Perinatal Influences On The Reproductive Behavior Of Adult Rodents

Abstract In litter-bearing rodent species, the location that a male or female fetus occupies relative to siblings of same or opposite sex influences its level of prenatal exposure to gonadal hormones. In particular, varying amounts of prenatal exposure to testosterone produce cascades of neurendocrine events that, in turn, result in variation in such biologically important characteristics as the timing of puberty, an individual’s lifetime fecundity, the sex ratio of its offspring, and the magnitude of its parental investment. Consequently, studies of intrauterine effects on adult patterns of reproduction provide a means of examining the relationship between normally occurring variation in perinatal exposure to hormones and the variation in reproductive tactics often seen in mammalian populations. Dams can only indirectly influence the intrauterine position of their offspring by varying the size and sex ratio of their litters and the distribution of litter members within the uterus. However, because the same hormonal mechanisms that support indirect maternal effects on behavior also support direct maternal influences on the phenotype of offspring, examination of effects of intrauterine position increases understanding of direct maternal effects on phenotypes of adult mammals.

Perinatal Influences On The Reproductive Behavior Of Adult Rodents Conferences