The role of nitric oxide in the biological activity of prolactin in the mouse mammary gland.
In mouse mammary epithelial cells, prolactin transiently elevates nitric oxide (NO) to a maximum of 6 nmol/mg protein at 15 min, after which levels fall rapidly. This stimulation can be achieved by as little as 100 ng prolactin/ml and can be mimicked by 100 microg sodium nitroprusside/ml. NO is both necessary and sufficient to mediate the prolactin-induced redistribution of its receptor from internal pools to the cell surface. NO can also enhance DNA synthesis stimulated by submaximal prolactin concentrations (50 ng/ml), but it is not necessary at pharmacological prolactin concentrations (1 microg/ml). In contrast, NO completely inhibits alpha-lactalbumin production. In summary, prolactin transiently elevates NO to enhance DNA synthesis and suppress premature differentiation; thereafter, NO declines, DNA synthesis ceases and differentiation proceeds. This data suggest that NO may mediate some of the effects of prolactin on growth in the mammary gland.
Bolander
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Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA. bolander@sc.edu
D000818:Animals; D001693:Biological Transport, Active; D001940:Breast / Q000166:cytology / Q000378:metabolism*; D004261:DNA Replication / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004848:Epithelium / Q000378:metabolism; D005260:Female; D007700:Kinetics; D051379:Mice; D008809:Mice, Inbred C3H; D009569:Nitric Oxide / Q000378:metabolism / Q000502:physiology*; D011388:Prolactin / Q000494:pharmacology*; D011981:Receptors, Prolactin / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D015290:Second Messenger Systems; D015854:Up-Regulation
D011981:Receptors, Prolactin; D009569:Nitric Oxide; D011388:Prolactin