Corticotropin-releasing Hormone ReceptorSubtypes in the Rat Anterior Pituitaryafter Two Types of Restraint Stress

摘要

The stress response in anterior pituitary (AP) is mediated by corticotropin-releasing hormone (CRH) acting through CRH-Rl and -R2, however, the function of CRH-R2 in AP is still not fully elucidated. We used 1-h long restraint (IMO) as well as restraint combined with water immersion (IMO+C). Using real-time PCR we quantified mRNA expression of CRH-R1, CRH-R2a-soluble and -insoluble, and cAMP response element binding (CREB), with reference gene GAPDH. In control AP, CRH-Rl mRNA was up to 20-fold higher than levels of CRH-R2a-soluble or CRH-R2a-insoluble mRNA. IMO reduced CRH-Rl mRNA to 47% and 63% of control levels 1 and 2 h after the onset of stressor, respectively, while IMO+C did not produce significant changes. Our data demonstrated that these stressors did not change CRH-R2a mRNA, unlike the very significant response of CRH-Rl to IMO.