GASTRIC MICROCIRCULATORY CHANGES OF PORTAL-HYPERTENSIVE RATS CAN BE ATTENUATED BY LONG-TERM ESTROGEN-PROGESTAGEN TREATMENT

It has been suggested that estrogen-progestagen therapy may be useful in preventing bleeding from gastric angiodysplasia, a vascular lesion similar to that described in portal-hypertensive gastropathy. In this study we assessed the effects of estrogen-progestagen therapy on gastr ic microcirculation and systemic and splanchnic hemodynamics in portal -hypertensive and sham-operated rats. One week after the surgical proc edure (partial portal vein ligation or sham surgery), animals were giv en an intramuscular injection of a slow-release preparation of estroge n-progestagen or its vehicle. Two weeks later, gastric mucosal blood h ow was measured by means of hydrogen gas clearance, a morphometrical a nalysis of gastric mucosal blood vessels was performed and systemic an d splanchnic hemodynamics were evaluated with a radiolabeled-microsphe res technique. In portal-hypertensive rats, estrogen-progestagen thera py induced a significant reduction in gastric mucosal blood how, numbe r of blood vessels and relative area of vessels. Similar changes, alth ough of lesser magnitude, were achieved with estrogen or progestagen g iven separately and with the low dose of combined estrogen-progestagen . Estrogen-progestagen treatment also induced significant reductions i n portal pressure and porto-collateral resistance without changing sys temic or splanchnic hemodynamics. In contrast, estrogen-progestagen tr eatment did not induce changes in any of the parameters studied in sha m-operated rats. We conclude that long-term estrogen progestagen thera py reduces the gastric hyperemia, increased mucosal vessel density and portal pressure in portal-hypertensive rats.