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This Article Full Text Full Text (PDF) All Versions of this Article: 67/6/1681    most recent biolreprod.102.007252v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tou, J. Articles by Wade, C. Search for Related Content PubMed PubMed Citation Articles by Tou, J. Articles by Wade, C. Agricola Articles by Tou, J. Articles by Wade, C.

Models to Study Gravitational Biology of Mammalian Reproduction¹

^a Lockheed Martin Sciences and Engineering ^b Life Science Division, NASA Ames Research Center, Moffett Field, California 94035

Mammalian reproduction evolved within Earth's 1-g gravitational field. As we move closer to the reality of space habitation, there is growing scientific interest in how different gravitational states influence reproduction in mammals. Habitation of space and extended spaceflight missions require prolonged exposure to decreased gravity (hypogravity, i.e., weightlessness). Lift-off and re-entry of the spacecraft are associated with exposure to increased gravity (hypergravity). Existing data suggest that spaceflight is associated with a constellation of changes in reproductive physiology and function. However, limited spaceflight opportunities and confounding effects of various nongravitational factors associated with spaceflight (i.e., radiation, stress) have led to the development of ground-based models for studying the effects of altered gravity on biological systems. Human bed rest and rodent hindlimb unloading paradigms are used to study exposure to hypogravity. Centrifugation is used to study hypergravity. Here, we review the results of spaceflight and ground-based models of altered gravity on reproductive physiology. Studies utilizing ground-based models that simulate hyper- and hypogravity have produced reproductive results similar to those obtained from spaceflight and are contributing new information on biological responses across the gravity continuum, thereby confirming the appropriateness of these models for studying reproductive responses to altered gravity and the underlying mechanisms of these responses. Together, these unique tools are yielding new insights into the gravitational biology of reproduction in mammals.

¹ This research was supported by NASA grants 121-10-40, 121-10-50, and 121-40-10 and NIH grant 46485 (to C.W.).

² Correspondence: Charles E. Wade, Life Science Division, MS 239-11, NASA Ames Research Center, Moffett Field, CA 94035. FAX: 650 604 3954; cwade{at}mail.arc.nasa.gov

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