Fleck C, Engelbert K
Institute of Pharmacology and Toxicology, Friedrich Schiller University of Jena, Germany.
Exp Toxicol Pathol. 1998 Sep;50(4-6):356-64. doi: 10.1016/S0940-2993(98)80016-X.
The influence of triiodothyronine or dexamethasone on renal amino acid handling was investigated in anaesthetized, bile duct-ligated (DL) adult female rats. 3 days after DL, glomerular filtration rate (GFR) was unchanged whereas urine flow was decreased. Plasma concentrations of 5 out of 16 amino acids were significantly enhanced after DL. On the other hand, the fractional excretion (FE) of 11 out of 16 amino acids was significantly reduced as a sign of improved reabsorption capacity. Bolus injections of leucine (20 mg/100 g b.wt.), glutamine (45 mg/100 g b.wt.), or taurine (45 mg/100 g b.wt.) were followed by a temporary increase in the FE of the administered amino acids as well of the endogenous amino acids which were not administered. This phenomenon was more pronounced in DL than in control rats. Under load conditions, dexamethasone (60 microg/100 g b.wt.) or triiodothyronine (20 microg/100 g b.wt.) treatment for 3 days, i.p. once daily, was followed by a stimulation of renal amino acid reabsorption in DL rats. The increase in fractional amino acid excretion after amino acid load was significantly lower than in untreated rats. This effect was also more pronounced in DL rats.
在麻醉的、胆管结扎（DL）的成年雌性大鼠中，研究了三碘甲状腺原氨酸或地塞米松对肾脏氨基酸处理的影响。DL术后3天，肾小球滤过率（GFR）未改变，而尿流量降低。DL后，16种氨基酸中有5种的血浆浓度显著升高。另一方面，16种氨基酸中有11种的分数排泄（FE）显著降低，这表明重吸收能力提高。静脉注射亮氨酸（20mg/100g体重）、谷氨酰胺（45mg/100g体重）或牛磺酸（45mg/100g体重）后，给药氨基酸以及未给药的内源性氨基酸的FE会暂时增加。这种现象在DL大鼠中比在对照大鼠中更明显。在负荷条件下，每天腹腔注射一次地塞米松（60μg/100g体重）或三碘甲状腺原氨酸（20μg/100g体重），连续3天，随后DL大鼠的肾脏氨基酸重吸收受到刺激。氨基酸负荷后分数氨基酸排泄的增加显著低于未处理的大鼠。这种效应在DL大鼠中也更明显。
