Anabolic and androgenic activities, in rat, of some nandrolone and androstanolone esters.

The anabolic and androgenic activities of the formate to undecanoate esters of nandrolone and formate to valerate esters of androstanolone, after intramuscular injection, have been determined in rat. The response to a given dose was measured as cumulative weight (the area under the plot of weight of indicator organ against time). Levator anus muscle was used to assess anabolic activity, and the sum of the cumulative weight for prostate and seminal vesicles for androgenic activity. Log dose-log cumulative weights plots were parallel, and biological activities were expressed as the cumulative weight corresponding to a 2 muM dose, calculated from the regression lines. Anabolic-androgenic ratios for both series were calculated and were found to be minimum in the region of the propionate and butyrate. The anabolic-androgenic ratios of the nandrolone esters continued to increase after the minimum, as the series ascended. This method is believed to give a reliable assessment of anabolic and androgenic activities of steroid esters.