Meeting Abstract
To support the high energetic demands of reproduction, female mammals display plasticity in many physiological processes, such as the lipid transport system. Lipids function as a substrate for supporting the female’s energy demands and as a vital nutrient in milk. We hypothesized that key proteins which support lipid transport and mobilization will increase in level during pregnancy and lactation, but drop back to non-reproductive levels shortly after reproduction has ended. We characterized changes in pathways supporting fatty acid transport inside the liver, a key site of lipid storage and synthesis, and lipid delivery to tissues in reproductive Sprague-Dawley rats during late pregnancy, peak-lactation, 1-week post-lactation and in age-matched non-reproductive rats. Liver-type cytoplasmic fat transporter (L-FABP), plasma membrane fat transporter, fatty acid translocase (FAT/CD36) levels in the liver, and free fatty acid transporter albumin and triglyceride transporter (very low density lipoprotein) levels in blood serum were quantified. We found that albumin levels in serum was greater during pregnancy than non-reproductive rats. Lactating and post-lactating rats had significantly higher levels of L-FABP than their controls. Post-lactation rats had higher levels of FAT/CD36 than all other groups. These results indicate that fat transport capacities inside liver cells and in blood are elevated during lactation and pregnancy respectively. However, fat transport capacities were still higher than non-reproductive rats one week after lactation, which could be due to regression of the mammary glands after lactation and/or the mobilization of lipids stored during reproduction.
