Abstract:
Cathepsin L has been proposed to be involved with theendothelial-chorial type of placentation in the cat. Little informationconcerning the presence and secretion of cathepsin L is available for aspecies with noninvasive epitheliochorial placentation such as the pig.Cathepsin L activity in uterine flushings and endometrium from gilts duringdifferent days of the oestrous cycle and early pregnancy was analysed throughspecific substrate metabolism and Western blot analyses with antiserum againstcat endometrial cathepsin L. This antiserum was utilized to determine thecellular localization of the enzyme within porcine endometrium. Cathepsin Lactivity within uterine flushings was elevated on Day 15 of the oestrous cycleand early pregnancy, with activity declining on Day 18. Cat cathepsin Lantiserum cross-reacted with a group of 46, 40 and 38 kDa uterine proteins anddetected a product within the surface and glandular epithelium of theendometrium. The appearance of the 40 kDa protein was first detected on Day 10of the oestrous cycle with the 38 kDa proteins appearing on Day 15 and 18 ofpregnancy. The 40 and 38 kDa uterine proteins appear to be steroid regulatedas 12 days of progesterone administration is necessary to detect the proteinsand cathepsin L activity.