Objective We investigated the serum activities of ACE and the insertion/deletion(I/D)polymorphism of ACE gene in 116 Han diabetics with or without hypertension. Methods I/D of the allele was amplificated by PCR

analyzed by electrophorysis; serum ACE activities were determined by spectrophotometry. Results Frequen cies of D allele were 0.63 in diabetic group with hypertension

0.51 in diabetic group

and 0.48 in control. The frequency of D allele in diabetic group with hypertension was significantly higher than those of the two other groups(P<0.05 and P<0.025). The frequencies of D allele between diabetic and control groups were not different significantly(P>0.05). The serum activities with DD genotype were higher than those of both DI and II genotype of ACE .Among the three genotypes the serum activities of ACE were different significantly(P=121.73

P<0.01). It was also the case with the three groups the serum activities of ACE also were significantly different (P=32.57

P< 0.01). Conclusion In the three groups

the high serum activities of ACE were related to the deletion in the 16th intron of ACE gene. The higher activities of ACE

the higher blood pressure. Deletion of the 16 intron of ACE gene was probably one of the factors which caused high serum activities of ACE and hypertension.