Sexual differences in the effects of castration on body and thymus weights in albino rats

Abstract

I n this experiment a study was made of sexual differences in the effects of castration on the body and thymus weights of albino r8ts.I MATERIALS AND METHODSMale and female albino rats were castrated at 50 days of age and autopsied at 60 days. One hundred and sixty-nine rats from 36 litters were used. Four additional animals were excluded because of respiratory infections noted at the time of autopsy. All were born in our breeding colony and originated from a Sprague-Dawley, Inc., stock.The results include 43 castrated males and 41 sham operated males, 44 spayed females and 42 sham operated females. The brothers and sisters of each litter were distributed among experimental and control animals to allow for deviations in growth rate that might result from littermate relationship.The males were castrated through a mid-ventral incision and the females through two dorsal incisions. I n the sham operations the gonad was lifted through the incision and replaced in the animal. Experimental animals and their littermate controls were kept in the same cages and were maintained on the same diet.'I want to thank Dorothy W. Plagge f o r her many helpful suggestions and criticisms throughout the writing of this report. I also take pleasure in acknowledging the help of Dr. B. A. Schneider in the statistical aiidpsis of the data. 237