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Responses of plasma proenkephalin peptide F in rats following 14 days of spaceflight


Kraemer, WJ and Gordon, SE and Koziris, LP and Jemiolo, B and Bush, JA and Staron, RS and Volek, JS and French, DN and Sharman, MJ and Mastro, A and Hymer, WC, Responses of plasma proenkephalin peptide F in rats following 14 days of spaceflight, Aviation, Space, and Environmental Medicine, 2004 Feb, (75(2)) pp. 114-7. ISSN 0095-6562 (2004) [Refereed Article]


INTRODUCTION: . Proenkephalin peptide F [107-140] is related to the enhancement of immune function, while microgravity has been shown to cause immuno-suppression. We investigated the physiological response of proenkephalin peptide F to microgravity. METHODS: There were 12 Fischer 344 female rats, ovariectomized at 10.5 wk of age, used to determine plasma concentrations of peptide F in response to a 14-d flight aboard the Columbia Space Shuttle mission STS-62. There were 36 other such rats that served as ground-based controls to separate the effects of microgravity from those of thermal stress, flight stress, and crowded habitats. Control groups of 12 rats each were kept under the following conditions: 1) 22 degrees C vivarium, 2) 28 degrees C vivarium, and 3) variable (Var) to mimic flight. The flight and control groups were housed in animal enclosure modules 21 d prior to flight and for the duration of the study. The rats were sacrificed within 4-5 h after landing, at which time blood samples were obtained. RESULTS: Body weights were obtained prior to sacrifice; mean values were flight, 199 g; 22 degrees C, 193 g; 28 degrees C, 192 g; and Var, 194 g. The flight group produced a significantly greater (p < or = 0.05) level of plasma peptide F (0.056 pmol x ml(-1)) compared with the controls (0.016, 0.022, and 0.016 pmol x ml(-1) for 22 degrees C, 28 degrees C, and Var, respectively). Flight animals demonstrated higher corticosterone concentrations and reduced T and B cell splenocyte counts than controls. CONCLUSIONS: These data indicate that the increases in proenkephalin peptide F observed with exposure to microgravity may present an adrenal-medullary response to cope with the decreased immune function and increased stress experienced during spaceflight and landing.

Item Details

Item Type:Refereed Article
Research Division:Health Sciences
Research Group:Sports science and exercise
Research Field:Biomechanics
Objective Division:Health
Objective Group:Evaluation of health and support services
Objective Field:Evaluation of health and support services not elsewhere classified
UTAS Author:Sharman, MJ (Dr Matt Sharman)
ID Code:79027
Year Published:2004
Deposited By:Health Sciences A
Deposited On:2012-08-14
Last Modified:2012-08-14

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