Regulation of colostrogenesis in cattle

The prepartum transfer of immunoglobulins from maternal circulation into ma mmary secretions, i.e., colostrogenesis, is a distinct stage of mammary gla nd development. Colostrogenesis is clearly regulated in part by lactogenic hormones. Estrogen and progesterone are necessary for initiation of IgG(1) transfer into colostrum. Recent work suggests that down regulation of IgG(1 ) receptor activity constitutes a previously unrecognized phase of differen tiation which is controlled by prolactin. Like most aspects of mammary func tion, there is clear evidence that colostrogenesis is affected by local mec hanisms within the mammary gland as well. To more thoroughly investigate me chanisms controlling colostrogenesis, methods are needed to evaluate the mo lecular regulation of IgG(1) receptor expression. Recently, the bovine gene for this receptor has been cloned and sequenced. Efforts are underway to c onfirm that the cloned gene encodes the authentic mammary IgGl receptor exp ressed in vivo, and to relate published studies in other species to the in vivo identification, function, and hormonal regulation of this putative bov ine receptor. (C) 2001 Elsevier Science B.V. All rights reserved.