Intraluminal versus humoral factors in intestinal cell proliferation.

Abstract

Abstract Since both intraluminal and humoral factors have been implicated in postresectional intestinal hyperplasia, we investigated the relative importance of these factors by using cutaneous parabiotic rats with shared gut. Paired cutaneous parabiosis with a common peritoneal cavity was established in inbred Fischer rats. One month later, in one group of animals one member of the pair had a 64 per cent small bowel resection, while in the control group transection alone was performed. Immediately all the rats underwent intestinal crossover, achieved by anastomosing the proximal small bowel of each rat to the distal small bowel of its partner. In the jejunum 2 weeks later there was an 18 per cent increase in DNA content and a 26 per cent increase in wet weight in the animals with resection compared with their parabionts (P < 0·05). There was no difference between the parabionts without resection and the control animals. Because of the intestinal crossover, the more proximally placed ileum from the rats without resection showed a 53–58 per cent increase in DNA content, 28–29 per cent increase in RNA content and 51–57 per cent increase in wet weight compared with the normally placed ileum from the partners that had resection and with the control (P < 0·001). There was no difference between the control and the normally placed ileum from the animals that had resection. The position of the ileum after resection appeared to be the major influence on hyperplasia, since no measurable difference in nucleic acid contents was detected between the ileum of the animals with resection and the control. However, humoral factors do operate locally and may play a permissive role because the jejunum of the animals with resection showed DNA increase when compared with the control.