Peroxisome proliferator-activated receptor gamma1 (PPAR-gamma1) as a major PPAR in a tissue in which estrogen induces peroxisome proliferation.

Estradiol administration induces peroxisome proliferation and the production of 3-hydroxy fatty acid pheromones in the uropygial glands of the duck, but not in the goose gland, which does not produce such pheromones. We isolated a peroxisome proliferator-activated receptor (PPAR)gamma1 cDNA from a duck uropygial gland cDNA library. Northern blots revealed two transcripts, PPAR gamma1 and gamma2, and showed that PPAR gamma was expressed at higher levels than PPAR alpha in the uropygial gland of the duck. Although PPAR gamma2 was expressed in both duck and goose uropygial gland, PPAR gamma1 was expressed only in the duck gland, which responds to estrogen by peroxisome proliferation. In NIH 3T3 transfected cells, PPAR gamma1 was activated by peroxisome proliferators such as Wy-14643, clofibric acid and Ly-171883 causing induction of the target marker gene. By cotransfection with a plasmid containing alpha-cis-retinoic acid receptor RXR alpha, the induction increased up to 9-fold. These results suggest that PPAR gamma1 may be involved in peroxisome proliferation while PPAR gamma2 may be involved in lipid metabolism.