Methoxamine, taurine levels

Figure 3. Effect of methoaximine on taurine levels in rat ventriclesy liver and hlood. Animals were killed seven or 24 hours after administration of 20 mg/kg of methoxamine. Control animals received saline. The number of animals in each group is shown in parentheses. (Mean S.E.)...

Administration of methoxamine, an a-agonist and vasoconstrictor, to rodents also produced a decrease in cardiac tissue and an increase in blood levels of taurine. On the other hand, taurine levels in the liver increased approximately 2.5- to 3-fold. While it is known that liver is capable of sequestering exogenous taurine, it can be calculated that the loss of taurine from the heart was quantitatively not sufficient to account for the increase in the liver. Thus the source of the increased taurine content of the liver is not known. Whether methoxamine stimulated de novo taurine synthesis in the liver or caused a loss of taurine from tissues other than the heart (such as skeletal muscle) which in turn was taken up by the liver requires further experimentation. 

The effects of ischemia on taurine levels were measured in three types of animal models ligation of the circumflex artery in the dog perfusion of rat hearts with oxygen-deficient buffer and administration of toxic doses of DL-isoproterenol and methoxamine. 

The taurine content of rat ventricular tissue was also signi-cantly reduced by methoxamine, an a-adrenergic agonist however, both liver and blood levels increased (Fig. 3). The administration... 

---