Histological studies on the islets of Langerhans in normal rabbits and rats and those treated with sulfonamide derivatives.

Three normal control and 9 treated male adult rabbits and 10 control and 18 treated male adult rats were used for the experiment. In rabbits, 0.25, 0.5 and 1. 0g of IPTD, 0.5, 1.0 and 2.0g of BZ-55 and 2.0g of D-860 were injected intravenously per kg of body weight as well as 1.0 and 2.0g of D-860 intramuscularly. In rats, 0.25, 0.5 and 1.0g of IPTD, 0.5, 1.0 and 2.0g of BZ-55 and 0.5, 1.0 and 2.0g of D-860 were given intraperitoneally per kg of body weight. The blood sugar value was determined by Somogyi-Nelson's method before and at an hour interval up to 6hrs. after injection in rabbits. The value reached to minimum in 2 to 4hrs. in both rabbits and rats, the decrease being in general proportional with the dosage.In control rabbits alpha cells with clear polygonal contours were scattered either in the periphery or the central area of the islets and stained diffusely with phloxin of Gomori's CHP method. It was observed that alpha cells contain a small amount of Mt in the cell bodies. In rats, it was found the alpha cell zone formed a sort of syncytium on the periphery of the islets surrounding the central area. They were rich nuclei and in rod shaped structures and P-positive. Beta cells having in general clear boundaries were packed with rod shaped structures (CH-positive) and mitochondria or fine granules. Beta granules were not coarse but very fine. The rod shaped structure or mitochondria could be differentiated in beta cells in such a way that they were in close correlation each other, though it was not clear to which beta granules corresponded.It was observed that the administration of sulfonamide derivatives (5) reduced as a rule the number of alpha cells, changing the degree with islet or animal. No degenerative and destructive alpha cells could be observed. On the other hand, with any dosage of S the CH-positive rod-shaped structures or Mt were observed near the sinusoidal wall when the blood sugar reached the lowest value. It can be therefore considered that these histological changes can be interpreted as the results of release of the hormone caused by stimulation of secretory activity in the cells by the administration of S.In the islets of Langerhans in the pancreas of rabbits and rats the transition from alpha cell to beta cell can be observed even in the normal state. However, with the administration of S the speed of transition seems to be accelerated and the number of beta cells was considerably increased. With the dose of 2.0g/kg, beta cells were increased quantitatively and a cluster of nuclei appeared. The appearance of vacuoles was also observed in the cell bodies.