The effect of oestrogen on selective transfer of IgG1 into mammary secretion of ewes.

Two separate experiments were conducted to examine the effects of exogenous oestrogen on selectivetransfer of IgG1 into mammary secretion of ewes. In one experiment, non-pregnant ewes were induced to lactate artificially by first developing mammary glands with injections of progesterone plus low doses of oestrogen then triggering milk secretion with either glucocorticoid or high doses of oestrogen. In the other experiment, lactating ewes were injected with oestrogen each day for 6 days. The results of the experiments suggest that oestrogen affects selective transfer of IgG1 into mammary secretion of the ewes. Moreover, the results show that, in the absence of high levels of oestrogen in blood, the magnitude of the selective transfer of IgG1 into mammary secretion is related inversely to the synthetic activity of the glandular epithelium.