Medroxyprogesterone acetate attenuates estrogen-induced nitric oxide production in human umbilical vein endothelial cells.
We report the novel observation that medroxyprogesterone acetate (MPA) attenuates the induction by 17beta estradiol (E2) of both nitric oxide (NO) production and endothelial nitric oxide synthase (eNOS) activity in human umbilical vein endothelial cells. Although MPA had no effect on basal NO production or basal eNOS phosphorylation or activity, it attenuated the E2-induced NO production and eNOS phosphorylation and activity. Moreover, we examined the mechanism by which MPA attenuated the E2-induced NO production and eNOS phosphorylation. MPA attenuated the E2-induced phosphorylation of Akt, a kinase that phosphorylates eNOS. Treatment with pure progesterone receptor (PR) antagonist RU486 completely abolished the inhibitory effect of MPA on E2-induced Akt phosphorylation and eNOS phosphorylation. In addition, the effects of actinomycin D were tested to rule out the influence of genomic events mediated by nuclear PRs. Actinomycin D did not affect the inhibitory effect of MPA on E2-induced Akt phosphorylation. Furthermore, the potential roles of PRA and PRB were evaluated. In COS cells transfected with either PRA or PRB, MPA attenuated E2-induced Akt phosphorylation. These results indicate that MPA attenuated E2-induced NO production via an Akt cascade through PRA or PRB in a non-genomic manner.
Department of Obstetrics and Gynecology, Dokkyo University School of Medicine, 880, Kitakobayashi, Mibumachi, Shimotuga, Tochigi 321-0293, Japan.
Akira
A
Oishi
Masahide
M
Ohmichi
Kazuhiro
K
Takahashi
Toshifumi
T
Takahashi
Akiko
A
Mori-Abe
Jun
J
Kawagoe
Reiko
R
Otsu
Yoshiko
Y
Mochizuki
Noriyuki
N
Inaba
Hirohisa
H
Kurachi
D000818:Animals; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003271:Contraceptive Agents, Female; D003609:Dactinomycin / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D006727:Hormone Antagonists / Q000494:pharmacology; D006801:Humans; D017258:Medroxyprogesterone Acetate / Q000494:pharmacology*; D015735:Mifepristone / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III; D019384:Nucleic Acid Synthesis Inhibitors / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D011980:Receptors, Progesterone / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology / Q000187:drug effects*
D003271:Contraceptive Agents, Female; D006727:Hormone Antagonists; D019384:Nucleic Acid Synthesis Inhibitors; D011518:Proto-Oncogene Proteins; D011980:Receptors, Progesterone; D003609:Dactinomycin; D009569:Nitric Oxide; D015735:Mifepristone; D004958:Estradiol; D017258:Medroxyprogesterone Acetate; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt