Secretion of insulin by the nonruminant herbivore (pony) pancreas perfused in vitro.

A technique is described to rapidly remove the pancreas from fed, adult Shetland ponies and to perfuse it in vitro. Thirty minute squarewave glucose stimuli (300 or 800 mg/dl) resulted in a dose dependent pattern of insulin secretion. The initial spike was similar to that observed in other mammals. Subsequent secretion, however, gradually decreased in relation to the initial spike. Butyrate (253 /~M/liter) st imulated insulin secretion in the absence of glucose, whereas acetate (19.2 raM/liter) or propionate (505 ~M/liter) failed to stimulate insulin secretion. The pony (a nonruminant herbivore) derives much of its energy from VFAs produced by microbial fermentat ion in the cecum and large colon. They have a digestive system with factors common to both ruminant and monogastric species. The perfused pony pancreas demonstrates insulin control mechanisms with aspects similar to both of these groups. (