Long-lasting effect of single ecdysone injections in newborn rats

Single injections of ecdysone to newborn rats were followed by increases in the weights of the adrenals and decreases in the weights of the thymuses in the adults. No change was registered in body weights and in the weights of the gonads. The plasma androsterone levels seemed to decrease; however, the interindividual differences proved to be too great to draw definite conclusions.