title: Hormonal and renal responses to water drinking in moderately trained and untrained humans.
abstract: Endurance exercise training alters the regulation of body fluids. To investigate specifics of these alterations, hormonal, electrolyte, and renal responses to water ingestion (1% of lean body wt) were studied in six moderately trained (T) and 6 untrained (UT) male subjects. No differences between groups for base-line hormonal, electrolyte, or renal measurements were found. After water ingestion, atrial natriuretic factor remained unaltered in both groups. Predrink plasma antidiuretic hormone (ADH) levels of 0.51 +/- (SE) 0.19 (UT) and 0.47 +/- 0.07 microU/ml (T) remained unchanged in the T group but were reduced from min 9 through 90 in the UT group. At 30 min postdrink, UT subjects had lower ADH values than T subjects (0.18 +/- 0.02 vs. 0.33 +/- 0.05 microU/ml), while plasma osmolality was similarly reduced by approximately 3 mosmol/kg in both groups. Urine flow rates increased in both groups from similar values of 0.85 +/- 0.24 (UT) and 0.67 +/- 0.11 ml/min (T) to peak flows of 4.6 +/- 1.6 for UT and 2.7 +/- 1.1 ml/min (T) to peak T, P less than or equal to 0.05) at 60 min postdrink. Urine osmolality was reduced from similar values of 809.1 +/- 62.1 and 867.0 +/- 56.1 mosmol/kg to values of 248.8 +/- 87.6 and 469 +/- 146.1 mosmol/kg for UT and T, respectively (UT vs. T, P less than 0.05), at 60 min. Reduced ADH before reductions in plasma osmolality in the UT but not the T subjects suggests that T subjects have a reduced oropharyngeal inhibition of ADH.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Clinical Investigation, Tripler Army Medical Center, Honolulu, Hawaii 96859-5000.
authors.forename: B J
authors.initials: BJ
authors.lastname: Freund
authors.forename: J R
authors.initials: JR
authors.lastname: Claybaugh
authors.forename: G M
authors.initials: GM
authors.lastname: Hashiro
authors.forename: M S
authors.initials: MS
authors.lastname: Dice
mesh_terms: D000328:Adult; D000450:Aldosterone / Q000097:blood; D004231:Diuresis; D004326:Drinking; D006728:Hormones / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000502:physiology*; D008297:Male; D009994:Osmolar Concentration; D010806:Physical Education and Training; D010807:Physical Endurance; D011188:Potassium / Q000097:blood; D012964:Sodium / Q000097:blood
chemical_list: D006728:Hormones; D000450:Aldosterone; D012964:Sodium; D011188:Potassium