College of Veterinary Medicine, The Ohio State University, Columbus, OH, United States of America.
United States Equestrian Federation, Columbus, Ohio, United States of America.
PLoS One. 2021 Jun 28;16(6):e0247542. doi: 10.1371/journal.pone.0247542. eCollection 2021.
Intravenous magnesium sulfate (MgSO4) is used in equine practice to treat hypomagnesemia, dysrhythmias, neurological disorders, and calcium dysregulation. MgSO4 is also used as a calming agent in equestrian events. Hypercalcemia affects calcium-regulating hormones, as well as plasma and urinary electrolytes; however, the effect of hypermagnesemia on these variables is unknown. The goal of this study was to investigate the effect of hypermagnesemia on blood parathyroid hormone (PTH), calcitonin (CT), ionized calcium (Ca2+), ionized magnesium (Mg2+), sodium (Na+), potassium (K+), chloride (Cl-) and their urinary fractional excretion (F) after intravenous administration of MgSO4 in healthy horses. Twelve healthy female horses of 4-18 years of age and 432-600 kg of body weight received a single intravenous dose of MgSO4 (60 mg/kg) over 5 minutes, and blood and urine samples were collected at different time points over 360 minutes. Plasma Mg2+ concentrations increased 3.7-fold over baseline values at 5 minutes and remained elevated for 120 minutes (P < 0.05), Ca2+ concentrations decreased from 30-60 minutes (P < 0.05), but Na+, K+ and Cl- concentrations did not change. Serum PTH concentrations dropped initially to rebound and remain elevated from 30 to 60 minutes, while CT concentrations increased at 5 minutes to return to baseline by 10 minutes (P < 0.05). The FMg, FCa, FNa, FK, and FCl increased, while urine osmolality decreased from 30-60 minutes compared baseline (P < 0.05). Short-term experimental hypermagnesemia alters calcium-regulating hormones (PTH, CT), reduces plasma Ca2+ concentrations, and increases the urinary excretion of Mg2+, Ca2+, K+, Na+ and Cl- in healthy horses. This information has clinical implications for the short-term effects of hypermagnesemia on calcium-regulation, electrolytes, and neuromuscular activity, in particular with increasing use of Mg salts to treat horses with various acute and chronic conditions as well as a calming agent in equestrian events.
静脉注射硫酸镁（MgSO4）在马临床上用于治疗低镁血症、心律失常、神经紊乱和钙调节异常。MgSO4 也被用作马术比赛中的镇静剂。高钙血症会影响钙调节激素以及血浆和尿液电解质；然而，高镁血症对这些变量的影响尚不清楚。本研究的目的是研究在健康马中静脉注射 MgSO4 后，高镁血症对甲状旁腺激素（PTH）、降钙素（CT）、离子钙（Ca2+）、离子镁（Mg2+）、钠（Na+）、钾（K+）、氯（Cl-）和其尿分数排泄（F）的影响。12 匹 4-18 岁、体重 432-600kg 的健康雌性马单次静脉注射 MgSO4（60mg/kg），在 360 分钟内不同时间点采集血样和尿样。在 5 分钟时，血浆 Mg2+浓度比基线增加 3.7 倍，在 120 分钟时仍保持升高（P < 0.05），Ca2+浓度从 30-60 分钟下降（P < 0.05），但 Na+、K+和 Cl-浓度没有变化。血清 PTH 浓度最初下降，然后反弹，从 30 分钟到 60 分钟保持升高，而 CT 浓度在 5 分钟时升高，在 10 分钟时恢复到基线（P < 0.05）。FMg、FCa、FK、FNa 和 FCl 增加，而尿液渗透压从 30-60 分钟与基线相比下降（P < 0.05）。短期实验性高镁血症改变钙调节激素（PTH、CT），降低血浆 Ca2+浓度，并增加健康马尿中 Mg2+、Ca2+、K+、Na+和 Cl-的排泄。这些信息对高镁血症对钙调节、电解质和神经肌肉活动的短期影响具有临床意义，特别是随着 Mg 盐在治疗各种急性和慢性疾病中的应用增加，以及在马术比赛中作为镇静剂的应用增加。
