Elastolytic Enzymes and Elastin in the Aging Rat

Abstract

Since improved methods make it possible to determine both elastoproteinase and elastomucase activity in crude pancreatic extracts, the effect of age on enzyme titer in the pancreas was studied in virgin Wistar rats of both sexes. In males, the elastoproteinase concentration (in elastoproteinase unit [EU] per gram acetone-dried pancreas) decreased with age over the whole period of 0–24 months; the elastomucase Em-I and Em-S concentrations (in elastomucase unit [Em-U] per gram acetone-dried pancreas) rapidly decreased with age up to 12 months (Em-S) and 18 months (Em-I), remaining nearly constant after that age period. In female rats, the elastoproteinase concentration remained constant during the 1st year of life, increased rapidly between 15 and 18 months, then decreasing to the 15-month level at an age of 27 months. The titer of both elastomucases fell during the growth of the females, remaining constant between 6 and 15 months of age and showed a rapid increase in enzyme level between 15 and 18 months. Although there was a tendency for the enzyme concentration to decrease after 18 months, the fall was not statistically significant. The data obtained with rat pancreas were compared with those for human pancreatic enzymes and for human serum ‘elastoproteinase’ reported previously. Similar age-relationships were found.