Potentiation of Cd-induced pulmonary injury in alpha 1-antitrypsin suppressed rats

The effect of intravenous cadmium on exocrine and endocrine pancreatic functions in conscious dogs

This study was conducted in conscious dogs to investigate the effect of cadmium on exocrine pancreatic secretion and plasma levels of pancreatic polypeptide (PP). Mongrel dogs weighing 20-25 kg were prepared with chronic gastric and pancreatic fistulas, and were acclimated for 3 wk prior to studies. The dogs were given iv infusion of saline, secretin at 25 U/kg/h, cadmium at 0.15 mg/kg/h, or various combinations of these compounds. During the infusion, pancreatic juice and blood samples were collected at regular intervals. Secretin infusion stimulated pancreatic secretions. Infusion of cadmium alone had no effect on pancreatic secretions and plasma levels of PP. When cadmium infusion was stopped with the background infusion of secretin, pancreatic secretions and plasma levels of PP were significantly increased. This latent effect of cadmium on pancreatic secretions and plasma levels of PP was abolished by an iv injection of 100 mg/kg atropine. These results indicate that cholinergic signaling may be involved in the effect of cadmium on pancreatic exocrine secretions and PP release. The current study suggests that cadmium may have diverse physiological functions in both exocrine and endocrine pancreatic cells.

A comparative study of the effects of inhaled cadmium chloride and cadmium oxide: pulmonary response

The effects of aerosols of cadmium chloride (CdCl2) and cadmium oxide (CdO) on pulmonary biochemical function were compared. Rats and rabbits were exposed to 0.25, 0.45, or 4.5 mg Cd/m3 for 2 h. Pulmonary toxicity was determined histologically and biochemically. Cadmium chloride and CdO showed a deposition response that was linearly related to the chamber concentration. Both compounds caused multifocal, interstitial pneumonitis 72 h after exposure, but the CdO lesion was more severe with proliferation of fibrocytic-like cells as well as pneumocytes. Comparing the two Cd compounds at the highest concentration (4.5 mg Cd/m3), the biochemical responses in the rat were similar. The majority of the effects occurred 72 h after exposure, with significant increases in lung weight, lung-to-body weight ratio, GSH reductase, GSH transferase, and G-6-PDH. However, GSH peroxidase was inhibited immediately after the CdO exposure. Cadmium oxide-related alterations in the parameters studied could easily be distinguished from those of CdCl2 at the exposure concentration of 0.45 mg Cd/m3. The response pattern in the rabbit resembled that of the rat. In both species Cd had a consistent inhibitory effect on pulmonary GSH peroxidase, even at the lowest concentration of 0.25 mg Cd/m3. Based on these findings, inhaled CdO appeared to be more toxic to the lung than inhaled CdCl2.

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

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.