昇圧物質に対する昇圧反応性に及ぼす性ステロイドホルモンの影響について
スポンサーリンク
概要
- 論文の詳細を見る
Vascular refractoriness to infused angiotensin II (A II) characterizes normal human pregnancy. To investigate whether this refractoriness is related to the increased blood levels of steroid hormones during pregnancy, effects of estradiol 17-β(E2) and progesterone (P) on the pressor responsiveness to A II and norepinephrine (NE) were studied. After the preliminary experiments in which the pressor responsiveness to injected A II and NE were studied in instrumented nonpregnant and near-term pregnant dogs, dose-response curves describing the pressor response (ΔBP) were determined in oophorectomized dogs (n=20) before and after infusions of E2 or P.Under nembutal anesthesia, indwelling polyvinyl catheters were inplanted in left femoral artery to the level of the bifurcation of the abdominal aorta and right cubital vein. Mean arterial pressure and heart rate were monitored with interpolated pressure transducers and the signals were electronically integrated and recorded on a one-channel recorder. The venous catheter was used for the infusions of pressor substances or hormones.In the pregnant animals (n=5), the pressor response at every doses of A II (0.005, 0.025, 0.05, 0.075and 0.1μg/kg) and NE (0.6, 1.3, 2.5, 5.0 and 7.5μg/kg) was significantly less than that observed for nonpregnant dogs (n=5). In the pregnant animals the pressor response to A II fell to 55.7% of the response seen in the nonpregnant animals at the dose of 0.025μg/kg, and 62.5% of control at a dose of 0.1μg/kg. The pressor response to NE also fell to 70.4% and 84.8% of controls at the doses of 1.3μg/kg and 7.5μg/kg respectively in the pregnant animals, although the falls were not so remarkable as were seen in the response to A II. This implies that the pregnant dog develops vascular refractoriness to infused A II in much the same way as the human. Thus, it appears likely that the instrumented dog can serve as an animal model for studies of the mechanisms responsible for the development of vascular refractoriness to A II.On the 4th day after castration, response of mean arterial pressure to systemic infusions of A II (0.05, 0.1, 0.25 and 0.5μg/kg.min) or NE (0.5, 1, 2.5, 5.0μg/kg.min) was investigated before and after infusions of E2 (17μg/min) or P (42μg/min) for 90 minutes. E2 infusion lessened the pressor response to A II in the oophorectomized nonpregnant animals, e.g. at an infusion rate of 0.25μg/kg.min, theΔBP was 29.8±2.4mmHg (means±SE) before E2 infusion and 24.3±2.8mmHg afterwards (p<0.05), and at an infusion rate of 0.5μg/kg.min, theΔBP was 52.6±7.4mmHg before E2 infusion and 38.2±2.7mmHg afterwards (p<0.05). Thus, the E2 infusion in oophorectomized dogs results in a shift to the left of the dose-response curve describing the pressor effects of A II. A similar effect was seen in the pressor response to NE, e.g.
- 近畿産科婦人科学会の論文
近畿産科婦人科学会 | 論文
- 当院における卵巣粘液性腺癌の治療経験の検討
- 婦人科癌末期の難治性イレウスに対する減圧目的の経皮的内視鏡的胃瘻造設について
- 子宮体癌の保存的治療後妊娠での前置癒着胎盤に対し内腸骨動脈バルーン留置下で帝王切開および子宮全摘術を施行した1例
- 当科の卵巣粘液性腺癌の治療成績 : ─リンパ節郭清の適応についての考察
- 妊娠糖尿病を合併した高度肥満妊婦の分娩誘発の1例