Relation Between Sex Hormones and Changes in Susceptibility of Domestic Norway Rats to Alpha-Naphthyl Thiourea.

Summary In order to determine whether or not actual pubertal changes are responsible for the great decrease in resistance to ANTU observed about the time of puberty, 20 domestic Norway rats were castrated at an early age and given ANTU after reaching an age of 100 days or more. The experimental rats died from doses in the same range as the controls. A second group of 29 suckling rats received daily injections of testosterone or estrone. Both experimental animals and their controls were then given ANTU when they were 35-40 days old. No significant difference in the susceptibility was found. It is, therefore, concluded that the onset of sexual maturity coincides with the decrease in resistance to alpha-naphthyl thiourea but does not produce it.