[Effect of montmorillonite on diffussion of urea between blood and intestine and on absorption of intestine in rats].

OBJECTIVE: To study the effect of montmorillonite on promoting diffussion of urea from blood vessel to intestine and preventing absorption of urea in intestine. METHODS: Rat intestine tract and blood vessel were perfusated circularly with intestinal tract perfusate and blood vessel perfusate with or without urea 1 g/L, respectively. The concentration of urea in perfusates was measured by urease and glutamic dehydrogenase coupling method. RESULTS: The blood vessel was circularly perfusated with vascular perfusate containing urea and intestinal tract was circularly perfusated with intestinal perfusate without urea. The concentration of urea in vascular perfusate decreased gradually, and the concentration of urea in intestine perfusate increased slowly. When montmorillonite was added into the intestinal tract, the urea concentration in both intestinal tract perfusate and the vascular perfusate in montmorillonite 0.5 g/kg and 1.0 g/kg groups were significantly lower than that of control group (P < 0.05). The blood vessel was circularly perfusated with vascular perfusate without urea and intestinal tract was circularly perfusated with perfusate containing urea, the concentration of urea in intestine perfusate decreased little by little, and the concentration of urea in vascular perfusate increased slowly. After montmorillonite was administrated into the intestinal tract, the urea concentrations in both the vascular perfusate and intestinal tract perfusate in montmorillonite 0.5 g/kg and 1.0 g/kg were obviously lower than that of control group (P < 0.05). CONCLUSION: Montmorillonite promotes the diffusion of urea from blood vessel to intestine, and inhibits the absorption of urea in intestine.

Montmorillonite ameliorates hyperthyroidism of rats and mice attributed to its adsorptive effect.

The present study aims to evaluate the adsorbing effect of montmorillonite on thyroid hormone in the entero-hepatic circulation. The concentration of thyroid hormone in the serum of hyperthyroidism model rats and in solution was measured by radioimmunoassay and ultraviolet spectrometry, respectively. The body weight, temperature, and consumption of food and water were observed in hyperthyroidism model rats. Furthermore, hypoxia tolerance, sodium-pentobarbital-induced sleep time, spontaneous activities were measured on hyperthyroidism model mice after being treated with montmorillonite. Results showed that montmorillonite adsorbed thyroxin (T(4)) and triiodothyronine (T(3)) in vitro. Montmorillonite at dosage of 1.0 g/kg and 0.3 g/kg decreased thyroid hormone levels on hyperthyroidism model rats; Montmorillonite (2.0 g/kg and 0.6 g/kg) prolonged the sleep time, improved the hypoxia tolerant capacity and reduced the spontaneous activities of the hyperthyroidism model mice. These results suggest montmorillonite has anti-hyperthyroidism effect attributed to its adsorptive effect.