Comparative measurement of the lactogenic activity of ovine placental lactogen in rabbit and ewe mammary gland.
Ovine placental lactogen is known to bind to prolactin receptors and to initiate milk synthesis in the rabbit mammary gland. However, this hormone exhibited a very low capacity of competing with 125I-labeled human growth hormone for the binding to membranes extracted from ewe mammary gland. Ovine placental lactogen was very efficient in provoking the accumulation of beta-casein mRNA in rabbit mammary explants but was much less active on ewe mammary explants. These data indicate that the placental hormone is not a potent lactogen in the homologous species and that its role in the control of mammary gland development and activity may have been previously overestimated.
D000818:Animals; D001667:Binding, Competitive; D002364:Caseins / Q000096:biosynthesis; D005260:Female; D013006:Growth Hormone / Q000378:metabolism; D006801:Humans; D007774:Lactation; D008321:Mammary Glands, Animal / Q000378:metabolism*; D008566:Membranes / Q000378:metabolism; D010928:Placental Lactogen / Q000032:analysis* / Q000378:metabolism / Q000502:physiology; D011247:Pregnancy; D011817:Rabbits; D011956:Receptors, Cell Surface / Q000032:analysis*; D011981:Receptors, Prolactin; D012756:Sheep
D002364:Caseins; D011956:Receptors, Cell Surface; D011981:Receptors, Prolactin; D013006:Growth Hormone; D010928:Placental Lactogen