Adipocyte glucocorticoid receptor has a minor contribution in adipose tissue growth

Area of Science:

• Endocrinology
• Metabolic Syndrome
• Adipose Tissue Biology

Background:

• Glucocorticoids regulate metabolism via glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) in adipocytes.
• The specific roles of GR and MR in adipose tissue expansion and obesity remain incompletely understood.

Purpose of the Study:

• To investigate the function of the glucocorticoid receptor (GR) in adipose tissue.
• To determine the contribution of adipocyte GR to diet-induced obesity and related metabolic changes.

Main Methods:

• Generation of an adipocyte-specific Gr-knockout mouse model (Gr(ad-ko)).
• Administration of standard and high-fat, high-sucrose diets to Gr(ad-ko) mice and controls.
• Assessment of body weight, adipose tissue mass, gene expression, macrophage infiltration, glucose tolerance, insulin resistance, and lipid profiles.

Main Results:

• Adipocyte-specific Gr deletion did not alter body weight gain or adipose tissue expansion.
• Lack of GR in adipocytes promoted diet-induced inflammation, evidenced by increased pro-inflammatory gene expression and macrophage infiltration.
• Adipose tissue inflammation in Gr(ad-ko) mice correlated with disturbed glucose tolerance but not insulin resistance or dyslipidemia.

Conclusions:

• Adipocyte GR is not essential for adipose tissue expansion during high-calorie diets.
• Adipocyte GR plays a role in modulating diet-induced adipose tissue inflammation and glucose homeostasis.
• Ablation of adipocyte GR affects adipose tissue function independently of its impact on overall expansion.