A mathematical method for estimating paired testes weight from in situ testicular measurements in three species of hamster.

Linear regression analysis was used to determine the correlation between testicular volume (calculated from measurements of length and width) and weights of paired testes. Line equations that can be used to predict weights of paired testes from the volume of one or both testes are given for three species of hamster (Mesocricetus auratus, Mesocricetus brandti, and Phodopus sungorus sungorus). Because these parameters are highly correlated (r greater than or equal to 0.97), the line equations provide a highly reliable means of estimating weights of paired testes from in situ surgical measurements. Weights of testes predicted in this manner are highly correlated with actual weights of paired testes (r greater than or equal to 0.96). The surgical method for measurement of the gonads is also described. This technique for estimating paired testicular weight allows considerable reduction in the number of animals required for long-term experiments and also permits longitudinal studies of individual animals.