Circulating Asprosin Declines During 24 Months of Growth Hormone Replacement and Is Associated with IGF-1 and Metabolic Remodeling in Adults with Growth Hormone Deficiency.

Adult growth hormone deficiency (GHD) is characterized by insulin resistance, visceral adiposity, and adverse body composition. Asprosin (ASP), an adipokine involved in glucose homeostasis and energy metabolism, has emerged as a potential biomarker of metabolic dysfunction. This study investigated longitudinal changes in circulating ASP and their relationships with metabolic, body composition, and bone parameters during 24 months of recombinant human growth hormone (rhGH) therapy. Nineteen adults with severe GHD were prospectively evaluated before and during rhGH replacement. Serum ASP, insulin-like growth factor-1 (IGF-1), metabolic and lipid parameters were assessed, while body composition and bone indices were determined by dual-energy X-ray absorptiometry. Associations between ASP and clinical variables were analyzed using Spearman's rank correlation. RhGH therapy significantly reduced circulating ASP concentrations at 12 and 24 months, while IGF-1 concentrations increased significantly throughout follow-up. Body fat percentage and fat mass decreased, whereas lean mass increased after 24 months of treatment. Significant changes in bone mineral content and lumbar spine Z-score were also observed after 24 months. ASP was consistently inversely correlated with fasting glucose and developed negative associations with IGF-1 and fat mass during follow-up. Time-dependent associations were also observed with visceral adiposity and lipid parameters, whereas no consistent associations between ASP and skeletal parameters were identified. Long-term rhGH replacement was associated with sustained reductions in circulating ASP concentrations and metabolic remodeling. These findings suggest that ASP may represent a candidate marker of metabolic adaptation during rhGH replacement, although validation in larger prospective cohorts is required.