Changes in the activity of lactose synthetase in the goat udder during pregnancy

The lactose synthetase activity of homogenates and particulate fractions prepared from the udders of goats killed at various stages of pregnancy were determined. Both components of the enzyme, galactosyltransferase and alpha-lactalbumin, became detectable about half way through the gestation period, at the time when rapid proliferation of mammary epithelial tissue commences. Throughout the second half of pregnancy the udder possessed a high level of lactose synthetase activity though the lactose content of the tissue did not increase. These findings are discussed in relation to the endocrine control of lactogenesis in the goat and possible mechanisms for the induction of milk production at parturition.