Immunohistochemical demonstration of epidermal growth factor in lactating mammary glands of sialoadenectomized mice.

Abstract

Epidermal growth factor (EGF) was demonstrated immunohistochemically in the mammary glands of adult female SHN mice. Immunolocalization was found in all alveolar cells and some luminal contents of the lactating mammary glands, and it became intense during the lactation period. Weak staining was detected in the mammary gland in late pregnancy or in the hypersecretory mammary gland induced by pituitary isograft to the mammary fat pad. EGF staining was found in both intact and sialoadenectomized (sx) mice, and it was more intense in the intact mice than the sx ones, the offsprings mortality of the latter being greater in the first week of lactation. Still, staining in the sx group achieved an intensity comparable to that of the intact group in late lactation. At 7 days after parturition, staining in alveolar cells did not increase in the mother, from which all pups were withdrawn at Day 1 of lactation, though staining was intense in congesting milk. Therefore, the mammary gland itself may produce EGF by a secretory function, especially in lactation stage.