CONTROL OF SODIUM AND POTASSIUM TRANSPORT BY THE NEPHRON

心钠素对环鸟苷的影响 环磷酸腺苷（cGMP）和环磷酸腺苷（cAMP）产生 用离体大鼠肾小管和肾小球进行了研究。 ANF（1 μ mol）增加离体肾小球cGMP的积累 35-内髓集合管20倍。 小 cGMP积累的增加被认为是对1微摩尔ANF的反应， 其他肾单位节段：近曲小管，近直 小管，细的下降肢，髓质厚的上升肢， 皮质集合管 剂量反应研究表明， cGMP积累增加的阈值为0.1-1纳摩尔ANF， 内髓集合管，肾小球内10-100纳摩尔。 内髓集合反应的阈值浓度 导管与报告的ANF循环水平大致相同， 对照组大鼠。 ANF（1微摩尔）并不改变cAMP的积累， 在髓质厚的上升肢或在 内髓集合管 根据这些结果，我们有 在离体灌注的内髓收集中的起始转运研究 确定ANF是否影响尿素、水或氯化钠 运输

The effects of atrial natriuretic factors (ANF) on cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) production by isolated renal tubules and glomeruli from rats has been investigated. ANF (1 micromolar) increased cGMP accumulation in isolated glomeruli 35-fold and in isolated inner medullary collecting ducts 20-fold. Small increases in cGMP accumulation were seen in response to 1 micromolar ANF in other nephron segments: proximal convoluted tubules, proximal straight tubules, thin descending limbs, medullary thick ascending limbs and cortical collecting ducts. Dose response studies revealed that the threshold for an increase in cGMP accumulation was 0.1-1 nanomolar ANF in inner medullary collecting ducts, and was 10-100 nanomolar in glomeruli. The threshold concentration for a response in inner medullary collecting ducts was approximately the same as reported circulating levels of ANF in control rats. ANF (1 micromolar) did not alter cAMP accumulation in the absence or presence of vasopressin in medullary thick ascending limbs or in inner medullary collecting ducts. Based on these results, we have initiated transport studies in isolated perfused inner medullary collecting ducts to determine whether ANF affects urea, water, or sodium chloride transport.