Caronia LM, Dwyer AA, Hayden D, Amati F, Pitteloud N, Hayes FJ.
Feb 1, 2013
Clinical Endocrinology (Oxf). 2013;78(2):291-296. doi:10.1111/j.1365-2265.2012.04486.x
Objective: This study examines the physiological impact of a glucose load on serum testosterone (T) levels in men with varying glucose tolerance (GT).
Design: Cross-sectional study.
Patients and methods: 74 men (19-74 years, mean 51·4 ± 1·4 years) underwent a standard 75-g oral glucose tolerance test with blood sampling at 0, 30, 60, 90 and 120 min. Fasting serum glucose, insulin, total T (and calculated free T), LH, SHBG, leptin and cortisol were measured.
Results: 57% of the men had normal GT, 30% had impaired GT and 13% had newly diagnosed type 2 diabetes. Glucose ingestion was associated with a 25% decrease in mean T levels (delta = -4·2 ± 0·3 nm, P < 0·0001). T levels remained suppressed at 120 min compared with baseline (13·7 ± 0·6 vs 16·5 ± 0·7 nm, P < 0·0001) and did not differ across GT or BMI. Of the 66 men with normal T levels at baseline, 10 (15%) had levels that decreased to the hypogonadal range (<9·7 nm) at one or more time points. SHBG, LH and cortisol levels were unchanged. Leptin levels decreased from baseline at all time points (P < 0·0001).
Conclusions: Glucose ingestion induces a significant reduction in total and free T levels in men, which is similar across the spectrum of glucose tolerance. This decrease in T appears to be because of a direct testicular defect, but the absence of compensatory changes in LH suggests an additional central component. Men found to have low nonfasting T levels should be re-evaluated in the fasting state.
Trial registration: ClinicalTrials.gov NCT00433173.
Full Text: https://pubmed.ncbi.nlm.nih.gov/22804876/
Hypergonadism, Testosterone, Glucose Tolerance
The information on this website has not been evaluated by the Food & Drug Administration or any other medical body. We do not aim to diagnose, treat, cure or prevent any illness or disease. Information is shared for educational purposes only. The content of this blog is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Users should not disregard, or delay in obtaining, medical advice for any medical condition they may have, and should seek the assistance of their health care professionals for any such conditions. You must consult your doctor before acting on any content on this website, especially if you are pregnant, nursing, taking medication, or have a medical condition.