Transfer of [3H]estradiol-17β and [3H]progesterone from conspecifics to cohabiting female mice

Estradiol-17β (E₂) and progesterone (P₄) play critical roles in female reproductive physiology and behavior. Given the sensitivity of females to exogenous sources of these steroids, we examined the presence of E₂ and P₄ in conspecifics' excretions and the transfer of excreted steroids between conspecifics. We paired individual adult female mice with a stimulus male or female conspecific given daily injections of [³H]E₂ or [³H]P₄. Following 48 …