Expression and activation of Akt/protein kinase B in sexually immature and mature rat uterus.
This study investigated the expression and activation of Akt/PKB in developing and adult rat uterus. Expression of Akt was observed in uteri from adult ovariectomized and 7-35-day-old rats and no changes were observed in response to in vivo estradiol treatment (1-100 microg/100g b.w.). To examine the mechanisms of PKB/Akt activation, phosphorylation at Thr(308) and Ser(473) regulatory sites were studied in uteri. Akt was constitutively phosphorylated on Ser(473) residue in the untreated, control uteri, while phosphorylation of Thr(308) was observed only after estradiol 17beta (E2) treatment. The effects of E2 treatment were age dependent, no response was induced in 11-day-old uteri, while in 28 days and older rats the activation of Akt at both regulatory sites, Ser(473) and Thr(308), increased, the first response was detected 2h after treatment, reaching the highest rate at 6h. The rate of phosphorylation was stronger at Ser(473) residue. The results suggest that the regulation of Akt activation at two regulatory sites in rat uteri are different, phosphorylation of Thr(308) seems to be entirely estrogen dependent, while the phosphorylation of Ser(473) is regulated by other factors as well as estrogen.
Lengyel
Ferenc
F
Institute of Physiology, Pécs University Medical School, Szigeti út 12, Pécs H7624, Hungary. ferenc.lengyel@aok.pte.hu
Vértes
Zsuzsanna
Z
Kovács
Kálmán A
KA
Környei
József L
JL
Sumegi
Balázs
B
Vértes
Marietta
M
D017677:Age Distribution; D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects*; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D018507:Gene Expression Regulation, Developmental; D010052:Ovariectomy; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D017208:Rats, Wistar; D012694:Serine / Q000737:chemistry; D013912:Threonine / Q000737:chemistry; D014599:Uterus / Q000201:enzymology* / Q000254:growth & development*
D011518:Proto-Oncogene Proteins; D013912:Threonine; D012694:Serine; D004958:Estradiol; C494920:Akt1 protein, rat; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt