Signal crosstalk between estrogen and peroxisome proliferator-activated receptor alpha on adiposity.

Peroxisome proliferator-activated receptor alpha and estrogen are believed to be involved in metabolic changes leading to obesity. To test this relationship, we divided female wildtype and PPAR alpha-deficient mice fed on a high fat diet into the following groups: mock-operated, ovariectomized (OVX), and E(2)-treated. The visceral white adipose tissue and plasma cholesterol levels were increased significantly in wild type OVX and decreased in the E(2)-treated group, but interestingly not in PPAR alpha-deficient mice. The mRNA levels of lipoprotein lipase in adipose tissue were also increased in only wild type OVX and decreased significantly in E(2)-treated mice. These novel results suggest the possibility of signaling crosstalk between PPAR alpha and E2, causing obesity in vivo.