AMOUNT AND DISTRIBUTION OF COLLAGEN IN PANCREATIC TISSUE OF DIFFERENTSPECIES IN THE PERSPECTIVE OF ISLET ISOLATION PROCEDURES

Because collagen is the major target in the enzymatic dissociation of the pancreas for islet isolation, we determined the amount of collagen and its distribution in a comparative study comprising normal pancrea ta of rat, dog, man, young pig, and adult pig. Collagen content was de termined using a colorimetric method and its distribution was assessed in tissue sections stained with Sirius red. The collagen content is r elatively low in the rat and adult pig pancreas, and the amount of col lagen is relatively low in the septa of the rat and dog pancreas. Not the amount of collagen in the septa but collagen in the rest of the pa ncreas, mainly located between the acini, seems to determine the disso ciation of the pancreatic tissue. This can be exemplified by the highe r islet yields obtained from the adult vs. the young pig pancreas; the latter contains a higher total amount of collagen but a similar, rela tively high, amount of collagen in the septa. A high amount of collage n surrounding the islets seems to be of secondary importance in islet isolations, because yields of the same magnitude are obtained from the canine and human pancreas containing a relatively low vs. high amount of collagen around the islets but a similar total collagen content. T he rat pancreas contains both a low total amount of collagen and a hig h amount of collagen around the islets; therefore, the general experie nce that islet isolation procedures are effective in rats can be readi ly understood.