Human growth hormone but not ovine or bovine growth hormones exhibits galactopoietic prolactin-like activity in organ culture from bovine lactating mammary gland.
Explants from the mammary gland of 6 lactating cows were cultured in M-199 medium containing insulin (1.0 micrograms/ml) and hydrocortisone (0.5 micrograms/ml) and supplemented with bPRL (0.2-1.0 micrograms/ml) or oGH (0.1, 0.5 and 2.5 micrograms/ml) or bGH or hGH (0.2 and 1.0 micrograms/ml). It was found that neither oGH nor bGH significantly increased (P less than 0.05) the casein and fat synthesis and alpha-lactalbumin secretion above the control level. A significant and almost equal increase was, however, observed in the presence of bPRL and hGH, but was not influenced by the simultaneous addition of oGH to bPRL-containing medium (both at 0.5 micrograms/ml). Various hormonal treatments did not affect casein secretion and glucose uptake. High correlations (r = 0.89-0.97) were found between the mean values for casein and fat synthesis and alpha-lactalbumin secretion. Our results suggest that (a) the in vivo galactopoietic activity of bGH does not result from a direct effect of synthetic capacities on the mammary gland, and (b) hGH is a potent lactogen in the organ culture of bovine lactating mammary tissue.
D000818:Animals; D002364:Caseins / Q000378:metabolism; D002417:Cattle; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology*; D006801:Humans; D007768:Lactalbumin / Q000378:metabolism; D007774:Lactation; D008055:Lipids / Q000096:biosynthesis; D008321:Mammary Glands, Animal / Q000187:drug effects*; D009924:Organ Culture Techniques; D011247:Pregnancy; D011388:Prolactin / Q000494:pharmacology; D012756:Sheep; D013045:Species Specificity
D002364:Caseins; D008055:Lipids; D011388:Prolactin; D013006:Growth Hormone; D007768:Lactalbumin