The influence of cadmium (CdCl2) on the canine plasma levels of gastrin, cholecystokinin (CCK), and pancreatic polypeptide (PP)

Abstract

The influence of cadmium on basal and stimulated plasma levels of gastrin, cholecystokinin (CCK), and pancreatic polypeptide (PP) was investigated in conscious dogs using three doses of cadmium (0.15, 0.5, and 0.75 mg Cd/kg-h). Levels of gastrointestinal (GI) hormones were stimulated with bombesin (BBS), a peptide known to stimulate GI hormone release. Plasma cadmium was measured employing atomic absorption spectrophotometry and GI hormone levels were measured with specific radioimmunoassays (RIA). Basal plasma levels of hormones (pg/mL) in the dogs were in the range (mean ± SE): 38±5 to 44±6 for gastrin, 80±25 to 107±17, for CCK and 120±5 to 142±5 for PP; these levels did not change with cadmium. Significant increases above basal levels in all three hormones were found with infusions of BBS and with BBS plus cadmium. Gastrin levels remained steady during Cd and saline after BBS; however, CCK and PP levels dropped to values that were 68 and 73% less than their stimulated peak levels. With reinfusion of BBS, gastrin, CCK, and PP were significantly elevated above basal; however, the peak values for CCK and PP, but not gastrin, were less than those found during the first BBS infusion. The data suggest that in response to bombesin, cadmium has little or no effect on the release of gastrin, but that is exerts a latent effect on the release of both CCK and PP.