Optimization and Standardization of Male Gonad Weight Determinations in Rats

Abstract

In order to develop an optimal method for measuring male gonad weight, one that is both statistically dependable (i.e. not subject to wide fluctuations within similarly treated groups) and appropriate with respect to end uses of data, testis, epididymis, and epididymal fat pad weights were obtained from normal adult male rats and subjected to statistical analyses. The results underscore the necessity for omitting the epididymal fat pad from “gonad” weight measurements since there appeared to be no relationship between its weight and the weight of either the testis or epididymis. Furthermore, the inclusion of epididymal fat resulted in large variation in total unit weight. An interdependent relationship was shown for testis and epididymis weights, indicating it may be appropriate to report a combined value for these entities, though this decision should be based on the intent of the study. A significant saving in time was effected by obtaining the weight of the testis alone. In studies which require male gonad weight assessment, therefore, the testis, excluding epididymis and epididymal fat, should be weighed to maximize the combined factors of time/cost effectiveness and scientific validity.