title: G-protein β3-subunit gene variant, blood pressure and erythrocyte sodium/lithium countertransport in essential hypertension.
abstract: Recently, a C825T polymorphism in the gene coding for the β3 subunit of G proteins (GNB3) has been described in cells from patients with essential hypertension and enhanced Na+/H+exchange activity. This study aims to evaluate the association between the 825T allele and activity of erythrocyte sodium/lithium countertransport (Na+/Li+CT) and other sodium transport systems in red blood cells from patients with essential hypertension. A group of 77 patients (36 male, 41 female; aged 51.7 ± 1.1 years) was studied. The maximal rates (Vmax) of Na+/Li+CT, Na+/K+/Cl-cotransport and Na+K+ATPase were evaluated in erythrocytes from all the patients. They were genotyped for the C825T polymorphism by a polymerase chain reaction (PCR) method, followed by digestion with BseDI. Body mass index (BMI) was higher in CT+TT patients than in CC patients (28.9 ± 0.5 vs. 27.0 ± 0.7 kg/m2; P=0.023). Hypertensives with the T allele (CT+TT genotypes) showed significantly higher systolic blood pressure (BP) values (156.9 ± 2.1 vs. 148.9 ± 2.8 mmHg; P=0.024), whereas differences in diastolic BP did not reach statistical significance (96.4 ± 1.0 vs. 94.0 ± 1.1 mmHg; P=0.120). No differences in the Vmaxof Na+/Li+CT between the genotypes was seen (CC: 236 ± 19 and CT+TT 277 ± 23 mmol/L cells per h; P=0.221). Similarly, no differences were detected in the Vmaxof erythrocyte Na+/K+/Cl-cotransport and Na+K+ATPase among the genotypes. There was no appreciable association between the G-protein β3-subunit C825T polymorphism and erythrocyte Na+/Li+CT and other sodium transport systems in the hypertensive patient sample studied; however, those with the T allele were more obese and had more severe systolic hypertension.
authors: a Servicio de Nefrología , Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universidad de Barcelona , Spain .
authors: Esteban
authors: E
authors: Poch
authors: a Servicio de Nefrología , Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universidad de Barcelona , Spain .
authors: Daniel
authors: D
authors: González-Núñez
authors: b Unidad de Hipertensión, Servicio de Medicina Interna , Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universidad de Barcelona , Spain.
authors: Montserrat
authors: M
authors: Compte
authors: b Unidad de Hipertensión, Servicio de Medicina Interna , Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universidad de Barcelona , Spain.
authors: Alejandro De La
authors: A
authors: Sierra
keywords: GTP-binding proteins; Hypertension; Lithium; Obesity; Polymorphism (genetics); Sodium