Sexual dimorphism in developmental and diet-dependent circulating retinol binding protein 4.

Area of Science:

• Metabolic Research
• Endocrinology
• Obesity Studies

Background:

• Retinol Binding Protein 4 (RBP4) links obesity, insulin resistance, and related diseases like type 2 diabetes.
• Previous studies noted variable associations between RBP4 levels, body mass, and gender, often with limited dietary interventions.
• Investigating sex and age impacts on RBP4 and obesity is crucial for understanding metabolic health disparities.

Purpose of the Study:

• To investigate the impact of sex, age, and diet (high vs. low fat) on obesity, RBP4 levels, and insulin resistance in C57BL/6J mice.
• To determine if gender differences in RBP4 levels are established early and persist over time.
• To explore the relationship between gender differences in RBP4 and the development of glucose intolerance and insulin resistance.

Main Methods:

• Male and female C57BL/6J mice were fed low or high-fat diets for 400 days.
• Female mice underwent ovariectomy or sham surgery to assess hormonal influences.
• Weight, circulating RBP4, glucose, and insulin levels were monitored every 100 days, with glucose tolerance tests performed.

Main Results:

• All mice gained weight, with high-fat diets and male sex significantly increasing weight gain.
• Male mice exhibited higher RBP4 levels than females from the study's onset, a difference maintained for over a year.
• Gender differences in RBP4 correlated with significant differences in glucose intolerance and insulin resistance development.

Conclusions:

• Significant, persistent gender differences in circulating RBP4 levels exist in C57BL/6J mice from an early age.
• These RBP4 gender differences may offer a protective effect against glucose intolerance and insulin resistance in males.
• Targeting RBP4 pathways presents a potential strategy to mitigate gender-based disparities in insulin resistance and associated comorbidities.