Leptin-induced changes in body composition in high fat-fed mice

Area of Science:

• Metabolic research
• Obesity studies
• Endocrinology

Background:

• Dietary fat content significantly impacts metabolic health.
• Leptin is a key hormone regulating energy balance and body weight.
• Understanding leptin's effects across different dietary conditions is crucial for metabolic disease research.

Purpose of the Study:

• To investigate the effects of leptin administration on adiposity and metabolic parameters in mice fed varying fat diets.
• To differentiate the impact of continuous leptin infusion versus acute leptin injection on energy intake, body weight, and insulin sensitivity.

Main Methods:

• Female C57BL/6J mice were fed either 10% or 45% kcal fat diets for 8 weeks.
• Mice received continuous intraperitoneal leptin infusion (10 micro g/day) or a single leptin injection (30 micro g).
• Glucose tolerance tests and insulin sensitivity tests were performed, with body composition and energy intake monitored.

Main Results:

• Continuous leptin infusion reduced adiposity in both low and high-fat fed mice compared to controls.
• Leptin infusion transiently inhibited food intake in low-fat fed mice but not high-fat fed mice.
• Acute leptin injection inhibited 24-hr energy intake and weight gain in all mice, irrespective of diet.
• Leptin improved insulin sensitivity in high-fat fed mice and insulin release in low-fat fed mice.

Conclusions:

• Leptin reduces adiposity independently of energy intake in high-fat fed mice.
• Leptin administration, via infusion or injection, impacts energy balance and metabolic health differently depending on the delivery method and dietary context.
• Leptin holds potential for managing obesity and improving insulin sensitivity, with delivery method being a critical factor.