Replicability of leptin associations with testosterone, estradiol, follicle-stimulating hormone, and luteinizing hormone in healthy Ache men of Paraguay: A multiple daily assessment.

Objective: Associations between leptin and male reproductive hormone levels have been reported in men. However, few of these investigations have focused on associations in healthy men without obesity or overweight or nonindustrial societies.

Methods: We test hypotheses that leptin is associated with testosterone, estradiol, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) within healthy Ache men, an indigenous nonindustrialized South American community using archived data.

Results: Archived data of serum FSH, LH, leptin, and salivary testosterone and estradiol levels collected from healthy Ache men (n = 17, mean age = 37.1 ± 14.2) on two separate days revealed leptin was correlated with FSH (D1 p = .07, D2 p = .009) and PM testosterone (TsalPM, D1 p = .05, D2 p = .05). However, controlling for age, associations with FSH were not significant. Mean comparisons and linear regression of values over 2 days resulted in leptin (t = 0.08, p = .94, r  = .58, p = .0009), LH (t = 1.16, p = .26, r  = .11, p = .27), FSH (U = 131.5, p = .88, r  = .63, p = .0002), AM testosterone (TsalAM, t = 4.0, p = .001, r  = .02, p = 0.75), and TsalPM (t = 2.99, p = .01, r  = .56, p = .01).

Conclusion: We conclude (a) FSH, TsalPM, and leptin levels within individual men are relatively invariant over a span of days; (b) despite small sample sizes, results suggest ecological and lifestyle variation can contribute to variation in leptin associations with male reproductive hormones.