Fritz I B, Griswold M D, Louis B G, Dorrington J H
Can J Biochem. 1978 Sep;56(9):875-9. doi: 10.1139/o78-135.
The concentration of cholera toxin required for half-maximal stimulation of cAMP production by Sertoli cell enriched cultures (4.48 X 10(2) microgram/ml) is greater than that required for half-maximal stimulation of 17beta-estradiol synthesis from testosterone (2.34 X 10(-4) microgram/ml), [3H]thymidine incorporation into DNA (1.48 X 10(-5) microgram/ml), or androgen binding protein production (2.43 X 10(-6) microgram/ml). The same relative dose response hierarchy was obtained with respect to stimulation of Sertoli cells with follicle stimulating hormone (FSH) preparations. Again, highest concentrations were required to elicit maximal cAMP production. The data are discussed in relation to an apparent paradox: If cAMP is the mediating 'second messenger' following stimulation by FSH or cholera toxin, why should highest concentrations of these agents be required to elicit 50% of maximal cAMP levels?
富集支持细胞的培养物产生半最大刺激的环磷酸腺苷（cAMP）所需的霍乱毒素浓度（4.48×10²微克/毫升），高于从睾酮合成半最大刺激的17β-雌二醇所需的浓度（2.34×10⁻⁴微克/毫升）、[³H]胸苷掺入DNA所需的浓度（1.48×10⁻⁵微克/毫升）或雄激素结合蛋白产生所需的浓度（2.43×10⁻⁶微克/毫升）。在用促卵泡激素（FSH）制剂刺激支持细胞方面，也获得了相同的相对剂量反应等级。同样，需要最高浓度才能引发最大的cAMP产生。针对一个明显的悖论讨论了这些数据：如果cAMP是在FSH或霍乱毒素刺激后起介导作用的“第二信使”，为什么需要这些试剂的最高浓度才能引发50%的最大cAMP水平？
