Chronic 17beta-estradiol treatment improves skeletal muscle insulin signaling pathway components in insulin resistance associated with aging.
Insulin resistance is a common feature of aging in both humans and rats. In the case of females, it seems to be related to loss of gonadal function, due mainly due to a decrease in plasma estrogen levels. Several causes have been postulated for this insulin resistance, among them changes in several steps of the insulin pathway. In view of these findings, the purpose of the present study was to examine the role of chronic 17beta-estradiol treatment on insulin sensitivity during the aging process, and its effects on levels of the insulin-sensitive glucose transporter Glut4 (both total and plasma membrane localized), the interaction between p85alpha subunit of PI3-k and IRS-1, Tyr- and Ser-612 phosphorylation of IRS-1 levels, and Ser-473 phosphorylation of Akt. The present findings indicate that 17beta-estradiol treatment is able to minimize the deleterious effect of aging on insulin sensitivity, at least at the level of plasma membrane localized Glut4. Nevertheless further research is needed to determine this conclusively.
Moreno
M
M
Department of Functional Biology, University of Oviedo, Oviedo, Spain.
Ordoñez
P
P
Alonso
A
A
Díaz
F
F
Tolivia
J
J
González
C
C
D000375:Aging / Q000187:drug effects / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D004958:Estradiol / Q000097:blood / Q000494:pharmacology*; D005260:Female; D005947:Glucose / Q000378:metabolism; D015309:Glucose Clamp Technique; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D047468:Immunoprecipitation; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins / Q000378:metabolism; D007333:Insulin Resistance; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism*; D010052:Ovariectomy; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors
D004958:Estradiol; D005947:Glucose; D051275:Glucose Transporter Type 4; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; C526296:Irs1 protein, rat