[Comparison of the mechanism of action of insulin and prolactin].

One of the major actions of prolactin in the mammary cell is to activate the expression of casein genes by enhancing the transcription rate of the genes. Anti-prolactin receptor antibodies can mimic prolactin action when added to mammary cells, suggesting that a relay is formed at the membrane level and transferred to the target genes. None of the classical hormone intracellular relays can account for the transfer of the prolactin message.