Submission Number: HEI-4-35-22

Abstract Number: 399

EFFECTS OF PROLONGED PROGESTERONE, ESTROGEN, AND COMBINATION TREATMENT ON UBF REDISTRIBUTION AND TISSUE SPECIFIC eNOS EXPRESSION IN OVINE UTERINE MICROVASCULATURE.

Heidi L Rupnow ¹, Terrance M Phernetton ¹, ML Modrick ¹, Cynthia E Shaw ¹, Ian M Bird ¹ and Ronald R Magness* ^1,2

Perinatal Res. Labs., Depts. Ob/Gyn, Meriter Hospital, Madison, WI ¹
Department of Animal Sciences, University of Wisconsin, Madison, WI ²

Abstract:
UBF and uterine artery eNOS expression are greatest during the follicular versus luteal phase of the cycle. Treatment with Estradiol-17 (E₂B) increases UBF and uterine artery eNOS expression. Purpose: To evaluate the effects of Progesterone (P₄ ) E₂B on UBF redistribution to the Endometrium (Endo), Myometrium (Myo), and Caruncles (Car) in relation to eNOS expression in the regional uterine microvasculature. Methods: Nonpregnant ovariectomized sheep received either Vehicle (V; n=9), P₄ (0.9g CIDRS vaginal implants; n=7), E₂B(5g/kg bolus followed by 6g/kg/d; n=9), or P₄ + E₂B(n=7) with radioactive microspheres injected into the left ventricle to determine UBF distribution at control and 10 days. Other nonpregnant ovariectomized sheep received the same treatments for 10 days (V n=9; P₄ n=9; E₂B n=9; P₄ + E₂B n=7) and Endo, Myo, and Car microvessels were procured; eNOS protein expression was quantified by Western analysis and scanning densitometry. Results: Prolonged E₂B and P₄ + E₂B increased (P<0.05) UBF (ml/min) to the Endo, Myo, and Car while P₄ alone had no effect vs. V. With E₂B the percent of total UBF was significantly increased in the Myo and significantly decreased in the Car. P₄ alone increased UBF redistribution to the Endo and Car, but in combination with E₂B they decreased distribution to the Myo. E₂B alone and P₄ + E₂B (P<0.05) increased eNOS expression in Myo microvessels (V = 10026%, E₂B = 28279%, P₄ + E₂B = 23557% of V). The exogenous steroid-induced increase in eNOS levels was specific to the Myo since neither Car nor Endo eNOS expression was altered. Conclusion: E₂B redistributed total UBF to the Myo, while E₂B and P₄ + E₂B increased eNOS expression in Myo microvessels. There was no effect of hormone treatment on eNOS expression in Endo and Car microvessels, however P₄ was able to increase blood flow redistribution to these regions. Support: NIH HL49210; HD33255; HL56753; HL56702.

Keywords: UBF, eNOS

This abstract is being presented at: 8:00 AM in session:
Uterus/Oviduct I