Effect of estradiol and progesterone on udder growth in goats in vivo and lipid synthesis in goat mammary tissue in vitro.

The effect of estradiol-17beta (E) and progesterone (P) and E, P and deprenon (D; an inhibitor of prolactin secretion) treatment on udder growth, colostrum-like formation and on the induction of lipid synthesis in mammary organ culture were studied. Administration of E and P for 8-14 days induced udder growth and colostrum formation. Intensive mammary growth and udder distention with secretion occurred following hormone treatment. Simultaneous administration of D prevented both udder growth and colostrum formation. In mammary explants from E, P and D treated goats the rate of incorporation 14C-acetate into lipids was increased by insulin (I), cortisol (F) and prolactin (M) as compared with the effect of I or I plus F. The tissue from placebo treated goats and goats treated with E and P responded to M either slightly or not at all. The high sensitivity of mammary tissue from goats treated with E, P and D to M was demonstrated immediately following the administration of E and P for 8 days and also 10 days after the treatment, but not 23 days following hormone administration.