Moriyama M, Nakanishi Y, Tsuyama S, Kannan Y, Ohta M, Sugano T
Department of Veterinary Physiology, College of Agriculture, Osaka Prefecture University, Japan.
Am J Physiol. 1997 Jul;273(1 Pt 2):R153-60. doi: 10.1152/ajpregu.1997.273.1.R153.
The conversion of beta- to alpha-adrenergic glycogenolysis by corticosteroids was studied in perfused livers of mature female rats. Isoproterenol stimulated glucose production more effectively in female rats than in male rats, but the difference in its stimulatory effect disappeared in adrenalectomized (ADX) rats, whereas it remained in adrenodemedulated rats. When ADX female rats were treated with dexamethasone sulfate, alpha-responses increased and beta-responses decreased, depending on the concentration of dexamethasone sulfate. The treatment of female rats with 1.5 mg/kg dexamethasone sulfate changed the levels of the alpha- and beta-responses to those observed in male rats, and the changes were associated with changes in the number of receptors. Although periodicity of changes in plasma corticosterone levels was observed in both male and female rats, the extent of circadian variations was significantly lower in female rats during the estrous cycle than in male rats. The variations in plasma corticosterone levels and in both alpha- and beta-responses after ovariectomy approached those in male rats. The results suggest that the level of plasma corticosterone might play an important role in the regulation of the relative levels of alpha- and beta-adrenergic responses in female rats.
在成年雌性大鼠的灌注肝脏中研究了皮质类固醇将β-肾上腺素能糖原分解转化为α-肾上腺素能糖原分解的过程。异丙肾上腺素在雌性大鼠中比在雄性大鼠中更有效地刺激葡萄糖生成，但在肾上腺切除（ADX）大鼠中其刺激作用的差异消失了，而在肾上腺去调制大鼠中差异仍然存在。当用硫酸地塞米松处理ADX雌性大鼠时，α反应增加而β反应减少，这取决于硫酸地塞米松的浓度。用1.5mg/kg硫酸地塞米松处理雌性大鼠会使α和β反应水平变为在雄性大鼠中观察到的水平，并且这些变化与受体数量的变化有关。尽管在雄性和雌性大鼠中均观察到血浆皮质酮水平的周期性变化，但在发情周期中雌性大鼠的昼夜变化程度明显低于雄性大鼠。卵巢切除后血浆皮质酮水平以及α和β反应的变化接近雄性大鼠。结果表明，血浆皮质酮水平可能在调节雌性大鼠α和β肾上腺素能反应的相对水平中起重要作用。
