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Effects of Hypergravity and Food Intake on Gene Expression of Enzymes in the Liver of Periparturient Rats.    L. Lintault1, E. Zakrzewska1, R. Maple1, L. Baer2, A. Ronca3, C. Wade4, K. Plaut5. 1UVM, Burlington, Vermont, 2NASA-ARC, Moffett Field, CA, 3Wake Forest University School of Medicine, Winston-Salem, NC, 4USA ISR, Fort Sam Houston, TX, 5MSU, East Lansing, MI.

   Pregnant rats subjected to hypergravity (HG) have higher rates of glucose incorporation into lipids in the liver than both stationary control (SC) and pair-fed (PF) rats. Lactating HG and PF rats have lower rates of glucose incorporation into lipids in the liver than SC. To determine whether the effects of HG on liver lipid metabolism are due to reduced food intake, we analyzed gene expression of enzymes involved in lipid metabolism that respond to nutritional status: ATP citrate lyase (ACL), acetyl-CoA carboxylase (ACAC), fatty acid synthase (FAS), and lipoprotein lipase (LPL). Pregnant rats (gestation d 11) were centrifuged at 2.0-g (HG), kept at 1.0-g (SC), or kept at 1.0-g and fed to match the food intake of the HG rats (PF). Dams were removed on gestation d 21 (G21) or postpartum d 3 (P3), and livers were collected. RNA was extracted, reverse transcribed, and qRT-PCR performed. In G21 dams, gene expression was less in PF compared to SC and HG for ACAC (0.4, 1.0 and 1.1 for PF, SC and HG; p<0.01; SEM=0.2) and FAS (0.3, 1.3 and 2.2 for PF, SC and HG; p<0.05; SEM=0.5). Expression of ACL was 0.5, 1.1 and 2.1 for PF, SC and HG, with PF rats less than HG (p=0.05; SEM=0.4). LPL expression was not different among treatments. In P3 dams, gene expression of SC and HG was not different from PF, but HG was less than SC for ACL (0.8, 1.1 and 0.5 for PF, SC and HG; p<0.05; SEM=0.2) and FAS (1.0, 1.1 and 0.5 for PF, SC and HG; p<0.1; SEM=0.2). ACAC expression was not different among treatments. Expression of LPL was 0.6, 1.3 and 2.1 for PF, SC and HG, with PF rats less than HG (p<0.05; SEM=0.4). Gene expression of ACL, ACAC and FAS matches the trends in the metabolic data. The expression of LPL does not follow the same trends due to its role in lipolysis. Clearly, the changes observed in gene expression in the liver indicate that a reduction in food intake can not account for the changes observed in hypergravity. (Supported by NASA NCC2-1373 and NASA EPSCoR NCC5-581)