Effect of Estradiol valerate on pancreatic beta cells resistance in diabetic female rats by streptozotocin

Diabetes mellitus (DM) is the most common metabolic disorder، with defective insulin secretion or insulin receptor function، or both. We examined the protective effect of estradiol against the destruction of pancreatic β-cells by streptozotocin (STZ). This empirical research involved 56 adult female rats (180-200 g) randomized to: group 1، food and water; group 2، olive oil injection; group 3، STZ-induced DM; group 4، castrated rats; group 5، gonadectomy + STZ; group 6، gonadal hormone + STZ; group 7، gonadal hormone + STZ + gonadal hormone. Estradiol valerate was injected intramuscularly (5 mg/kg in group 6، 4 weeks before DM induction، and 5 mg/kg in group 7، 4 weeks before and 2 weeks after DM). Diabetes was induced by 60 mg/kg، intraperitoneal STZ (STZ; 20130 Sigma-Aldrich) in citrate buffer. Data were analyzed using SPSS 16 software. In groups 6 and 7 (estradiol) blood glucose was higher than in groups 3and 5 and in group 7 was significantly higher (P ≤ 0. 05). Groups 6 and 7 also had higher serum insulin concentrations (P ≤ 0. 05) and absolute numbers of islet cells (P≤ 0. 05) compared to groups 3 and 5. Estradiol exerted a protective effect against early STZ-induced apoptotic damage to pancreatic β-cells.