J.A. ZOLADZ1, A. PILC2, J. MAJERCZAK1, M. GRANDYS1, J. ZAPART-BUKOWSKA1, K. DUDA1, 3
ENDURANCE TRAINING INCREASES PLASMA BRAIN-DERIVED NEUROTROPHIC FACTOR CONCENTRATION IN YOUNG HEALTHY MEN
Department of Physiology and Biochemistry, University School of Physical Education, Krakow, Poland; 2Institute ofPharmacology, Polish Academy of Science, Krakow, Poland; 3Cancer Institute, Krakow, Poland. It is believed that brain derived neurotrophic factor (BDNF) plays an important role in neuronal growth, transmission, modulation and plasticity. Single bout of exercise can increase plasma BDNF concentration [BDNF]p in humans. It was recently reported however, that elevated [BDNF]p positively correlatedwith risk factors for metabolic syndrome and type 2 diabetes mellitus in middle age group of subjects. On the other hand it is well established that endurance training decreases the risk of diabetes and development of metabolic syndrome. In the present study we have examined the effect of 5 weeks of moderate intensity endurance training on the basal and the exercise induced changes in [BDNF]p inhumans. Thirteen young, healthy and physically active men (mean ± S.E: age 22.7 ± 0.5 yr, body height 180.2 ± 1.7 cm, body weight 77.0 ± 2.5 kg, Vo2max 45.29 ± 0.93 ml . kg-1 . min-1) performed a five week endurance cycling training program, composed mainly of moderate intensity bouts. Before training [BDNF]p at rest have amounted to 10.3 ± 1.4 pg . ml-1. No effect of a single maximal incrementalcycling up to Vo2max on its concentration was found (10.9 ± 2.3 pg . ml-1, P=0.74). The training resulted in a significant (P=0.01) increase in [BDNF]p at rest to 16.8 ± 2.1 pg . ml-1, as well as in significant (P=0.0002) exercise induced increase in the [BDNF]p (10.9 ± 2.3 pg . ml-1 before training vs. 68.4 ± 16.0 pg . ml-1 after training). The training induced increase in resting [BDNF]p wasaccompanied by a slight decrease in insulin resistance (P=0.25), calculated using the homeostatic model assessment version 2 (HOMA2-IR), amounting to 1.40 ± 0.13 before and 1.15 ± 0.13 after the training. Moreover, we have found that the basal [BDNF]p in athletes (n=16) was significantly higher than in untrained subjects (n=13) (29.5 ± 9.5 pg . ml-1 vs. 10.3 ± 1.4 pg . ml-1, P=0.013). We have concludedthat endurance training of moderate intensity increases both basal as well as the end-exercise [BDNF]p in young healthy men. This adaptive response, contrariwise to the recent findings in patients with metabolic disorders, was accompanied by a slight decrease in insulin resistance. K e y w o r d s : brain derived neurotrophic factor, exercise, insulin, training
Brainderived neurotrophic factor (BDNF) was first isolated from pig brain (1) and is the most abundant in the nerve growth factor family. BDNF is related to nerve growth factor, the first neurotrophic factor discovered (2) and acts via protein tyrosine kinase receptor (TrkB) (3). BDNF and other trophic factors may play a role in preventing neuronal death and in processes of neuroregeneration (4). Itpromotes the development of immature neurons and enhances the survival of adult ones (5). BDNF plays a role in memory formation (7), synaptic plasticity (6), synapse formation (8), synaptic efficacy and neuronal connectivity (9). In the periphery BDNF is found in the plasma, serum and platelets (10) and it is formed by vascular endothelial cells and by peripheral blood mononuclear cells (11). Despitethe size of the protein (27 kDa) BDNF can cross the blood-brain barrier (12, 13) in both directions from brain to the periphery and from the periphery to the brain (13), via high capacity saturable transporter system (13). A positive correlation between BDNF levels in the brain and serum was described (14), therefore the blood levels of BDNF may reflect the brain levels and viceversa. It should be...