Sexually dimorphic placental development throughout gestation in the spiny mouse ( Acomys cahirinus )

Abstract Objectives It has been hypothesized that male fetuses down regulate placental growth during periods of accelerated fetal growth. We aimed to investigate this, and determine whether sexual dimorphism was apparent in the spiny mouse placenta. We hypothesized that expression of fetal growth promoters would be higher in placentas of males, whereas genes involved in placental structural development would be more highly expressed in placentas of females. Methods Spiny mouse dams, a precocial rodent with an in utero endocrine milieu dissimilar from other rodents, but akin to humans, were sacrificed at gestational ages 15–37 (term = 39 days). Placentas were collected and processed for histology or qPCR analysis of selected genes ( GCM1 , MAP2K1 , SLC2A1 , NR3C1 , IGF1 , IGF1R ). Results Fetal and placental weights were similar for both sexes. Placentas of female fetuses had less spongy zone ( PSEX