Stier C T, Cowden E A, Friesen H G, Allison M E
Endocrinology. 1984 Jul;115(1):362-7. doi: 10.1210/endo-115-1-362.
PRL is a pituitary hormone with important osmoregulatory properties in lower vertebrates and has been reported to decrease renal water and electrolyte excretion in mammals. Although several studies have suggested that the proximal tubule is the major site of action of PRL, no direct examination of such an effect has been made. In the present study we used micropuncture and clearance techniques to examine the effect of ovine PRL (oPRL) infusion on single nephron and whole kidney function in anesthetized volume-expanded rats pretreated with bromocriptine to suppress endogenous PRL release. oPRL infusion was associated with a significant reduction in urinary sodium, potassium, and water excretion compared to changes seen in the control group. There was no significant effect of oPRL on whole kidney glomerular filtration rate, renal plasma flow, filtration fraction, renal blood flow, renal vascular resistance, or arterial pressure compared to those in control rats. Single nephron studies failed to detect any significant effect of oPRL on single nephron glomerular filtration rate and absolute or fractional reabsorption by the proximal convoluted tubule. Although arginine vasopressin was detected in the oPRL preparation, the quantity infused was negligible compared to the plasma levels found in anesthetized rats prepared for kidney micropuncture. Our results suggest that oPRL exerts a renal tubular action separate from arginine vasopressin to decrease water and electrolyte excretion which occurs beyond the last superficial convolution of the proximal convoluted tubule.
催乳素是一种在下等脊椎动物中具有重要渗透调节特性的垂体激素，据报道在哺乳动物中可减少肾脏水和电解质排泄。尽管多项研究表明近端小管是催乳素的主要作用部位，但尚未对此效应进行直接检测。在本研究中，我们使用微穿刺和清除技术，在预先用溴隐亭抑制内源性催乳素释放的麻醉的容量扩张大鼠中，检测绵羊催乳素（oPRL）输注对单个肾单位和全肾功能的影响。与对照组相比，输注oPRL与尿钠、钾和水排泄的显著减少有关。与对照大鼠相比，oPRL对全肾肾小球滤过率、肾血浆流量、滤过分数、肾血流量、肾血管阻力或动脉血压均无显著影响。单个肾单位研究未能检测到oPRL对单个肾单位肾小球滤过率以及近端曲管的绝对或分数重吸收有任何显著影响。尽管在oPRL制剂中检测到了精氨酸加压素，但与为肾脏微穿刺准备的麻醉大鼠血浆水平相比，输注的量可以忽略不计。我们的结果表明，oPRL发挥与精氨酸加压素不同的肾小管作用，以减少近端曲管最后一个浅表曲段之后发生的水和电解质排泄。
