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Gross and morphometric studies were undertaken on lO digestive tracts of the agouti (DasyProcta 妙 o 珈 α) ．The most prominent features included a long small intestine which had a mean l，。 gth 。f 700． 16± 124・m and f・ rm ・d 49． 1± 3、 9 ％ 。f th・ t・ t・l w ・ight ・f the enti ・e dig・・tive t・act ・The large intestine had a large sacculated caecum which formed l6， 8± 4 ， ll％ of the total weight of the diges − tive tract． The colon and rectum had a mean length of ll7 ． 0±2 ． 5 cm and formed 18． 788± 2 ． 11 ％ of the total weight of the digestive tract ， Large anal sac glands had openings into the anus ． The histology of the different components of the digestive tract was done on a male agouti and the results suggested that the small intestine has a remarkable proliferation of villi；the epithelium is simple columnar ． Numerous intes − tinal gland 、 w ・・e l・・at ・d t・w ・ ・d・ th・ base・f 出 e epith ・ li ・m ， and th・ gland ・ h・ d num … u・ gl ・bl・辷 ・ell ・・

The plasma concentration profile of the antidiabetic agent tolbutamide was investigated in glycerol-induced acute renal failure (ARF) rats receiving or not receiving peritoneal dialysis (PD) to assess the impact of performing dialysis on tolbutamide pharmacokinetics. It was revealed that the plasma concentration of tolbutamide was decreased by 23.4% by performing PD in ARF rats, while it was not changed by PD in normal rats. The decrease in the plasma concentration of tolbutamide was nearly proportional to the increase in its volume of distribution. To clarify the mechanisms responsible for the decreased tolbutamide concentration caused by PD, the plasma protein binding of tolbutamide was examined in normal and ARF rats. The plasma unbound fraction of tolbutamide was higher in ARF rats than in normal rats, and the dissociation constants were 3.5+/-0.7 and 5.5+/-0.2 microg in normal and ARF rats, respectively. These results indicated that the unbound fraction of tolbutamide was increased in ARF rats because of its protein binding being suppressed. It is therefore likely that since a measurable amount of tolbutamide can distribute in peritoneal dialysate in ARF rats, but not in normal rats, the plasma concentration of tolbutamide was decreased by performing PD only in ARF rats. These findings suggest that diabetes medication with tolbutamide should be carefully performed in patients receiving dialysis treatment.

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