The Effect of Endurance-Type Exercise Training on Growth Mediators and Inflammatory Cytokines in Pre-Pubertal and Early Pubertal Males

Recent studies demonstrate an unexpected reduction in circulating levels of IGF-I after 5 wk of endurance-type exercise training in adolescent boys and girls and prepubertal girls. We hypothesized that the reduction in IGF-I would be accompanied by a training-associated stimulation of proinflammatory cytokines IL-1β, IL-6, or tumor necrosis factor-α (TNF-α), each of which can inhibit the GH→IGF-I axis. Healthy boys (age range 9–11 y old, mean...