Effects of endogenous ovarian estrogen versus exogenous estrogen replacement on blood flow and ERβα and ERβ levels in the bladder.
OBJECTIVE
Determine the effect of endogenous estrogen versus estrogen replacement therapy (ERT) on bladder blood flow (BBF) and estrogen receptors (ERs).


METHODS
BBF was determined with radiolabeled microspheres in luteal, follicular, pregnant, oophorectomized (Ovx) sheep, and Ovx sheep with ERT. Estrogen receptors (ERalpha, ERbeta) were quantified using Western blot analysis.


RESULTS
Compared to luteal and follicular ewes, BBF was reduced in pregnancy and following oophorectomy. Estrogen replacement therapy in Ovx sheep restored BBF to luteal levels. Estrogen receptor alpha predominated, whereas ERbeta was not detectable. Estrogen receptor-alpha levels were unaffected by the ovarian cycle and increased in pregnancy, as well as in Ovx sheep with and without chronic ERT.


CONCLUSIONS
The combination of diminished BBF and elevated ERalpha levels in both pregnant and Ovx sheep suggests an inverse relationship between BBF and ERalpha in the bladder. Although chronic ERT in Ovx sheep restored BBF, it did not restore ERalpha back to luteal levels.
Ablove
Tova S
TS
Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Perinatal Research Laboratories, Madison, Wisconsin 53715, USA.
Austin
Jason L
JL
Phernetton
Terry M
TM
Magness
Ronald R
RR
D000818:Animals; D047628:Estrogen Receptor alpha / Q000378:metabolism / Q000502:physiology*; D047629:Estrogen Receptor beta / Q000378:metabolism / Q000502:physiology*; D015914:Estrogen Replacement Therapy / Q000379:methods; D004967:Estrogens / Q000494:pharmacology* / Q000502:physiology*; D005260:Female; D010053:Ovary / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D012756:Sheep; D001743:Urinary Bladder / Q000098:blood supply* / Q000187:drug effects / Q000378:metabolism*
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens