Julie Bucher

Peak oxygen uptake test in the assessment of growth hormone deficiency.

This study aimed at evaluating a peak oxygen uptake test as a simple diagnostic tool to assess growth-hormone deficiency (GHD) in adults. Based on the findings of multiple growth hormone (GH) samplings after the exercise, a single GH sample taken 15 min postexercise revealed high accuracy in the diagnosis of GHD in the present study. A standardized peak oxygen uptake test may, therefore, provide an accurate alternative to more invasive tests of GHD.

Impaired repletion of intramyocellular lipids in patients with growth hormone deficiency after a bout of aerobic exercise

BACKGROUND Ectopic lipids such as intramyocellular lipids (IMCL) are depleted by exercise and repleted by diet, whereas intrahepatocellular lipids (IHCL) are increased immediately after exercise. So far, it is unclear how ectopic lipids behave 24 h after exercise and whether the lack of growth hormone (GH) significantly affects ectopic lipids 24 h after exercise. METHODS Seven male patients with growth hormone deficiency (GHD) and seven sedentary male control subjects (CS) were included. VO2max was assessed by spiroergometry; visceral and subcutaneous fat by whole body MRI. 1H-MR-spectroscopy was performed in M. vastus intermedius and in the liver before and after 2 h of exercise at 50% VO2max and 24 h thereafter, while diet and physical activity were standardized. RESULTS Sedentary male subjects (7 GHD, 7 CS) were recruited. Age, BMI, waist circumference, visceral and subcutaneous fat mass was not significantly different between GHD and CS. VO2max was significantly lower in GHD vs. CS. IMCL were diminished through aerobic exercise in both groups: (-11.5 ± 21.9% in CS; -8.9% ±19.1% in GHD) and restored after 24 h in CS (-5.5 ± 26.6% compared to baseline) but not in GHD (-17.9 ± 15.3%). IHCL increased immediately after exercise and decreased to baseline within 24 h. CONCLUSION These findings suggest that GHD may affect repletion of IMCL 24 h after aerobic exercise.

Short-term exercise-induced GH response in athletes: differential results for runners and bikers when tested on bicycle

As previously shown a standardized aerobic exercise of moderate intensity and a duration of around 60 minutes is a reliable test with high diagnostic accuracy in predicting severe growth hormone (GH) deficiency (GHD) in adult individuals. To improve clinical applicability of exercise testing in the diagnosis of GHD a shorter test protocol would be preferable. The present study investigated the exercise-induced GH response in healthy athletes during an incremental VO2 peak testing on a bicycle. We hypothesized that GH response would be smaller in bikers investigated on the bicycle compared with their running counterparts.