Silva P, Koenig B, Lear S, Eveloff J, Kinne R
Pflugers Arch. 1987 Jun;409(1-2):74-80. doi: 10.1007/BF00584752.
Because the medullary thick ascending limb of the loop of Henle is the target of several polypeptide hormones that stimulate adenyl cyclase in this nephron segment, we examined the effects of cyclic AMP on thick ascending limb of the loop of Henle cells isolated by enzymatic digestion and density gradient centrifugation from the outer medulla of the rabbit kidney. The functional parameter that was measured was transport dependent oxygen consumption. Oxygen consumption was measured using a polarographic oxygen electrode in a constant temperature chamber. We found that dibutyryl cyclic AMP inhibited oxygen consumption in a dose dependent way. Maximal inhibition was observed at a concentration of 10(-5) M. The effect of dibutyryl cyclic AMP was not present in the absence of either sodium, chloride or both implying that its effect is restricted to the sodium and chloride dependent oxygen consumption. The effect of dibutyryl cyclic AMP was additive to that of furosemide 10(-4) M while that of furosemide was not additive to that of cyclic AMP suggesting that the site of action of cyclic AMP is distal to that of furosemide. The effect of dibutyryl cyclic AMP was not additive to that of ouabain and was absent in cells where oxygen consumption was stimulated with amphotericin B in the absence of chloride indicating that it has no effect on Na-K-ATPase.(ABSTRACT TRUNCATED AT 250 WORDS)
由于亨氏袢髓质厚升支是几种多肽激素的作用靶点，这些激素可刺激该肾单位节段中的腺苷酸环化酶，因此我们研究了环磷酸腺苷（cAMP）对通过酶消化和密度梯度离心从兔肾外髓质分离出的亨氏袢厚升支细胞的影响。所测量的功能参数是与转运相关的氧消耗。使用极谱氧电极在恒温箱中测量氧消耗。我们发现二丁酰环磷酸腺苷（dibutyryl cyclic AMP）以剂量依赖的方式抑制氧消耗。在浓度为10^(-5) M时观察到最大抑制作用。在不存在钠、氯或两者都不存在的情况下，二丁酰环磷酸腺苷没有作用，这意味着其作用仅限于依赖钠和氯的氧消耗。二丁酰环磷酸腺苷的作用与10^(-4) M速尿的作用相加，而速尿的作用与环磷酸腺苷的作用不相加，这表明环磷酸腺苷的作用位点在速尿的作用位点远端。二丁酰环磷酸腺苷的作用与哇巴因的作用不相加，并且在用两性霉素B在无氯条件下刺激氧消耗的细胞中没有作用，这表明它对钠钾ATP酶没有影响。（摘要截短至250字）
