Endocrine Abstracts

Introduction: Obesity is known to be associated with hypogonadotropic hypogonadism. Hypogonadism is an established risk factor for cardio vascular disease and Type 2 Diabetes Mellitus (T2DM). However there is paucity on the evidence on improvement in testosterone with bariatric surgery. We report two patients with normalisation of testosterone after bariatric surgery.

Case Reports: Patient One 69 year old with BMI 40 and T2DM, hypertension, ischaemic heart disease and erectile dysfunction was assessed in obesity clinic. Testosterone levels were low on two occasions (4.7 and 5.8 nmol/l). FSH and LH were inappropriately low on both occasions (FSH: 3.2 and 4.3 IU/L; LH 2.2 and 1.9 IU/L). Two months post laparoscopic sleeve gastrectomy, testosterone levels normalized at 9.5 nmol/l (FSH 3.7 IU/L, LH 3.3 IU/L and SHBG 28). Patient two 54 years old with BMI 51, T2DM, erectile dysfunction and hypertension needing testosterone replacements and tadalafil seen to have hypogonadotropic hypogonadism on referral. Improvements in testosterone (3.3 to 14.2 nmol/l) were noted post laparoscopic gastric bypass (FSH <0.1 to 7.5 IU/L and LH 0.1 to 5.8 IU/L) in parallel with weight loss (57 kg, BMI from 51.4 to 33.7).

Discussion: Testosterone levels are inversely proportional to the BMI. Suppression of gonadotropins by increased leptin from adipose tissue, reduction in bio available testosterone from SHBG alterations, increased aromatase activity and association with sleep apnoea causing reduction in early morning testosterone surge are some causes for hypogonadism in obesity.

Conclusion: This is one of the first reports on normalisation of testosterone levels with weight loss after bariatric surgery. Further large scale data is needed to look into the long term vascular and metabolic health benefits.

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.