Acute growth hormone administration causes exaggerated increases in plasma lactate and glycerol during moderate to high intensity bicycling in trained young men
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Acute growth hormone administration causes exaggerated increases in plasma lactate and glycerol during moderate to high intensity bicycling in trained young men. / Lange, Kai Henrik Wiborg; Larsson, Benny; Flyvbjerg, Allan; Dall, Rolf; Bennekou, Morten; Rasmussen, Michael Højby; Ørskov, Hans; Kjaer, Michael.
I: The Journal of clinical endocrinology and metabolism, Bind 87, Nr. 11, 11.2002, s. 4966-75.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Acute growth hormone administration causes exaggerated increases in plasma lactate and glycerol during moderate to high intensity bicycling in trained young men
AU - Lange, Kai Henrik Wiborg
AU - Larsson, Benny
AU - Flyvbjerg, Allan
AU - Dall, Rolf
AU - Bennekou, Morten
AU - Rasmussen, Michael Højby
AU - Ørskov, Hans
AU - Kjaer, Michael
PY - 2002/11
Y1 - 2002/11
N2 - We studied the acute effects of a single, sc GH dose on exercise performance and metabolism during bicycling. Seven highly trained men [age, 26 +/- 1 yr (mean +/- SEM); weight, 77 +/- 3 kg; maximal oxygen uptake, 65 +/- 1 ml O(2).min(-1).kg(-1)] performed 90 min of bicycling 4 h after receiving 7.5 IU (2.5 mg) GH or placebo in a randomized, double-blinded, cross-over design trial. A standardized pre-exercise meal was given 2 h before exercise. Blood was sampled at rest and during exercise and analyzed for GH, IGF-I, glucose, lactate, insulin, glycerol, and nonesterified fatty acids (NEFA). In the placebo trial, all subjects completed the exercise protocol without any difficulties. In contrast, two subjects were not able to complete the exercise protocol in the GH trial, and one subject barely managed to complete the protocol. In addition, GH administration resulted in exaggerated increases in plasma lactate concentrations during exercise (P < 0.0001). The combined lipolytic effect of GH and exercise, evidenced by increased plasma glycerol and serum NEFA concentrations, was 3-fold greater than the effect of exercise alone (P < 0.0001), but this increased substrate availability did not result in increased whole body fat oxidation (indirect calorimetry). Plasma glucose was, on average, 9% higher during exercise after GH administration compared with placebo (P < 0.0001). We conclude that a single, relevant GH dose causes exaggerated increases in plasma lactate and glycerol as well as serum NEFA during 90 min of subsequent bicycling at moderate to high intensity. The exaggerated increase in plasma lactate may be associated with substantially decreased exercise performance.
AB - We studied the acute effects of a single, sc GH dose on exercise performance and metabolism during bicycling. Seven highly trained men [age, 26 +/- 1 yr (mean +/- SEM); weight, 77 +/- 3 kg; maximal oxygen uptake, 65 +/- 1 ml O(2).min(-1).kg(-1)] performed 90 min of bicycling 4 h after receiving 7.5 IU (2.5 mg) GH or placebo in a randomized, double-blinded, cross-over design trial. A standardized pre-exercise meal was given 2 h before exercise. Blood was sampled at rest and during exercise and analyzed for GH, IGF-I, glucose, lactate, insulin, glycerol, and nonesterified fatty acids (NEFA). In the placebo trial, all subjects completed the exercise protocol without any difficulties. In contrast, two subjects were not able to complete the exercise protocol in the GH trial, and one subject barely managed to complete the protocol. In addition, GH administration resulted in exaggerated increases in plasma lactate concentrations during exercise (P < 0.0001). The combined lipolytic effect of GH and exercise, evidenced by increased plasma glycerol and serum NEFA concentrations, was 3-fold greater than the effect of exercise alone (P < 0.0001), but this increased substrate availability did not result in increased whole body fat oxidation (indirect calorimetry). Plasma glucose was, on average, 9% higher during exercise after GH administration compared with placebo (P < 0.0001). We conclude that a single, relevant GH dose causes exaggerated increases in plasma lactate and glycerol as well as serum NEFA during 90 min of subsequent bicycling at moderate to high intensity. The exaggerated increase in plasma lactate may be associated with substantially decreased exercise performance.
KW - Adult
KW - Bicycling
KW - Blood Glucose/analysis
KW - Cross-Over Studies
KW - Double-Blind Method
KW - Exercise
KW - Fatty Acids, Nonesterified/blood
KW - Glycerol/blood
KW - Heart Rate
KW - Hematocrit
KW - Human Growth Hormone/administration & dosage
KW - Humans
KW - Insulin/blood
KW - Insulin-Like Growth Factor I/analysis
KW - Lactic Acid/blood
KW - Male
KW - Oxygen Consumption
KW - Physical Endurance
KW - Placebos
U2 - 10.1210/jc.2001-011797
DO - 10.1210/jc.2001-011797
M3 - Journal article
C2 - 12414860
VL - 87
SP - 4966
EP - 4975
JO - Journal of Clinical Endocrinology and Metabolism
JF - Journal of Clinical Endocrinology and Metabolism
SN - 0021-972X
IS - 11
ER -
ID: 193672555