Glucose Transporter 4 (GLUT4) mRNA Abundance in the Adipose Tissue and Skeletal-Muscle Tissue of Ovariectomized Rats Treated with 17β-Estradiol or Progesterone

Abstract
To investigate the effects of 17 beta-estradiol and progesterone on the expression of glucose transporter 4 (GLUT4) in the adipose tissue and skeletal-muscle tissue of ovariectomized rats. Female Sprague-Dawley rats (n = 63) received a daily subcutaneous injection of 10 micrograms, 50 micrograms, or 250 micrograms of 17 beta-estradiol (Group E) or of 1 mg, 5 mg or 25 mg of progesterone (Group P) for 3 days, 7 days, or 10 days (n = 3, at each dose). The expression of GLUT4 mRNA was assessed by performing ribonuclease protection assays. The levels of GLUT4 mRNA in adipose tissue was significantly reduced by treatment with estradiol, 50 micrograms or 250 micrograms, relative to findings in control rats (p < 0.01). No such reductions were seen regarding the progesterone treatment. The level of GLUT4 mRNA in skeletal-muscle tissue did not change, regardless of treatment. In ovariectomized rats, higher than physiologic dosages of 17 beta-estradiol can suppress the expression of GLUT4 mRNA in adipose tissue.