Overfeeding-induced weight gain elicits decreases in sex hormone-binding globulin in healthy males-Implications for body fat distribution.

Abstract

OBJECTIVE:

Obesity and upper-body fat elevates cardiometabolic risk. However, mechanisms predisposing to upper-body fat accumulation are not completely understood. In males, low testosterone (T) frequently associates with obesity, and estrogen deficiency may contribute to upper-body adiposity. This study examines the effects of overfeeding-induced weight gain on changes in gonadal hormones in healthy males and its association with regional fat depots.

METHODS:

Twenty-five males (age: 29.7 ± 6.9 years; BMI: 24.7 ± 3.1 kg/m2 ) were overfed for 8 weeks to gain approximately 5% body weight. Changes in total and regional fat depots were assessed using dual-energy x-ray absorptiometry and abdominal computed tomography scans. Circulating T, estrone (E1), 17-β estradiol (E2), and sex hormone-binding globulin (SHBG) concentrations were measured at baseline and after weight gain.

RESULTS:

Overfeeding resulted in 3.8 (3.3, 4.9) kg weight gain with increased total body fat. Weight gain did not alter circulating T (p = 0.82), E1 (p = 0.52), or E2 (p = 0.28). However, SHBG decreased (p = 0.04) along with consequent increases in T/SHBG (p = 0.02) and E2/SHBG (p = 0.03) ratios. Importantly, baseline E2/SHBG ratio was inversely associated with increases in upper-body fat mass (ρ = -0.43, p = 0.03).

CONCLUSIONS:

Modest weight gain does not alter circulating gonadal hormones in males but may increase bioavailability of T and E2 via decreases in SHBG. The association between baseline E2/SHBG and regional fat mass suggests that higher levels of bioavailable E2 may protect from upper-body fat accumulation during overfeeding-induced modest weight gain in healthy males. Our study suggests a complex relationship between adipose tissue, gonadal hormones, and fat accumulation in males.

• Authors: Prachi Singh, Naima Covassin, Fatima H Sert-Kuniyoshi, Kara L Marlatt, Abel Romero-Corral, Diane E Davison, Ravinder J Singh, Michael D Jensen, Virend K Somers
• Journal: Physiological reports (Physiol Rep) Vol. 9 Issue 23 Pg. e15127 (12 2021) ISSN: 2051-817X [Electronic] United States
• PMID: 34877821 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © 2021 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.

Chemical References

• Sex Hormone-Binding Globulin
• Testosterone
• Estradiol

Topics

• Absorptiometry, Photon
• Adipose Tissue (diagnostic imaging, physiopathology)
• Adult
• Body Fat Distribution
• Estradiol (blood)
• Humans
• Male
• Middle Aged
• Obesity (blood, diagnostic imaging, physiopathology)
• Sex Hormone-Binding Globulin (metabolism)
• Testosterone (blood)
• Weight Gain (physiology)
• Young Adult