Luteinizing Hormone Suppression Profiles in Men Treated With Exogenous Testosterone.

Background: Due to the negative feedback mechanism involved in the hypothalamic-pituitary-gonadal axis, testosterone therapy (TTh) may result in suppression of luteinizing hormone (LH) secretion, but clinical experience demonstrates the level of LH suppression is variable.

Aim: We sought to define the relationship between TTh and LH levels, specifically predictors of LH suppression in men on TTh.

Methods: We performed a retrospective analysis of a prospectively maintained database of patients with testosterone deficiency (TD) treated with TTh. Patient demographic and clinical data including vascular risk factor (VRF) status were collected. Serum total T and LH levels before TTh and after ≥3 months (m) were recorded. LH suppression was defined as serum LH level <1.0 IU/ml.

Main Outcome Measures: Predictors of LH suppression were searched though a series of logistic regression models assessing suppression status at the final observation, and then a series of Cox proportional hazards models assessing time to first suppression were performed.

Results: A total of 227 patients with mean age of 58±14 years at time of TTh initiation were included in our analysis. Just under half of subjects received transdermal T as the only modality (n = 101, 44%), while one third (n = 77, 34%) received intramuscular only, and the remainder (n = 49, 22%) received both modalities during follow-up. The mean baseline LH level was 10 ± 12 IU/ml. The percent of men who had baseline LH level above 1 IU/ml and at any given point of TTh was 84% and 78%, respectively, thus 22% of men had suppressed LH levels on TTh considering the definition of LH <1 IU/ml. Most men (73%) had a suppressed LH level of <1 IU/ml at least once during follow-up. In the final adjusted model for LH suppression, intramuscular route (OR = 2.44), baseline LH (OR = 0.94), estradiol (OR = 1.05) remained significant.

Clinical Implications: LH suppression profiles may be relevant for dose titration during TTh and perhaps to minimize testicular atrophy.

Strengths & Limitations: A strict definition for TD was applied using LCMS for T measurements and patients had long-term follow-up.

Conclusion: While 73% of patients had at least one LH <1 IU/ml during TTh, only 22% maintained suppressed throughout the treatment. Miranda EP, Schofield E, Matsushita K, et al. Luteinizing Hormone Suppression Profiles in Men Treated With Exogenous Testosterone. J Sex Med 2022;19:1359-1365.