Tucker BJ, Mendonca MM.
ASGSB Bull. 1992 Oct; 6: 64.
University of California San Diego, La Jolla.
Transition from a normal gravitational environment to that of microgravity results in decreased plasma (PV) and blood volume (BV). However the concurrent alterations in renal function, a major participant in volume homeostasis, have not been fully investigated. Male Wistar rats (n=7) were chronically cannulated in the femoral artery and vein, and the bladder. Two control measurements of extracellular fluid volume (ECF), glomerular filtration rate (GFR), and renal plasma flow (RPF) were obtained followed by tail suspending the rats in 25 degrees head-down tilt (HDT) in which these parameters were monitored for 30 days and for 7 days following HDT (P-HDT). PV and BV were performed in a separate group of rats utilizing the same protocol. GFR, RPF, and ECF increased in within 3 days of HDT (P<0.05) and, in most cases, remained at values greater than control to day 14 HDT. Following 14 days HDT, values for GFR, RPF, and ECF returned to values similar to control during the remainder of HDT. In P-HDT, GFR, RPF, and ECF returned to control values by day 3 P-HDT. However, BV and PV did not increase after 1 day HDT and decreased by day 7 HDT and remained decreased to 30 day HDT (P<0.05). CONCLUSIONS: GFR increased, most likely through increased RPF, responding to ECF expansion. However, PV and BV changes dissociated from ECF indicating alterations in normal fluid compartment homeostasis.
Publication Types:
Keywords:
- Animals
- Blood Volume
- Glomerular Filtration Rate
- Head
- Head-Down Tilt
- Male
- Rats
- Rats, Inbred Strains
- Rats, Sprague-Dawley
- Rats, Wistar
- Renal Plasma Flow
- NASA Discipline Cardiopulmonary
- NASA Discipline Number 14-10
- NASA Program Space Physiology and Countermeasures
- Non-NASA Center
Other ID:
UI: 102212523
From Meeting Abstracts