Administration of Additional Phosphorylated Prolactin During Pregnancy Inhibits Mammary Ductal Branching and Promotes Premare Lobuloalveolus Development

摘要

Prolactin (PRL) is a hormone recognized as promoting both proliferation and differentiation in the mammary gland. Current theory proposes that it is the coexisting steroidal environment that dictates which of these two activities predominates. During the tenure of this grant, however, we have determined that the ratio of unmodified PRL (U-PRL) to phosphorylated PRL (as judged by the use of a molecular mimic, S179D PRL) is also important in this regard. Working directly on the mammary gland, U-PRL promotes proliferation, whereas S179D PRL inhibits proliferation and yet promotes differentiation.