title: Plasma corticotrophin releasing factor and vasopressin responses to exercise in normal man.
abstract: OBJECTIVE
  To evaluate the hypothalamo-pituitary-adrenal (HPA) response to both mild and intense exercise.
  
  
  METHODS
  Maximum oxygen consumption (VO2max.) was initially determined. Exercise to 20% (mild) and 90% (intense) VO2max. was undertaken in random order. Subjects were exercised over a 5-minute period to the required level of intensity, which was maintained for a further 10 minutes.
  
  
  METHODS
  Six trained male athletes.
  
  
  METHODS
  Brachial vein blood was sampled before and at 5-minute intervals during and after exercise and assayed for plasma cortisol, ACTH, arginine vasopressin (AVP), corticotrophin releasing factor (CRF), sodium and lactate levels. Haemoglobin and haematocrit were measured before and at the end of exercise. Heart rate was monitored continuously and blood pressure measured whenever blood was sampled before and after exercise.
  
  
  RESULTS
  Maximum heart rate was 184 +/- 2 and 82 +/- 5 (mean +/- SEM) beats per minute at 90 and 20% VO2max. respectively. Plasma volume fell by 8.7 +/- 2.4% with intense exercise. Significant increases in plasma concentrations of AVP, ACTH and cortisol, but not CRF, occurred during intense exercise. Plasma sodium concentration, which increased during intense but not mild exercise, peaked at 10 minutes after the onset of exercise and preceded the rise in plasma AVP. The AVP peak clearly preceded the ACTH peak in two subjects and occurred synchronously with it in three subjects.
  
  
  CONCLUSIONS
  These results indicate that although significant HPA activation occurs during intense exercise, CRF does not appear to play a major role in mediating the ACTH response to an acute episode of vigorous exercise in man. AVP may be more important in this regard.
authors.affiliation: Department of Endocrinology, Princess Margaret Hospital, Christchurch, New Zealand.
authors.forename: G A
authors.initials: GA
authors.lastname: Wittert
authors.forename: D E
authors.initials: DE
authors.lastname: Stewart
authors.forename: M P
authors.initials: MP
authors.lastname: Graves
authors.forename: M J
authors.initials: MJ
authors.lastname: Ellis
authors.forename: M J
authors.initials: MJ
authors.lastname: Evans
authors.forename: J E
authors.initials: JE
authors.lastname: Wells
authors.forename: R A
authors.initials: RA
authors.lastname: Donald
authors.forename: E A
authors.initials: EA
authors.lastname: Espiner
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D001127:Arginine Vasopressin / Q000097:blood*; D001794:Blood Pressure / Q000502:physiology; D003346:Corticotropin-Releasing Hormone / Q000097:blood*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D012964:Sodium / Q000097:blood
chemical_list: D007773:Lactates; D001127:Arginine Vasopressin; D019344:Lactic Acid; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D012964:Sodium