Endurance training and GH administration in elderly women: effects on abdominal adipose tissue lipolysis

In the present study, the effect of endurance training alone and endurance training combined with recombinant human growth hormone (rhGH) administrati on on subcutaneous abdominal adipose tissue lipolysis was investigated. Six teen healthy women [age 75 +/- 2 yr (mean +/- SE)] underwent a 12-wk endura nce training program on a cycle ergometer. rhGH was administered in a rando mized, double-blinded, placebo-controlled design in addition to the trainin g program. Subcutaneous abdominal adipose tissue lipolysis was estimated by means of microdialysis combined with measurements of subcutaneous abdomina l adipose tissue blood flow (ATBF; Xe-133 washout). Whole body fat oxidatio n was estimated simultaneously by indirect calorimetry. Before and after co mpletion of the training program, measurements were performed both at rest and during 60 min of continuous cycling at a workload corresponding to 60% of pretraining peak oxygen uptake. Endurance training alone did not affect subcutaneous abdominal adipose tissue lipolysis either at rest or during ex ercise, as reflected by identical levels of interstitial adipose tissue gly cerol, subcutaneous abdominal ATBF, and plasma nonesterified fatty acids be fore and after completion of the training program. Similarly, no effect on subcutaneous abdominal adipose tissue lipolysis was observed when combining endurance training with rhGH administration. However, in both the placebo and the GH groups, fat oxidation was significantly increased during exercis e performed at the same absolute workload after completion of the training program. We conclude that the changed lipid metabolism during exercise obse rved after endurance training alone or after endurance training combined wi th rhGH administration is not due to alterations in subcutaneous abdominal adipose tissue metabolism in elderly women.