| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Department of Medical Physiology, Panum Institute, and 2 Danish Aerospace Medical Center of Research, Rigshospitalet, University of Copenhagen, DK-2200 Copenhagen; and 3 Department of Medical Biology, University of Southern Denmark, DK-5000 Odense, Denmark
Body fluid homeostasis was investigated during chronic bed rest (BR) and compared with that of acute supine conditions. The hypothesis was tested that 6° head-down BR leads to hypovolemia, which activates antinatriuretic mechanisms so that the renal responses to standardized saline loading are attenuated. Isotonic (20 ml/kg body wt) and hypertonic (2.5%, 7.2 ml/kg body wt) infusions were performed in eight subjects over 20 min following 7 and 10 days, respectively, of BR during constant sodium intake (200 meq/day). BR decreased body weight (83.0 ± 4.8 to 81.8 ± 4.4 kg) and increased plasma osmolality (285.9 ± 0.6 to 288.5 ± 0.9 mosmol/kgH2O, P < 0.05). Plasma ANG II doubled (4.2 ± 1.2 to 8.8 ± 1.8 pg/ml), whereas other endocrine variables decreased: plasma atrial natriuretic peptide (42 ± 3 to 24 ± 3 pg/ml), urinary urodilatin excretion rate (4.5 ± 0.3 to 3.2 ± 0.1 pg/min), and plasma vasopressin (1.7 ± 0.3 to 0.8 ± 0.2 pg/ml, P < 0.05). During BR, the natriuretic response to the isotonic saline infusion was augmented (39 ± 8 vs. 18 ± 6 meq sodium/350 min), whereas the response to hypertonic saline was unaltered (32 ± 8 vs. 29 ± 5 meq/350 min, P < 0.05). In conclusion, BR elicits antinatriuretic endocrine signals, but it does not attenuate the renal natriuretic response to saline stimuli in men; on the contrary, the response to isotonic saline is augmented.
vasopressin; atrial natriuretic factor; urodilatin; natriuresis; angiotensin II
This article has been cited by other articles:
|
|
 |
|
  D. H. J. Thijssen, G. A. Rongen, P. Smits, and M. T. E. Hopman Physical (in)activity and endothelium-derived constricting factors: overlooked adaptations J. Physiol., January 15, 2008; 586(2): 319 - 324. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. E. Lohmeier Neurohypophysial hormones Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2003; 285(4): R715 - R717. [Full Text] [PDF]
|
|
|
|
|
|
O. Skott Body sodium and volume homeostasis Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2003; 285(1): R14 - R18. [Full Text] [PDF]
|
|
|
|
 |
|
 P. J. Mueller and E. M. Hasser Enhanced sympathoinhibitory response to volume expansion in conscious hindlimb-unloaded rats J Appl Physiol, May 1, 2003; 94(5): 1806 - 1812. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. M. Stauss Baroreceptor reflex function Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2002; 283(2): R284 - R286. [Full Text] [PDF]
|
|
|
|
|
|
B. Pump, U. Talleruphuus, N. J. Christensen, J. Warberg, and P. Norsk Effects of supine, prone, and lateral positions on cardiovascular and renal variables in humans Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2002; 283(1): R174 - R180. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. J. Andersen, J. L. Andersen, B. Pump, and P. Bie Natriuresis induced by mild hypernatremia in humans Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2002; 282(6): R1754 - R1761. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. H. Bestle, N. V. Olsen, T. D. Poulsen, R. Roach, N. Fogh-Andersen, and P. Bie Prolonged hypobaric hypoxemia attenuates vasopressin secretion and renal response to osmostimulation in men J Appl Physiol, May 1, 2002; 92(5): 1911 - 1922. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
