Clark N B, Braun E J, Wideman R F
Am J Physiol. 1976 Oct;231(4):1152-8. doi: 10.1152/ajplegacy.1976.231.4.1152.
The renal handling of calcium, phosphate, sodium, and potassium was studied in normal and parathyroid extract (PTE)-injected starlings, Sturnus vulgaris. The birds were anesthetized with Equi-Thesin and infused intravenously with 2.5% mannitol containing [14C]inulin. Normal starlings actively reabsorb all four of these substances. After intravenous administration of 50 IU PTE/100 g body wt, the relative phosphate clearance (CPO4/CIn) as well as tubular transfer of phosphate (TPO4) increased significantly. Phosphate secretion occurred and usually persisted longer than 2 h. The relative calcium clearance also rose after PTE, but the TCa did not shift. This probably indicates that the tubular transport maximum (Tm) for calcium had been exceeded. The relative clearances of sodium and potassium also increased after PTE; however, only the rise in CNa/CIn was significantly different from the controls. The glomerular filtration rate (CIn) also increased significantly after PTE, but this effect was transient and cannot explain the longer lasting effects of PTE on excretion of phosphate, calcium, or sodium.
在正常和注射甲状旁腺提取物（PTE）的家八哥（Sturnus vulgaris）中研究了钙、磷、钠和钾的肾脏处理情况。用速眠新麻醉鸟类，并静脉注射含[14C]菊粉的2.5%甘露醇。正常家八哥会主动重吸收所有这四种物质。静脉注射50 IU PTE/100 g体重后，相对磷酸盐清除率（CPO4/CIn）以及磷酸盐的肾小管转运（TPO4）显著增加。出现了磷酸盐分泌，且通常持续超过2小时。PTE注射后相对钙清除率也升高，但钙的肾小管转运量（TCa）没有变化。这可能表明钙的肾小管转运极限（Tm）已被超过。PTE注射后钠和钾的相对清除率也增加；然而，只有钠清除率与肌酐清除率的比值（CNa/CIn）的升高与对照组有显著差异。PTE注射后肾小球滤过率（CIn）也显著增加，但这种作用是短暂的，无法解释PTE对磷酸盐、钙或钠排泄的更持久影响。
