The effect of GH replacement therapy on exercise capacity, fat mass, ectopic lipids intramyocellular and intrahepatocellular lipids and insulin resistance in hypopituitary patients with GH deficiency

A Egger; S Allemann; C Stettler; P Diem; T Buehler; C Boesch; E Christ

P1415

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Endocrine Abstracts (2012) 29 P1415

ICEECE2012 Poster Presentations Pituitary Clinical (183 abstracts)

The effect of GH replacement therapy on exercise capacity, fat mass, ectopic lipids intramyocellular and intrahepatocellular lipids and insulin resistance in hypopituitary patients with GH deficiency

A Egger ¹ , S Allemann ¹ , C Stettler ¹ , P Diem ¹ , T Buehler ² , C Boesch ² & E Christ ¹

Err

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¹University Hospital of Bern, Inselspital, Bern, Switzerland; ²University of Bern, Bern, Switzerland.

Introduction: Increased levels of ectopic lipids (IMCL and IHCL) have been related to insulin resistance. Aerobic exercise affects IMCL. GHRT is known to increase exercise capacity, insulin resistance and decrease fat mass. The effect of GHRT on ectopic lipids is not known.

Methods: Ten patients with GHD and ten sedentary control subjects (CS; matched for gender, age, BMI and waist) were recruited. VO_2max was assessed using an exercise test on a treadmill. Insulin sensitivity was determined by a two-step hyperinsulinaemic euglycaemic clamp. By MR-imaging visceral (VAT) and subcutaneous (SCAT) fat compartments were quantified. IHCL and IMCL were measured before and after a 2-h aerobic exercise at 50–60% of VO_2max using MR-spectroscopy. Free fatty acid concentrations (FFA) were determined during exercise. Identical investigations were performed after 6 months GHRT.

Results: Four female, 6 male GHD patients and matched CS volunteered for this study. VO_2max tended to be reduced in GHD compared to CS and significantly increased after GHRT. Basal FFA and AUC FFA during exercise were similar in GHD, CS and following GHRT. SCAT and VAT was similar in GHD and CS. GHRT significantly decreased SCAT and VAT. Pre-exercise ectopic lipid levels were similar in CS, GHD and GHRT. 2h-aerobic exercise resulted in a significant decrease in IMCL (δ-IMCL) and increase in IHCL (δ-IHCL) in CS, GHD and GHRT. GHRT did not significantly impact on δ-IMCL and δ-IHCL. HOMA-value tended to be decreased in GHD compared with CS. GHRT resulted in a non-significant increase in HOMA. Endogenous glucose production and glucose disposal rate were similar in GHD, CS and following GHRT.

Conclusions: -GHRT results in an increase in VO_2max and a decrease in SCAT and VAT.

-Aerobic exercise acutely impacts on ectopic lipids in GHD, CS and GHRT.

-Ectopic lipids (IMCL and IHCL) are similar in GHD, CS and following GHRT.

-GHD is not associated with insulin resistance when compared with CS matched for waist.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This work was supported, however funding details unavailable.