Experimental and clinical study on the efficacy of colchicine in rheumatoid arthritis

The effect of colchicine on arthritis induced by Freund's complete adjuvant in rats was studied. 50 micro g/kg colchicine orally administered twice daily for 14 days starting from 2 days before the injection of the mycobacterium adjuvant was found to cause a significant retardation of development of arthritis in rats. 75 micro g/kg colchicine orally administered for 12 days to rats with established arthritis caused a significant decrease of the dorsoplanter thickness of the rat paw. On the other hand, oral administration of colchicine 25 micro g/kg daily to rheumatoid patients in actual remission caused some protection against deterioration as indicated by the persistance of the remmissive parameters. This means that further studies using higher concentrations of colchicine are warranted

Effect of allopurinol on tolbutamide pharmacokinatics and hypoglycaemic activity in rabbits

The effect of allopurinol on pharmacokinetic parameters and hypoglycemic activity of tolbutamide was assessed in fasted rabbits. Pretreatment of animals with allopurinol [30 mg/kg orally] 2 hours before tolbutamide injection [50 mg/kg i.v.] resulted in a significant increase in plasma tolbutamide levels compared to those of rabbits received tolbutamide alone. The plasma half life [t1/2] of tolbutamide increased from 6.60 to 12.83 hours by allopurinol pretreatment. The hypoglycemic activity of tolbutamide was also significantly enhanced in rabbits received allopurinol. These results suggested the importance of tolbutamide dosage adjustment when allopurinol is given concurrently

Effects of selective alpha 2-adrenoreceptors agonists on certain aspects of glucose metabolism in rabbits

In conscious fasted rabbits, the effects of two selective alpha-2 adrenoreceptor agonists, clonidine and guanfacine, on basal serum glucose, glucose tolerance and insulin secretion were investigated. Both drugs inhibited insulin secretion and resulted in hyperglycemia and impaired glucose tolerance. Clonidine induced more impairment of glucose tolerance compared to guanfacine. These results indicated that adrenergic inhibition of insulin secretion is mediated by alpha-2 adrenoreceptors on pancreatic B-cells