Objective To investigate the relation between myocardium hypertrophy and the expression of α1G subunit of T-type calcium channels in left ventricular myocytes of 5/6 SNx rats, and the effect of calcitriol on the expression of α1G subunit of T-type calcium channels. Methods Twenty-four male Sprague-dawley rats were randomly divided into three groups(n=8): A. CRF; B.CRF administrated 50ng/d of calcitriol; C: sham-operated control. Sprague-dawley rats in group A and B underwent two-step 5/6 subtotal nephrectomy(SNx)；control rats underwent bilateral renal decapsulation. After 12 weeks,all rats were sacrificed, and the ratio of heart weight and body weight, blood urea nitrogen (BUN),serum creatinine(SCr),intact parathyroid hormone(iPTH) and creatinine clearance(CCr) were detected. Moreover, the expression of α1G subunits mRNA of T-type calcium channels were detected by RT-PCR. Results Compared to group C, the ratio of heart weight and body weight, BUN, SCr, iPTH in group A were obviously elevated (P<0.01) and CCr were significantly decreased (P<0.01); α1G subunits mRNA of T-type calcium channels were expressed again in the left ventricular myocytes of 5/6 SNx rats( P≤0.001). In group B, compared to group A, in addition to iPTH witch was predominantly decreased, the ratio of heart weight and body weight, Bun, SCr, CCr and the expression of α1G subunits mRNA were not obviously changed (P>0.05). Conclusion There are increase of heart weight and expression of T-type calcium channels in left ventricular myocytes of 5/6 SNx rats. It implies that T-type calcium channel may play an important role in myocardium hypertrophy of 5/6 SNx rats. In 12 weeks after 5/6 SNx, there were no obvious change of α1G subunits mRNA. It indicates the research on finding new-type specificic blocker of T-type calcium channel is very necessary. 