Mean (± SEM) mRNA expression for PrlrL in rat mammary tissue as a function of reproductive state and experience. N-Di, nulliparous, diestrous group; P-D3, primiparous, Day 3 lactating group; P-D10, primiparous, Day 10 lactating group; P-Di, primiparous, nonlactating, diestrous group; M-D3, multiparous, Day 3 lactating group; M-D10, multiparous, Day 10 lactating group. *Denotes significant difference versus the N-Di group (P < 0.05). **Denotes significant difference versus the P-Di group (P = 0.01); n = 5–8/group.