[Effects of cysteamine on canine splanchnic D-cells]

It has recently been reported that the oral administration of cysteamine causes a depletion of somatostatin content in various tissues of the rat concomitant with duodenal ulcer. Producing somatostatin deficient animals is important for understanding the role of somatostatin in the homeostasis of ingested nutrients. The present experiment was designed to investigate the acute and chronic effects of cysteamine on canine splanchnic D-cells. When 2 g of cysteamine was administered to normal mongrel dogs, it caused a bloody stool. However, somatostatin-like immunoreactivity (SLI) levels in the peripheral vein did not change although the insulin, glucagon and glucose levels increased. In isolated perfused canine pancreases, cysteamine (10 microM-10 mM) showed no specific effect on the somatostatin secretion. The chronic effect of systeamine on the canine D-cells was studied by using dogs to which cysteamine was administered 3 times (2 g, P.O., every 10 days) at least 4 weeks before the experiment (cysteamine dogs). Hormone secretions from the perfused pancreases isolated from the cysteamine dogs were normal. The increases in somatostatin-14 levels in the pancreaticoduodenal vein, short gastric vein and gastroepiploic vein in response to the intragastric administration of 1N HCl were also normal. The SLI contents and the characteristics in molecular size of tissue extracts from the cysteamine dogs were similar to those of normal dogs. Thus, it is concluded that cysteamine has no specific effect on canine splanchnic D-cells.