Secretory origin and temporal appearance of the porcine beta-microseminoprotein (sperm motility inhibitor) in the boar reproductive system

A specific antiserum against the porcine sperm motility inhibitor (SMI) was used in Western blotting analysis of tissue homogenates to reveal the poss ible origin of SMI in the boar reproductive system at different ages. The a ges of the boar used were day 0, day 15, day 30, day 60, day 100, day 120, day 135, day 150, and day 210. The tissue homogenates of the day 60 and old er showed immunoreaction. The results were further checked by indirect immu nohistochemical staining and observed under light microscope. The SMI antig en appeared in the epithelial cells and in the lumen of the secretory ducts of the prostate gland. These results indicate that porcine SMI is synthesi zed only by the postnatal prostate gland. The homogenate of the prostate gl and of day 100 was also used for the purification of SMI. The prostatic SMI was co-eluted with the seminal SMI in the reversed phase HPLC. Mass spectr ometric analysis of the prostatic SMI revealed a molecular weight of 10,066 . These results indicate that the prostatic SMI is identical to that purifi ed from seminal plasma (C) 2001 Wiley-Liss, Inc.