Johnstone L K, Mayhew I G
New Bolton Centre, University of Pennsylvania, 382 West Street Road, Kennett Square, Pennsylvania 19384, USA.
N Z Vet J. 2013 May;61(3):159-64. doi: 10.1080/00480169.2012.731682. Epub 2012 Nov 8.
To investigate the effects of lolitrem B intoxication on renal K(+) secretion in response to increased tubular flow rates.
Results are derived from a repeated measure pilot study of seven horses fed non-perennial ryegrass feed for a week prior to exposing them to perennial ryegrass seed and hay that contained an average of 2 ppm lolitrem B. At the end of the control and treatment period frusemide (1 mg/kg I/V) was administered and serial fractional excretion of K(+)(FEK(+)) and fractional excretion of Na(+)(FENa(+)) calculated. Baseline concentration of aldosterone in plasma, serum K(+)concentration and feed K(+) concentration were also compared.
Key findings included a reduced change in FEK(+) from 0 to 15 minutes in response to frusemide administration (p=0.022, Wilcoxon signed-rank test) and a reduced baseline concentration of aldosterone in plasma (p=0.022, Wilcoxon signed-rank test) during the treatment period compared with the control.
Results suggest that lolitrem B intoxication reduced flow-mediated K(+) secretion and interfered with aldosterone production or secretion. However, further investigation is required to validate these findings and to further elucidate the underlying pathophysiology.
Lolitrem B intoxication in horses may cause disruption to electrolyte handling in addition to neurological deficits.
研究洛替米星B中毒对肾小管流速增加时肾脏钾离子分泌的影响。
结果来自一项重复测量的试点研究，七匹马在接触平均含有2 ppm洛替米星B的多年生黑麦草种子和干草前一周，先喂食非多年生黑麦草饲料。在对照期和治疗期结束时，静脉注射速尿（1 mg/kg），并计算钾离子的连续排泄分数（FEK(+)）和钠离子的排泄分数（FENa(+)）。同时比较血浆中醛固酮的基线浓度、血清钾离子浓度和饲料钾离子浓度。
主要发现包括，与对照组相比，治疗期间静脉注射速尿后0至15分钟FEK(+)的变化减少（p=0.022，Wilcoxon符号秩检验），血浆中醛固酮的基线浓度降低（p=0.022，Wilcoxon符号秩检验）。
结果表明，洛替米星B中毒减少了流量介导的钾离子分泌，并干扰了醛固酮的产生或分泌。然而，需要进一步研究来验证这些发现，并进一步阐明潜在的病理生理学机制。
马的洛替米星B中毒除了导致神经功能缺损外，还可能引起电解质处理紊乱。
