity - ED
Poster Hall
8:30 AM - Wednesday, 30 April 2003
Chair: Hansen, P.D.¹, ¹

(WEP/107) Effects of methyltestosterone on reproduction in the female Japanese quail (Coturnix coturnix japonica).

Selzsam, Britta¹, Niemann, Lars², Wittfoht, Werner¹, Chahoud, Ibrahim¹, ¹ Institute for Clinical Pharmacology and Toxicology, Dep. of Toxicology, Berlin, Germany² Federal Institute of Risk Assessment, Berlin, Germany

ABSTRACT- In a one-generation study the synthetic androgenic hormone methyltestosterone (MT) was administered to adult Japanese quail (12 pairs per group) via their diet at dose levels of 10, 50 and 110 ppm for a period of three weeks to characterize endocrine and other toxic effects on reproduction in birds. Reproductive performance was severely affected in the groups receiving 50 and 110 ppm MT. The egg laying rate was slightly reduced in the low dose group, whereas the observed suppression at the intermediate (89 eggs) and top dose levels (24 eggs) vs control group (232 eggs in total) was significant. This effect was not only related to the dose administered but also to the duration of treatment. Furthermore the percentage of fertile eggs was also reduced, irrespective of the total amount of eggs layed. Reliable assessment of other reproduction-related parameters was not feasible at the two upper dose levels due to the dramatic reduction in the number of eggs whereas the low dose group was not significantly different from the control. At sacrifice, the serum estradiol and testosterone concentrations were measured in 11 hen per group using commercial human EIA testkits. Mean estradiol was suppressed in the mid (80,1±2,6pg/ml) and high dose groups (74,2±18,1pg/ml) as compared to the control (131,3±29,5 pg /ml). Testosterone was also significantly depressed in both dose groups (MED: 0,4±0,1pg/ml and HIGH: 0,3±0,1 pg/ml vs control :1,1±0,4 pg/ml). In conclusion, methyltestosterone had an adverse effect on the reproduction in the adult female Japanese quail. An influence on the endocrine negative feed back system of the hypothalamus-hypophysis- gonade-axis was suggested.

Key words: quail, reproduction, egg-laying, sex steroids