Blood collection and analysis
Tecan
Vein blood was collected in the morning of each study meeting in a fasted state by certified personnel. After centrifugation, plasma was stored at −80°C until needed for analysis. Selected hormone concentrations in the plasma were determined using commercially available ELISA kits: EIA1887 for cortisol, EIA4140 for insulin-like growth factor 1 (IGF-1), and EIA1787 for testosterone (DRG International, Springfield, NJ, USA). Absorbance was determined with a microplate reader and associated software (Infinite Pro 200 with i-control, Tecan, Austria).