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High Sodium Intake Enhances Insulin‐stimulated Glucose Uptake in Rat Epididymal Adipose Tissue
Author(s) -
FonsecaAlaniz Miriam H.,
Takada Julie,
Andreotti Sandra,
Campos Tarcila B.F.,
Campaña Amanda B.,
BorgesSilva Cristi.,
Lima Fabio B.
Publication year - 2008
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1038/oby.2008.69
Subject(s) - medicine , endocrinology , insulin , adipose tissue , adipocyte , white adipose tissue , glucose uptake , carbohydrate metabolism , chemistry , glucose transporter , sodium , biology , organic chemistry
Objective: This study investigated the effect of different sodium content diets on rat adipose tissue carbohydrate metabolism and insulin sensitivity. Methods and Procedures: Male Wistar rats were fed on normal‐ (0.5% Na + ; NS), high‐ (3.12% Na + ; HS), or low‐sodium (0.06% Na + ; LS) diets for 3, 6, and 9 weeks after weaning. Blood pressure (BP) was measured using a computerized tail‐cuff system. An intravenous insulin tolerance test (ivITT) was performed in fasted animals. At the end of each period, rats were killed and blood samples were collected for glucose and insulin determinations. The white adipose tissue (WAT) from abdominal and inguinal subcutaneous (SC) and periepididymal (PE) depots were weighed and processed for adipocyte isolation and measurement of in vitro rates of insulin‐stimulated 2‐deoxy‐ d ‐[ 3 H]‐glucose uptake (2DGU) and conversion of ‐[U‐ 14 C]‐glucose into 14 CO 2 . Results: After 6 weeks, HS diet significantly increased the BP, SC and PE WAT masses, PE adipocyte size, and plasma insulin concentration. The sodium dietary content did not influence the whole‐body insulin sensitivity. A higher half‐maximal effective insulin concentration (EC 50 ) from the dose‐response curve of 2DGU and an increase in the insulin‐stimulated glucose oxidation rate were observed in the isolated PE adipocytes from HS rats. Discussion: The chronic salt overload enhanced the adipocyte insulin sensitivity for glucose uptake and the insulin‐induced glucose metabolization, contributing to promote adipocyte hypertrophy and increase the mass of several adipose depots, particularly the PE fat pad.