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Theophylline-Induced Hypocalcemia in Sheep
Teofyllin-inducerad hypokalcemi hos får
Acta Veterinaria Scandinavica volume 13, pages 484–491 (1972)
Abstract
Intravenous infusion of theophylline at rates of 1 and 2 mg/kg/min. caused marked hypocalcemia in intact sheep. The plasma concentration of NEFA increased. The lipolytic but not the hypocalcémie effect of theophylline was completely inhibited by nicotinic acid. This fact suggested that lipid mobilization and hypocalcemia were not related. The effects of parathyroid hormone are mediated by 3′, 5′AMP, and methyl xanthines are known to inhibit the inactivation of 3′, 5′AMP. There is, however, evidence in the literature that excessive amounts of 3′, 5′AMP inhibit rather than increase bone resorption. It was therefore suggested that the used amounts of theophylline caused an excessive accumulation of 3′, 5′AMP in bone tissue, so that bone resorption was inhibited and hypocalcemia developed.
Sammanfattning
Intravenös infusion av teofyllin (1 och 2 mg/kg/min.) förorsakade påtaglig hypokalcemi hos intakta får. Plasmakoncentrationen av NEFA ökade. Den lipolytiska men ej den hypokalcemiska effekten av teofyllin blockerades av nikotinsyra. Det föreföll således som om dessa effekter ej var kopplade. Effekterna av parathormon medieras av 3′, 5′AMP och metylxantiner blockerar effektivt inaktiveringen av 3′, 5′AMP. Det finns emellertid belägg för att excessiva mängder av 3′, 5′AMP hämmar benresorbtionen. Det förefaller därför troligt att teofyllin vid de använda doseringarna gav upphov till en excessiv ackumulering av 3′, 5′AMP i benvävnaden, så att benresorbtionen hämmades och hypokalcemi utvecklades.
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Luthman, J., Jonson, G. & Persson, J. Theophylline-Induced Hypocalcemia in Sheep. Acta Vet Scand 13, 484–491 (1972). https://doi.org/10.1186/BF03547154
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DOI: https://doi.org/10.1186/BF03547154