Urinary testosterone levels in the male blind mole rat (Spalax ehrenbergi)affect female preference

This study investigated the sexual attraction of female blind mole rats to four groups of male mole rats: (a) intact males raised in captivity; (b) in tact males, trapped in the field; (c) captive males injected with testoster one; (d) captive castrated males. In the first part we measured blood testo sterone, androstenedione, and dihydrotestosterone (DHT) levels, by radioimm unoassay; and urine testosterone levels, measured by GC-MS. The second part examined the relationship between urine testosterone levels in males and t heir attractiveness to females. Higher blood and urine testosterone levels were found in the field animals and in those injected with testosterone com pared to captive intact or castrated animals: urine testosterone levels in the two other groups were not detectable. Blood androstenedione levels were also higher in the field animals and in those injected with testosterone c ompared to captive intact or castrated mole rats. Blood dihydrotestosterone levels were not detectable in all four experimental groups. Female mole ra ts chose to spend a longer period of time next to males with high blood and urine testosterone levels and high blood androstenedione levels than next to those with lower levels of these hormones. Because courtship and sexual behavior are influenced both by high levels of blood and urine testosterone and high levels of blood androstenedione, we suggest that the low levels o f courtship and other sexual behavior in captive mole rats may be related t o the lack of female attraction to these males, which display low levels of all three parameters. (C) 2000 Elsevier Science Inc. All rights reserved.