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EXPERIMENT INFORMATION

Nutritional Modulation of Pancreatic Endocrine Function in Microgravity (NCC958NPFR00204)
Principal Investigator
Research Area:
Metabolism and nutrition
Species Studied
Scientific Name: Homo sapiens Species: Human

Description
OBJECTIVES:
Ground-based and in-flight investigations illustrate changes in insulin, glucose, and amino acid metabolism in space flight. These observations may relate to altered pancreatic endocrine function, which is insufficient to meet the needs of microgravity-induced insulin resistance, and altered amino acid metabolism. The changes observed include decreased glucose tolerance, increased circulating insulin, and increased reliance upon glucose in muscles. The metabolic milieu resembles an insulin resistant syndrome, accompanied by a compensatory increase in pancreatic insulin secretion. However, the increase in insulin secretion is insufficient to ameliorate muscle atrophy. The increased insulin secretion is well correlated to muscle atrophy in space flight. The influence of these changes upon the loss of muscle mass and general endocrine metabolic state are not well established, however. Countermeasures which could modulate insulin and glucagon secretion in a compensatory manner to overcome insulin resistance and promote amino acid uptake by peripheral musculature might decrease muscle atrophy and reduce injury following re-adaptation to unit gravity.

It is hypothesized that human pancreatic islets of Langerhans have an increased requirement for amino acids in microgravity. It is also hypothesized, that supplementation with specific additional amino acids will augment, enhance and normalize insulin secretion, when space flight paradigm stressors known to decrease insulin secretion, are applied. The specific aims in this study are to:

1) assess the effect of a microgravity model cell culture on basal amino acid requirements and endocrine secretory function in human islets of Langerhans, and
2) determine human islet endocrine function while testing amino acid countermeasures in the microgravity model.

RESULTS:
It is anticipated that these studies will further refine our understanding of human pancreatic amino acid requirements and endocrine regulation: phenomenon which may be limiting to extended-duration space flight missions. These studies will test countermeasures to augment pancreatic endocrine function, while considering both insulin and glucagon production in a way that will involve supplementation of diet with additional amino acids. These measures are ultimately aimed at improving space flight induced muscle atrophy, and ameliorating current re-adaptation constraints.

Data Information
Data Availability
Archive is complete. No data sets are available for this experiment. Please Contact LSDA if you know of available data for this investigation.

Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Ground 05/01/2009 In Progress

Additional Information
Managing NASA Center
National Space Biomedical Research Institute (NSBRI)
Responsible NASA Representative
Johnson Space Center LSDA Office
Project Manager: Pamela A. Bieri
Institutional Support
National Aeronautics and Space Administration (NASA)
Proposal Date
07/01/2001
Proposal Source
NSBRI