Adipose angiotensinogen secretion, blood pressure, and AGT M235T polymorphism in obese patients

Objective: To investigate AGT secretion in cultured adipocytes from obese patients and its relationship with obesity-related phenotypes, blood pressure, and the M235T polymorphism in the AGT gene. Research Methods and Procedures: Measurements, including anthropometry, body composition (DXA), and blood pressure, were performed in 61 overweight or obese women (BMI: 28 to 68 kg/m2). A subcutaneous abdominal adipose tissue biopsy was used for adipocyte size determination and quantification of AGT secretion in the medium of cultured adipocytes. AGT M235T genotype was determined using polymerase chain reaction-restriction fragment length polymorphism. Results: Adipose secretion of the AGT protein (range, 140 to 2575 ng/106 cells/24 h) was not significantly correlated with BMI, body fat, or blood pressure and did not vary according to the M235T polymorphism in the AGT gene. However, the AGT M235T polymorphism was associated with adipocyte size (111.6 ± 2.8, 108.8 ± 1.9, 118.2 ± 2.6 μm in MM, MT, and TT genotypes, respectively; p < 0.01) after adjustment for age and fat mass. An association between the AGT M235T polymorphism and adipocyte size (p < 0.02 adjusted for sex, age, and BMI) was found in another independent sample of 106 obese subjects (sex ratio, M/F 16/90; BMI, 29 to 70 kg/m2). Discussion: In cultured adipocytes from obese subjects, AGT secretion was not associated with body fat phenotypes, blood pressure, or fat cell size. However, results from two independent studies suggest an association between the AGT M235T polymorphism and adipocyte size.