Effect of ascorbic acid on guinea pig adrenal adenylate cyclase activity and plasma cortisol.
Effect of ascorbic acid on guinea pig adrenal adenylate cyclase activity and plasma cortisol.
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抗坏血酸对豚鼠肾上腺腺苷酸环化酶活性和血浆皮质醇的影响。
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
B. Litsios
中科院分区：
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作者：
N. Doulas;A. Constantopoulos;B. Litsios
肾上腺内抗坏血酸（阿萨）浓度对类固醇释放产生制动或调节作用。由于类固醇生成的变化是通过腺苷酸环化酶活性（ACL）的改变介导的，因此研究了不同阿萨血浆浓度对豚鼠肾上腺ACL活性和血浆皮质醇的影响。将42只雄性豚鼠随机分为以下7组：对照组、坏血病组和分别给予0.1、5、10、20或100 mg抗坏血酸/100 g体重的组。与对照动物相比，坏血病动物的阿萨水平非常低。血浆阿萨水平随阿萨剂量增加而升高。阿萨0.1 mg组的阿萨水平高于对照组。基础腺苷酸环化酶活性在动物组之间没有显著差异。相反，氟化钠刺激的ACL活性值显示随着阿萨剂量的增加而进行性降低。ACL活性降低与血浆阿萨浓度升高之间存在高度显著相关性。另一方面，在坏血病动物中，NaF反应性ACL活性高于任何其他组。坏血病组的平均皮质醇值高于对照组，这与高水平的NAF刺激的ACL活性相关。在给予0.1 mg阿萨的组中也发现了较高的平均皮质醇值，尽管该组中的ACL活性未受影响。这一发现，加上这些组中ACL活性降低，与大剂量阿萨对肾上腺皮质醇产生的抑制作用一致。上述数据可能表明，不同的血浆浓度的阿萨调节体内类固醇激素通过改变膜结合酶腺苷酸环化酶的活性。
Intra-adrenal ascorbic acid (AsA) concentrations exert a braking or modulating effect upon steroid release. Because changes in steroidogenesis are mediated through alterations in adenylate cyclase activity (ACL), the effect of varied AsA plasma concentrations on guinea pig adrenal ACL activity and plasma cortisol was studied. Forty-two male guinea pigs were randomly allocated to the following seven groups: controls, scorbutic, and groups given 0.1, 5, 10, 20 or 100 mg ascorbic acid/100 g body weight, respectively. Scorbutic animals had very low levels of AsA in comparison to control animals. Plasma AsA levels increased as AsA dose increased. The levels of AsA in the group given 0.1 mg AsA were higher than in controls. Basal adenylate cyclase activity did not vary significantly among animal groups. In contrast, values for NaF-stimulated ACL activity showed a progressive decrease with increasing AsA doses. A highly significant correlation was found between decreasing ACL activity and increasing plasma AsA concentrations. On the other hand, NaF-responsive ACL activity was higher in scorbutic animals than in any other group. Higher mean cortisol values were found in the scorbutic group than in the controls, correlating with high levels of NAF-stimulated ACL activity. Higher mean cortisol values were also found in the group given 0.1 mg AsA although ACL activity in this group was not affected. This finding, coupled with reduced ACL activity in these groups, is consistent with the inhibitory effect of a megadose of AsA on production of cortisol from the adrenal. The above data may suggest that differing plasma concentrations of AsA regulate in vivo steroidogenesis by altering the activity of the membrane-bound enzyme adenylate cyclase.