Acute effects of head-down tilt and hypoxia on modulators of fluid homeostasis

P. A. Whitson, Nitza Cintron, R. A. Pietrzyk, P. Scotto, J. A. Loeppky

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

In an effort to understand the interaction between acute postural fluid shifts and hypoxia on hormonal regulation of fluid homeostasis, the authors measured the responses to head-down tilt with and without acute exposure to normobaric hypoxia. Plasma atrial natriuretic peptide (ANP), cyclic guanosine monophosphate (cGMP), cyclic adenosine monophosphate (cAMP), plasma aldosterone (ALD), and plasma renin activity (PRA) were measured in six healthy male volunteers who were exposed to a head-down tilt protocol during normoxia and hypoxia. The tilt protocol consisted of a 17° head-up phase (30 minutes), a 28° head-down phase (1 hour), and a 17° head-up recovery period (2 hours, with the last hour normoxic in both experiments). Altitude equivalent to 14,828 ft was simulated by having the subjects breathe an inspired gas mixture with 13.9% oxygen. The results indicate that the postural fluid redistribution associated with a 60-minute head-down tilt induces the release of ANP and cGMP during both hypoxia and normoxia. Hypoxia increased cGMP, cAMP, ALD, and PRA throughout the protocol and significantly potentiated the increase in cGMP during head-down tilt. Hypoxia had no overall effect on the release of ANP, but appeared to attenuate the increase with head-down tilt. This study describes the acute effects of hypoxia on the endocrine response during fluid redistribution and suggests that the magnitude, but not the direction, of these changes with posture is affected by hypoxia.

Original languageEnglish (US)
Pages (from-to)427-433
Number of pages7
JournalJournal of Clinical Pharmacology
Volume34
Issue number5
StatePublished - 1994
Externally publishedYes

Fingerprint

Head-Down Tilt
Homeostasis
Atrial Natriuretic Factor
Head
Cyclic GMP
Aldosterone
Renin
Fluid Shifts
Hypoxia
Posture
Healthy Volunteers
Gases
Oxygen

ASJC Scopus subject areas

  • Pharmacology (medical)
  • Pharmacology, Toxicology and Pharmaceutics(all)

Cite this

Whitson, P. A., Cintron, N., Pietrzyk, R. A., Scotto, P., & Loeppky, J. A. (1994). Acute effects of head-down tilt and hypoxia on modulators of fluid homeostasis. Journal of Clinical Pharmacology, 34(5), 427-433.

Acute effects of head-down tilt and hypoxia on modulators of fluid homeostasis. / Whitson, P. A.; Cintron, Nitza; Pietrzyk, R. A.; Scotto, P.; Loeppky, J. A.

In: Journal of Clinical Pharmacology, Vol. 34, No. 5, 1994, p. 427-433.

Research output: Contribution to journalArticle

Whitson, PA, Cintron, N, Pietrzyk, RA, Scotto, P & Loeppky, JA 1994, 'Acute effects of head-down tilt and hypoxia on modulators of fluid homeostasis', Journal of Clinical Pharmacology, vol. 34, no. 5, pp. 427-433.
Whitson, P. A. ; Cintron, Nitza ; Pietrzyk, R. A. ; Scotto, P. ; Loeppky, J. A. / Acute effects of head-down tilt and hypoxia on modulators of fluid homeostasis. In: Journal of Clinical Pharmacology. 1994 ; Vol. 34, No. 5. pp. 427-433.
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