ABSTRACT
Background: Hypertensive states could result from constitutive activation of mineralorticoid receptor (MR) that generates salt retention and blood pressure elevation. Moreover, microsatellite regions can be associated to the regulation of the gene expression, producing subtle pathologies. Aim: To determine the influence of microsatellite marker AGAT of the mineralocorticoid receptor gene in the plasma renin activity (PRA) and serum aldosterone (SA) levels of essential hypertensives (HT). Patients and Methods: We studied 292 HT patients and 57 normotensive (NT) controls. Blood samples were collected for PRA, SA and DNA isolation. Subjects were genotyped according to the length of the tetranucleotide AGAT repeat using polymerase chain reaction and polyacrylamide gel electrophoresis. Based on the normal distribution, we considered 13 to 15 repeats as a habitual (H) length and less than 13 or more than 15 repeats, as non-habitual (non-H). Results: We detected 8 different lengths in the AGAT repeat (allele) in both groups, ranging from 9-17 repeats, where the allele 11 was not detected in either hypertensive or normotensive groups. The allelic distribution was different in both groups (c2=37.57, 4GL, p <0.001). In hypertensive patients, the H group showed higher PRA levels (median (Q1-Q3)) than the non-H group: 1.3 (0-7-3.5) vs 1.0 (0.5-2.3) ng/mL*h, p <0.05. The SA levels did not show differences between both groups, but the SA*PRA product was higher in the H group than the no-H group: 9.3 (3.0-24.6) vs 6.5 (2.5-14.6) p <0.05. In normotensive patients, no differences were observed in PRA, SA and SA*PRA between both groups. Conclusion: These results show association between the length of the AGAT repeat with the PRA in HT, suggesting a plausible role in the control of the MR gene expression, and secondarily in the regulation of blood pressure .