Effects of Testosterone and 7α-Methyl-19-Nortestosterone (MENT) on Sexual and Aggressive Behaviors in Two Inbred Strains of Male Mice (original) (raw)

1996, Hormones and Behavior

whereas aggressive behaviors of the MENT-treated gen, 7a-methyl-19-nortestosterone (MENT), which is not groups were not different from those of the castrated 5a-reduced to dihydrotestosterone, were compared to control groups. These results suggest that MENT can those of testosterone in two inbred strains of male restore both male sexual behaviors and reproductive ormice, C57BL/6J and DBA/2J, in two experiments. In the gan weights as effectively as testosterone, at one-third first experiment, seminal vesicle (SV) weights, kidney of the testosterone dose, without stimulating male agweights, and circulating steroid levels were examined in gressive behaviors. ᭧ 1996 Academic Press, Inc. castrated mice treated with three doses of testosterone (3.125, 12.5, or 50 mg/day) or four doses of MENT (1, 4, 16, or 64 mg/day) for 2 weeks to determine the optimal replacement levels of the two androgens for behavioral 7a-Methyl-19-nortestosterone (MENT) is a synthetic studies. Both testosterone and MENT dose-dependently androgen that is not 5a-reduced to dihydrotestosterone increased the SV weights that were greatly reduced, in (Agarwal and Monder, 1988; Sundaram, Kumar, and both strains, by castration. MENT was more effective . The use of MENT in a combination with than testosterone in increasing SV weights, fully restormale contraceptive drugs appears to be more effective ing them to intact levels in both strains, at the dose of than testosterone . In castrated 4 mg/day. At the dose of 12.5 mg/day, testosterone rerats, the relative potency of MENT vs testosterone is stored the SV weights completely in C57BL/6J and up to much greater in restoring bulbocavernosus plus levator 80% in DBA/2J mice. DBA/2J mice were more sensitive ani muscle weights and suppressing postcastration inthan C57BL/6J mice to both androgens, as measured crease in serum gonadotropin levels than in restoring by kidney weights, although circulating levels of either steroid were very similar between the two strains of seminal vesicles or prostate gland weights (Kumar, Dimice. In the second experiment, we investigated the efdolkar, Monder, Bardin, and Sundaram, 1992). MENT, fects of testosterone (12.5 mg/day) and MENT (4 mg/day) therefore, is expected to support male sexual behaviors on sexual and aggressive behaviors. In each strain, without overstimulating prostate growth, where the ef-MENT-treated and testosterone-treated mice showed fects of testosterone can be undesirably amplified by similar numbers of mounts or intromissions. MENT was its conversion to dihydrotestosterone. A recent study equally effective as testosterone to fully (C57BL/6J) or in male rats has indeed shown that 10 mg/day of MENT partially (DBA/2J) restore sexual behaviors as well as the fully restored sexual behavior (percent of animals with SV weights to the intact levels. In contrast, MENTmounts and intromissions) in castrated male rats foltreated mice of both strains were much less aggressive lowing 1 week treatment although recovery of ejaculathan testosterone-treated mice. In both C57BL/6J and tions took a longer time (Morali, Lemus, Munguia, Ar-DBA/2J mice, testosterone fully restored aggression to the intact levels as measured by aggression latency, teaga, Perez-Palacios, Sundaram, Kumar, and Bardin, 1993). This dose of MENT is 1/20 of the effective dose of testosterone. The effects of MENT on other types of