Pancreatic growth after distal small bowel resection is altered with aging

We have examined age-related changes in the stimulatory effects of distal small bowel resection on the growth of the pancreas and on polyamine biosynthesis. Two groups of male Fischer 344 rats (young; 4-month-old, aged; 25-month-old) underwent either 70% distal small bowel resection or transection of distal small bowel (control). Rats from each treatment group of each age were sacrificed on the 10th or 20th postoperative day (POD), and pancreas was weighed and assayed for DNA, RNA, and protein contents as well as polyamines. We found that young rats with distal small bowel resection exhibited significant increases in pancreatic weight, RNA, protein, putrescine, and spermine contents on the 10th POD, but aged rats that had undergone resection showed only increased spermine content. On the 20th POD distal small bowel resection increased pancreatic weight, DNA, RNA, and protein as well as spermidine and spermine contents in young rats; aged rats increased pancreatic weight only. These findings suggest that the trophic responses of the pancreas to distal small bowel resection are altered in aged rats, and that the polyamine metabolism might be associated with this impaired response.