Voluntary Corn Oil Ingestion Increases Energy Expenditure and Interscapular UCP1 Expression Through the Sympathetic Nerve in C57BL/6 Mice

Abstract

Scope: Previously, it has been found that corn oil ingestion activates both the gustatory system and brain reward system, stimulating motivation for eating. In the present study, the effect of voluntary corn oil ingestion on body weight gain and energy metabolism in mice is investigated.

Methods and results: Voluntary corn oil ingestion with normal chow feeding does not lead to higher body weight than that of only the chow-fed control group. Mice that ingested corn oil have a higher total caloric intake and energy expenditure than did mice in the control group. Further, voluntary corn oil ingestion significantly upregulates Ucp1 mRNA and protein in interscapular brown adipose tissue (IBAT). Finally, the sympathetic nerve connected to IBAT was surgically transacted, then the body weight is measured for 8 weeks. IBAT sympathetic nerve transection surgery does not affect the body weight gain and food intake; however, when mice ingested corn oil, it induces significant body weight gain without changing the total caloric intake. IBAT sympathetic nerve transection surgery significantly suppresses UCP1 upregulation by corn oil ingestion.

Conclusion: The present data suggest that corn oil ingestion activates IBAT through the sympathetic nerve, upregulating UCP1 expression and increasing energy expenditure.

Keywords: UCP1; brown adipose tissue; dietary fat; energy expenditure; sympathetic nerve.