Regulation of Adipose Tissue Metabolism by Dietary Fat Prior to the Onset of Obesity During Fasting and After Refeeding

Abstract

It is not well known how the adipose tissue (AT) is affected by the dietary fat (amount and type) prior to the onset of obesity during fasting and short‐term refeeding (30–120 min). Thus, we studied rats fed 7 or 21% coconut (CO, saturated), safflower (SF, monounsaturated) or soybean (SB, polyunsaturated) oil for 21 d. Our data showed that the storage of triglycerides (TG) in AT after refeeding was faster in animals fed 21% dietary fat, particularly CO, however, after 2 h of refeeding, the amount of TG stored was similar among groups, which is in accordance to the size of adipocytes. In addition, after meal ingestion, lipolysis in animals fed 7% dietary fat was totally repressed, independent of the type of fat, whereas in rats fed 21% dietary fat, lipolysis was partially abolished and AT showed a lower esterification index. The expression of esterification of fatty acids (FA) and lipolytic genes followed a similar trend of re‐esterification and lipolysis. The composition of serum free FA in fasting was only dependent by the type of fat; saturated FA content was higher in animals fed CO and lower in animals fed SB, whereas polyunsaturated FA content had the opposite pattern. The secretion of adipokines (leptin, adiponectin, RBP‐4, visfatin and resistin) did not change in fasting among groups; however, after reefeding significant differences were dependent upon the amount and/or type of fat. (Conacyt grant to ADV No. 0154126)