Objective:To discuss the discrepancy of using chronic hypoxia(CH)and monocrotaline(MCT)to induce pulmonary hypertension(PH)and to explore their effects on Ca2+-sensing receptor(Ca SR). Methods:The male SD rats were randomly divided into control group(CON)

CH and MCT establishing pulmonary hypertension group. The rats in CON group were normally bred;the rats in CH group were placed in the glass box continued with 10% self-made oxygen for 21 d;the rats in MCT group were injected with 60mg/kg(BW)and were feed in SPF grade for 21 d. Mean pulmonary arterial pressure(m PAP)and right ventricular hypertrophy index(RVHI)were monitored by right heart catheterization. Expression of Ca SR m RNA and protein was detected by q PCR and Western blot. Results:Compared with that of CON group

m PAP and RVHI increased in CH and MCT group with the extending of intervening time

CH 21 d and MCT 21 d being the highest groups;m PAP and RVHI rats were significantly higher in MCT group than in CH group. Expressions of Ca SR m RNA in experimental 21 d group(CH and MCT)were significantly higher than that of CON group

higher in MCT 21 d group than in CH 21 d group. Expression of Ca SR protein increased in experimental group with the extending of intervening time

MCT 21 d being the highest group. Conclusion:Pulmonary artery pressure is higher in MCT group than in CH group in pulmonary hypertension rat model at the same time.Expressions of Ca SR m RNA and protein are positively correlated with the pulmonary artery pressure. Ca SR participates in the occurrence and development of PH.