The effect of hyperinsulinaemic-euglycaemic clamp and exercise on bone remodeling markers in obese men.
Bone remodelling markers (BRMs) are suppressed following a glucose load and during glucose infusion. As exercise increases indices of bone health and improves glucose handling, we hypothesised that, at rest, hyperinsulinaemic-euglycaemic clamp will suppress BRMs in obese men and that exercise prior to the clamp will prevent this suppression. Eleven obese nondiabetic men (age 58.1±2.2 years, body mass index=33.1±1.4 kg m(-2) mean±s.e.m.) had a hyperinsulinaemic-euglycaemic clamp (HEC) at rest (Control) and 60 min post exercise (four bouts × 4 min cycling at 95% of hazard ratiopeak). Blood samples were analysed for serum insulin, glucose, bone formation markers, total osteocalcin (tOC) and procollagen type 1 N-terminal propeptide (P1NP), and the bone resorption marker, β-isomerised C-terminal telopeptides (β-CTx). In the control trial (no exercise), tOC, P1NP and β-CTx decreased with HEC by >10% compared with baseline (P<0.05). Fasting serum glucose, but not insulin, tended to correlate negatively with the BRMs (β range -0.57 to -0.66, p range 0.051-0.087). β-CTx, but not OC or P1NP, increased within 60 min post exercise (∼16%, P<0.01). During the post-exercise HEC, the glucose infusion rate was ∼30% higher compared with the no exercise trial. Despite this, BRMs were only suppressed to a similar extent as in the control session (10%). HEC suppressed BRMs in obese men. Exercise did not prevent this suppression of BRMs by HEC but improved glucose handling during the trial. It remains to be tested whether an exercise intervention of longer duration may be able to prevent the effect of HEC on bone remodelling.
Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University , Melbourne, Victoria, Australia ; Australian Institute of Musculoskeletal Science, North West Academic Centre, The University of Melbourne, Western Health , Melbourne, Victoria, Australia.
Itamar
I
Levinger
Department of Physiology, Bosch Institute for Medical Research, University of Sydney , Sydney, New South Wales, Australia.
Tara C
TC
Brennan-Speranza
University of Melbourne and the Department of Endocrinology, Austin Health , Melbourne, Victoria, Australia.
George
G
Jerums
Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University , Melbourne, Victoria, Australia.
Nigel K
NK
Stepto
Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University , Melbourne, Victoria, Australia.
Fabio R
FR
Serpiello
Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University , Melbourne, Victoria, Australia ; Australian Institute of Musculoskeletal Science, North West Academic Centre, The University of Melbourne, Western Health , Melbourne, Victoria, Australia ; College of Health and Biomedicine, Victoria University , Melbourne, Victoria, Australia.
Glenn K
GK
McConell
Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University , Melbourne, Victoria, Australia.
Mitchell
M
Anderson
University of Melbourne and the Department of Cardiology, Austin Health , Melbourne, Victoria, Australia.
David L
DL
Hare
PathWest QEII Medical Centre , Perth, Western Australia, Australia.
Elizabeth
E
Byrnes
Australian Institute of Musculoskeletal Science, North West Academic Centre, The University of Melbourne, Western Health , Melbourne, Victoria, Australia ; Department of Medicine, School of Clinical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria , Australia.
Peter R
PR
Ebeling
University of Melbourne and the Department of Endocrinology, Austin Health , Melbourne, Victoria, Australia.
Ego
E
Seeman