[Effect of lindane on the biological effectiveness of estradiol in chickens].

After exposure of sexually immature chickens to lindan in doses of 2.5 to 25.0 mg kg-1 of feeds, the effect of the insecticide on the biological activity of estradiol was investigated. The changes in the effectiveness of estrogen, expressed by an increase of the mass of the oviduct and of the level of serum calcium, were evaluated by means of comparison of animals exposed to the insecticide with a control group that had been applied only the standard hormone dose. Proofs were obtained for the fact that the application of lindan in the quantity of the mentioned doses for 14 days caused a statistically conclusive depression of the biological effectiveness of estrogens. Compared with the control group, the stimulated mass of the oviduct of animals exposed to the insecticide was smaller by 12.7 to 17.1 p. c. and the average concentration of the serum calcium decreased by 8.0 to 27.6 p. c. The results obtained indicate that the influence of lindan already in relatively low concentrations caused significant changes in the effectiveness of exogenous estrogens.