L-homoarginine suppresses exocrine pancreas in rats

Previously, we found that guanidinated casein, a L-homoarginine-containing protein, was a more potent stimulator of pancreatic enzyme secretion than intact casein in rats. In this study, we examined secretory response and adaptation of the exocrine pancreas to the administration of free L-homoarginine in normal and bile-pancreatic juice (BPJ)-diverted rats. An intraperitoneal injection of L-homoarginine (10 mg/rats) produced immediate and transient reduction in pancreatic secretion in BPJ-diverted rats, but not in normal rats. The BPJ-diverted rats were fed with either a 25% casein, 45% casein, or 45% casein diet supplemented with L-homoarginine (19 g/kg diet) for 4 days. Feeding of a diet containing L-homoarginine inhibited the pancreatic adaptation induced by the high-protein diet. These results indicate that L-homoarginine has an inhibitory effect on the secretion and production of exocrine pancreatic enzyme in BPJ-diverted rats, and L-homoarginine may have an antagonistic effect on CCK receptors.