1. The dermal wheal response to bradykinin is increased by drugs which inhibit angiotensin-converting enzyme, and thus provides a measure of angiotensin-converting enzyme activity at the tissue level. An insertion/deletion polymorphism of the angiotensin-converting enzyme gene predicts serum angiotensin-converting enzyme activity, but its relation to angiotensin-converting enzyme activity in tissue is unclear.
2. The relations between angiotensin-converting enzyme genotype and wheal responses to intradermal bradykinin were studied in 105 healthy subjects: 30 of genotype DD, 51 of genotype ID and 24 of genotype II. Dermal wheal area was measured by digitized planimetry and the angiotensin-converting enzyme genotype by polymerase chain reaction.
3. Bradykinin produced significant linear log dose—wheal area responses. The potency of bradykinin by parallel line bioassay did not differ significantly between the genotypes; the potency in the II subjects relative to DD subjects was 1.25 (95% confidence interval: 0.83–1.88).
4. Although the angiotensin-converting enzyme gene polymorphism is a consistent and powerful predictor of serum angiotensin-converting enzyme activity, it does not appear to predict tissue angiotensin-converting enzyme activity as measured by dermal responses to bradykinin.
