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Hormones and body composition in humans: clinical studies
F Armellini1, M Zamboni, O Bosello
1Division of Geriatrics, Hospital of Valdagno, Italy. farmel@tin.it
Summary
Leptin levels correlate with body fat percentage, showing higher values in women than men. Factors like insulin resistance, pregnancy, and aging significantly influence leptin and body fat distribution.
Area of Science:
- Endocrinology
- Metabolism
- Body Composition Research
Background:
- Leptin levels are closely linked to body fat percentage, with women exhibiting approximately double the levels observed in men.
- Hormonal factors, particularly androgens, are implicated in the gender-specific differences in leptin levels.
- Insulin resistance is a significant contributor to the variability in leptin concentrations and is associated with elevated leptin independent of body fat mass.
Purpose of the Study:
- To explore the relationship between leptin, body fat, and hormonal regulation of fat distribution.
- To investigate the influence of gender, insulin resistance, pregnancy, aging, and energy restriction on leptin levels.
- To understand the hormonal mechanisms governing triglyceride flux and intra-abdominal fat accumulation.
Main Methods:
- Analysis of leptin circulating levels in relation to body fat percentage.
- Examination of gender differences in leptin values.
- Assessment of the impact of insulin resistance, pregnancy, and aging on leptin levels and body composition.
- Evaluation of the role of hormonal balance (insulin, corticosteroids, sexual, and growth hormones) in triglyceride metabolism.
Main Results:
- Leptin levels are strongly correlated with body fat percentage, with women having twofold higher levels than men.
- Insulin resistance is associated with elevated leptin, independent of body fat mass, and leptin is related to insulin sensitivity independent of BMI.
- Energy restriction can significantly alter leptin levels, overriding changes in body composition. Hormonal shifts with aging decrease lipolytic activity, promoting visceral fat accumulation, with distinct patterns in men and postmenopausal women.
Conclusions:
- Leptin levels are a key indicator of body fat and are modulated by hormonal status, insulin sensitivity, and lifestyle factors.
- Gender, aging, and metabolic conditions like insulin resistance significantly impact leptin regulation and body fat distribution.
- Understanding these complex interactions is crucial for managing metabolic health and body composition.