Gelatinolytic and Caseinolytic Proteinase Activities in the Secretions of the Ventral, Lateral, and Dorsal Lobes of the Rat Prostate1

Abstract

The ventral, lateral, and dorsal lobes of the rat prostate produce secretions rich in protein. We examined these secretions for proteinase activities, using gelatin- and casein-containing SDS-polyacrylamide gel zymographies. The ventral lobe demonstrated both higher activities and more molecular forms of proteinase activities that cleaved these two protein substrates than did the other lobes. Ca(2+)-stimulated gelatinolytic activities of approximately 48, 51, 58, 64, 74, and 80 kDa were found in ventral prostate secretions in addition to activities detected in the absence of added Ca2+: a very strong 27-kDa activity; prominent 22-, 86-, 90-, and 94-kDa activities; and less active 36-, 41-, 100-, 130-, and 140-kDa activities. Ca(2+)-stimulated gelatinolytic activities of 51, 58, 74, 80, 86, 90, and 94 kDa were present in lateral prostate secretions (none were detected in secretions of the dorsal lobe), and Ca(2+)-independent activities of 25, 27, and 100 kDa were found in secretions of both the lateral and dorsal lobes. The Ca(2+)-stimulated activities were inhibited by EGTA and EDTA. Benzamidine inhibited all gelatinolytic activities except for the 22-, 25-, and 27-kDa Ca(2+)-independent forms when Ca2+ was not added to the reaction buffer. However, in the presence of 5 mM CaCl2, the Ca(2+)-stimulated forms of proteinase were unaffected by benzamidine, whereas the other activities sensitive to benzamidine were inhibited. Prominent Ca(2+)-independent caseinolytic activities of 20, 23, 31, 37, 83, 89, and 94 kDa were detected in ventral lobe secretions along with less active forms of about 39, 48, 53, 57, 60, 63, 80, 103, 110, 125, and 160 kDa. Caseinolytic activities of approximately 23, 31, 53, 89, 94, 103, 120, and 125 kDa were found in lateral prostate secretions, and 89, 94, and 103 kDa activities were found in secretions of the dorsal lobe. Quantitatively, most gelatinolytic and caseinolytic activities were present in the soluble portion of the secretion of each prostatic lobe. The ventral, lateral, and dorsal prostate lobes all secrete gelatinolytic and caseinolytic proteinase activities; however, quantitatively the ventral lobe is the most notable in this function since its secretions contain more molecular forms and greater activities of these proteinases.

Matrix metalloproteinase (MMP)‐2 and MMP‐9 activity and localization during ventral prostate atrophy and regrowth

“…Matrix metalloproteinases are also found in seminal plasma, where this enzyme plays an important role in keeping the ducts open and in semen liquefaction (Mann & Lutwak‐Mann, 1982). Their presence in prostate secretion was demonstrated by Wilson et al. (1993a,b) and has recently been reinforced by other authors who also found TIMP‐1 and TIMP‐2 in seminal plasma (McCauley et al.…”

Ultrastructural and biochemical observations on the early changes in apoptotic epithelial cells of the rat prostate induced by castration

“…The supernatants were collected, determined for protein concentrations by bicinchoninic acid assay using bovine serum albumin (BSA) as standard, and stored at -80°C until subsequent analysis. The cytosolic extracts were separated by electrophoresis in duplicate in 10% SDS-PAGE containing 0.1% gelatin under non-reducing conditions (Heussen and Dowdle 1980;Wilson et al 1988Wilson et al , 1993. About 20 µg unreduced and unboiled proteins dissolved in sample dye (1% phenol red, 2.5% SDS, 1% sucrose and 0.5% glycerin) were added to each lane.…”

Effect of Sesame-Supplemented Diet on Prostate and Seminal Vesicle Histology of Adult Rat

“…The rat prostate has been used extensively as a model system to study androgen regulation of growth and function in this gland (Wilson et al, 1993).…”