Sialic acid binding protein of human endometrium: Its regulation by steroids

In the present study, we have observed that sialic acid binding protein (SA BP - a 54 kDa glycoprotein which was isolated from human endometrial scrapi ngs taken at various stages of the menstrual cycle from normal cycling fema les and purified to apparent homogeneity and was earlier reported from this laboratory) was found in sufficiently detectable amount in the endometrium of normal cycling women whereas it was found in lesser amount in tissue fr om women who have recently entered the post-menopause stage. SABP was obser ved in both follicular and luteal phase of menstrual cycle which was found by western blot analysis. In the de-novo synthesis experiment, synthesis an d secretion of SABP was found to be stimulated by estradiol (E-2) whereas p rogesterone (P-4) was found to have no significant stimulatory effect on it which was also confirmed by HEC cell culture. In the HEC cell culture, pri ming of cells with E-2 was found to influence the effect of P-4 on SABP whe n it was added 2 h after E-2 administration. This was observed by doing imm unoprecipitation followed by SDS-PAGE and autoradiography. Hence this repor t clearly indicates that E-2 regulates the synthesis and secretion of 54 kD a SABP from human endometrium. How E-2 priming of endometrium influences th e effect of P-4 on SABP has been discussed.