title: Impaired PI3 K Akt expression in liver and skeletal muscle of ovariectomized rats.
abstract: It is well established that estrogen deficiency is strongly linked to the development of insulin resistance (IR), but the mechanism is still unclear. Since IR is characterized by a marked reduction in insulin-stimulated PI3 K-mediated activation of Akt in liver and skeletal muscle, we hypothesized that ovariectomized rats (OVX) would exhibit reductions in the expression of proteins in PI3 K signaling pathway, including PI3 K and Akt. As hypothesized, after observing for 12 weeks, compared with the SHAM rats, ovariectomy led to decreased plasma estrogen level and increased HOMA-IR index; in addition, ovariectomy also caused decreased PI3 K and Akt expression levels in the liver and skeletal muscle. Interestingly, the expression patterns differed in tissue-dependent fashion: Akt1 was only found reduction in liver, whereas Akt2 decreased in muscle; these changes can be reversed by estrogen supplement (OVXE). In conclusion, data demonstrate that estrogen withdrawals may cause IR at least in part by impaired PI3 K/Akt signaling proteins in liver and skeletal muscle, and Akt1 and Akt2 might be tissue-specific expressions.
authors: Department of Endocrinology, The Third Hospital of Hebei Medical University, Shijiazhuang, 050051, China, wangyan0208@yahoo.cn.
authors: Yan
authors: Y
authors: Wang
authors: Baoxin
authors: B
authors: Li
authors: Wei
authors: W
authors: Zhang
authors: Yan
authors: Y
authors: Liu
authors: Peng
authors: P
authors: Xue
authors: Jianxia
authors: J
authors: Ma
authors: Yukun
authors: Y
authors: Li
mesh_terms: D000818:Animals; D004967:Estrogens / Q000097:blood / Q000494:pharmacology; D005260:Female; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D010052:Ovariectomy; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000502:physiology
chemical_list: D004967:Estrogens; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt
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