UTEROCALIN - A MOUSE ACUTE-PHASE PROTEIN EXPRESSED IN THE UTERUS AROUND BIRTH

Mouse SIP24/24p3 is a 24 kDa lipocalin expressed in the liver and secr eted into the bloodstream during the acute phase response (APR). In th is report we show that SIP24/24p3 mRNA and protein are expressed in th e uterus around parturition at levels higher than are found in the liv er during the APR. Because of the unique expression of this lipocalin in the uterus, we have named this protein uterocalin. Contrary to its expression pattern during the APR, there is little or no expression of uterocalin in the liver during or after pregnancy. Also, unlike the A PR, and despite its high level of expression in the uterus, uterocalin was not detected in the blood or amniotic fluid. Day 19 and postpartu m uterine samples were examined by immuno-cytochemistry. Uterocalin wa s found in the luminal epithelium at day 19 and in the glandular epith elium in postpartum samples. Although some uterocalin remained in the luminal epithelium, most of the uterocalin was found deposited on its luminal surface. The uterus undergoes extensive tissue remodeling duri ng pregnancy and suffers stress and tissue damage around parturition. Uterocalin could be part of the local inflammatory response associated with parturition. (C) 1997 Wiley-Liss, inc.