Seadragon VI: a 7-day dry saturation dive at 31 ATA. VI. Hyperbaria enhances renin but eliminates ADH responses to head-up tilt

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Seadragon VI: a 7-day dry saturation dive at 31 ATA. VI. Hyperbaria enhances renin but eliminates ADH responses to head-up tilt

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Title: Seadragon VI: a 7-day dry saturation dive at 31 ATA. VI. Hyperbaria enhances renin but eliminates ADH responses to head-up tilt
Author: Matsui, N; Claybaugh, JR; Tamura, Y; Seo, H; Murata, Y; Shiraki, K; Nakayama, H; Lin, YC; Hong, SK
Abstract: Three male subjects were passively tilted from a supine to a 90 degree head-up standing position on 2 d each at 1 and 31 ATA, then on 1 d of the postdive period. On each day the subjects were tilted once in the morning (0800-1000) and once in the evening (2000-2200). Before each tilt experiment, the subjects were first intravenously cannulated for blood sampling, then assumed the supine position. A blood sample was taken after 10 min in the supine position, and another sample was taken after 15 min of motionless, supported standing. The plasma was analyzed for antidiuretic hormone (ADH), plasma renin activity (PRA), plasma cortisol, and aldosterone. ADH, PRA, and cortisol were significantly increased by tilt, but the responses varied with time of day or atmospheric pressure. Cortisol increased only in the morning tilt (P less than 0.005) and was not affected by pressure. At 1 ATA, PRA was elevated in the morning tilt experiment (P less than 0.005) and not the evening tilt, but the overall response to tilt was greater at 31 ATA than at 1 ATA (P less than 0.005). The ADH response to tilt (P less than 0.025) was unaffected by time of day, but was eliminated at 31 ATA. The basal levels of ADH were also lower at 31 ATA (P less than 0.005). The mechanism of these responses remains unclear, but the eliminated postural stimulation of ADH may account for the eliminated circadian excretory pattern of the hormones. The altered responses to body fluid shifts possibly contribute to the increased aldosterone and decreased ADH frequently observed at hyperbaria.
Description: Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org )
URI: PMID: 3314056
http://archive.rubicon-foundation.org/2454
Date: 1987

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  • Undersea Biomedical Research Journal
    The Undersea Baromedical Research journal was published by the Undersea Medical Society, Inc. (now the Undersea and Hyperbaric Medical Society) quarterly from 1974 to 1992 when the name changed to the Undersea and Hyperbaric Medicine Journal.

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