title: GH secretion in acute exercise may result in post-exercise lipolysis.
abstract: Exercise is a potent stimulator of growth hormone (GH) secretion. We hypothesised that after a short bout of intense exercise GH may increase lipolysis during recovery. In 7 moderately trained young male subjects (21.8 +/- 0.5 years) and 7 moderately trained older male subjects (56.0 +/- 1.0 years) [(2)H(5)] glycerol was infused for 370min to measure glycerol production rate (R(a)), a measure of lipolysis. At 130 min subjects exercised on a cycle ergonometer for 20 min at 70% V(O2 max), followed by rest for 220 min. On a separate occasion the study was repeated in the young subjects with a 1h GH infusion (4microgkg(-1)h(-1)) at 130 min instead of exercise. In response to exercise, catecholamines (p < 0.02) and glycerol R(a) (p < 0.01) increased, peaking during exercise. GH concentration increased in response to exercise (p < 0.01), peaking after exercise (150-160 min) in both groups with no significant difference in peak response between groups. A post-exercise rise in glycerol R(a) was demonstrated in both groups peaking at 265-295 min in the older group (p < 0.002, peak vs. basal) and continuing to rise until 370 min in the young group (p < 0.01, peak vs. basal). The timing and magnitude of this was reproduced with the GH infusion. There was a significant correlation between the peak GH response to exercise and the post-exercise rise in glycerol R(a) measured as area under the curve (r=0.57, p < 0.04). In conclusion, this study provides evidence that the GH response to acute exercise may increase lipolysis during recovery.
authors.affiliation: Department of Diabetes, Endocrinology and Internal Medicine, St. Thomas' Hospital, GKT School of Medicine, Kings College, London, UK.
authors.forename: Jamie
authors.initials: J
authors.lastname: Wee
authors.forename: Catherine
authors.initials: C
authors.lastname: Charlton
authors.forename: Helen
authors.initials: H
authors.lastname: Simpson
authors.forename: Nicola C
authors.initials: NC
authors.lastname: Jackson
authors.forename: Fariba
authors.initials: F
authors.lastname: Shojaee-Moradie
authors.forename: Michael
authors.initials: M
authors.lastname: Stolinski
authors.forename: Claire
authors.initials: C
authors.lastname: Pentecost
authors.forename: A Margot
authors.initials: AM
authors.lastname: Umpleby
mesh_terms: D000328:Adult; D000367:Age Factors; D000375:Aging; D001642:Bicycling; D001823:Body Composition; D015992:Body Mass Index; D002395:Catecholamines / Q000378:metabolism; D004837:Epinephrine / Q000378:metabolism; D015444:Exercise; D005080:Exercise Test; D005990:Glycerol / Q000737:chemistry / Q000378:metabolism; D013006:Growth Hormone / Q000378:metabolism* / Q000502:physiology*; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007554:Isotopes; D008066:Lipolysis; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000378:metabolism; D010101:Oxygen Consumption; D010806:Physical Education and Training; D005082:Physical Exertion; D010829:Physiological Phenomena; D012146:Rest; D013997:Time Factors
chemical_list: D002395:Catecholamines; D007328:Insulin; D007554:Isotopes; D013006:Growth Hormone; D005990:Glycerol; D009638:Norepinephrine; D004837:Epinephrine