Circulating free testosterone in obese men after bariatric surgery increases in parallel with insulin sensitivity

• Published in: Journal of endocrinological investigation Vol. 36; no. 4; pp. 227 - 232
• Main Authors: Botella-Carretero, J. I., Balsa, J. A., Gómez-Martin, J. M., Peromingo, R., Huerta, L., Carrasco, M., Arrieta, F., Zamarron, I., Martin-Hidalgo, A., Vazquez, C.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-04-2013; Springer Nature B.V
• Subjects: Adult; Bariatric Surgery - rehabilitation; Blood Glucose - analysis; Body weight loss; Diabetes mellitus; Endocrinology; Gastrointestinal surgery; Glucose; Humans; Hypogonadism; Hypogonadism - blood; Hypogonadism - etiology; Hypogonadism - surgery; Insulin; Insulin - blood; Insulin resistance; Insulin Resistance - physiology; Male; Medicine; Medicine & Public Health; Metabolic Diseases; Middle Aged; Obesity; Obesity - blood; Obesity - complications; Obesity - surgery; Original Article; Patients; Postoperative Period; Sensitivity analysis; Sex Hormone-Binding Globulin - analysis; Surgery; Testosterone; Testosterone - blood; Up-Regulation; testosterone; Insulin sensitivity; male hypogonadism; obesity; surgery
• ISSN: 0391-4097; 1720-8386
• DOI: 10.3275/8469

Background and aim:
Male hypogonadism has been linked to obesity and diabetes. We aimed to study the association of changes in insulin sensitivity and testosterone levels in severe obese patients submitted to bariatric surgery.
Subjects and methods:
Prospective intervention study with twenty consecutive patients who underwent bariatric surgery studied before and after significant weight loss. Serum testosterone, SHBG, fasting glucose, and insulin were measured among others. Free testosterone was calculated with the Vermeulen formula and insulin sensitivity with the homeostatic model assessment (HOMA).
Results:
At baseline, thirteen patients had low total testosterone levels, whereas eight of these patients also had free testosterone levels below the reference range obtained from the control group. After bariatric surgery total testosterone, SHBG, and free testosterone significantly increased and achieved normal values in all evaluated patients. Insulin sensitivity improved in all of them. Multivariate linear regression showed that changes in fasting glucose (β=−1.868,
p
= 0.001), insulin (β=−3.782,
p
= 0.001), weight (β=−0.622,
p
= 0.002), and SHBG (β=−0.635,
p
= 0.022) were associated with changes in free testosterone (adjusted R
2
=0.936, F=26.613,
p
= 0.001). When insulin resistance calculated by HOMA was in the model instead of insulin and glucose, it also was associated (β=−3.488,
p
= 0.008) with free testosterone (adjusted R
2
=0.821, F=11.111,
p
= 0.005).
Conclusion:
Circulating testosterone in obese men increases after bariatric surgery in parallel with an improvement in insulin sensitivity.