[The protective effect of endogenous and exogenous somatostatin on monolayer cultured islet B cells damaged by streptozotocin].

Exogenous administration of somatostatin exerted a beneficial influence directly on monolayer cultured islet B cells damaged by streptozotocin (3.0 mmol/L). Six to twelve hours following the pretreatment with somatostatin of 0.025, 0.05 and 0.1 microgram/ml the number of viable cells was significantly increased from 41.13 +/- 0.65 x 10(4) cells/ml (STZ control) to 49.0 +/- 2.0, 53.0 +/- 1.33, 53.38 +/- 1.74 x 10(4) cells/ml, respectively. The ultrastructural appearance of the B cells indicated that with many vacuoles and granules occurred in the cytoplasma of these cells, normal organelles disappeared and the nuclei were obscure in structure. The pretreatment with somatostatin (0.1 microgram/ml) protected the B cells against streptozotocin, with mitochondria, Golgi's apparatus and granules in these cells intact. The destruction of B cells induced by streptozotocin was more severe after adding anti-somatostatin serum to neutralize the endogenous somatostatin in the culture, which was reversed by replenishment of somatostatin. Adding Ca2+ carrier A23187 did not change the protective effect of somatostatin, it seemed that there was no relationship between the protective effect of somatostatin and calcium mechanism.