Cell-specific expression of X-linked inhibitor of apoptosis in the anterior pituitary of streptozotocin-induced diabetic rats

摘要: Cell death is increased in the anterior pituitary of poorly controlled diabetic rats, but anti-apoptotic mechanisms are also activated. We hypothesized that specific cell types selectively protected against diabetes-induced death. To determine when activated, streptozotocin-induced rats were killed after 1, 4, 6 and 8 weeks evolution. Anterior pituitaries processed for western blot analysis to changes intrinsic pathway upstream kinases involved protection mechanisms. An increase was detected by ELISA at 4 diabetes. TUNEL labelling demonstrated this corresponded primarily lactotrophs, a few somatotrophs, no thyrotrophs, corticotrophs or gonadotrophs. Levels phosphorylated (p) Akt 1 week diabetes, while pERK1/2 levels pJNK weeks. Activation caspase 3 decreased members Bcl-2 protein family as early diabetes onset. These coincident with IGF-I receptor levels. X-linked inhibitor apoptosis (XIAP) significantly did activation nuclear factor (NF)kappaB. Double immunohistochemistry indicated XIAP expressed less than 1% lactotrophs gonadotrophs, approximately 50% somatotrophs more 90% thyrotrophs. results suggest some survival rapidly activated pituitary, even before can be detected, others delayed. Furthermore, both expression protective such cell-type specific.