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The CSF and arterial to internal jugular venous hormonal differences during exercise in humans
Author(s) -
Dalsgaard Mads K.,
Ott Peter,
Dela Flemming,
Juul Anders,
Pedersen Bente K.,
Warberg Jørgen,
Fahrenkrug Jan,
Secher Niels H.
Publication year - 2004
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.2003.026922
Subject(s) - medicine , endocrinology , hormone , cerebrospinal fluid , physical exercise , insulin , venous blood , carbohydrate , endocrine system
Strenuous exercise increases the cerebral uptake of carbohydrate out of proportion to that of oxygen, but it is unknown whether such enhanced carbohydrate uptake is influenced by the marked endocrine response to exercise. During exhaustive exercise this study evaluated the a–v differences across the brain (a–v diff) of hormones that could influence its carbohydrate uptake ( n = 9). In addition, neuroendocrine activity and a potential uptake of hormones via the cerebrospinal fluid (CSF) were assessed by lumbar puncture postexercise and at rest ( n = 6). Exercise increased the arterial concentration of noradrenaline and adrenaline, but there was no cerebral uptake. However, following exercise CSF noradrenaline was 1.4 (0.73–5.5) nmol l −1 , and higher than at rest, 0.3 (0.19–1.84) nmol l −1 ( P < 0.05), whereas adrenaline could not be detected. Exercise increased both the arterial concentration of NH 4 + and its a–v diff, which increased from 1 (–12 to 5) to 17 (5–41) μmol l −1 ( P < 0.05), while the CSF NH 4 + was reduced to 7 (0–10) versus 11 (7–16) μmol l −1 ( P < 0.05). There was no release from, or accumulation in the brain of interleukin (IL)‐6, tumour necrosis factor (TNF‐α), heatshock protein (HSP72), insulin, or insulin‐like growth factor (IGF)‐I. The findings indicate that for maximal exercise, the concentration of noradrenaline is increased within the brain, whereas blood borne hormones and cytokines are seemingly unimportant. The results support the notion that the exercise‐induced changes in brain metabolism are controlled by factors intrinsic to the brain.