Carnosine Synthesis in Olfactory Tissue During Ontogeny: Effect of Exogenous β‐Alanine
Carnosine Synthesis in Olfactory Tissue During Ontogeny: Effect of Exogenous β‐Alanine
复制标题
个体发育过程中嗅觉组织肌肽的合成：外源性β-丙氨酸的影响
DOI：
10.1111/j.1471-4159.1985.tb08783.x
复制
发表时间：
1985
影响因子：
4.7
通讯作者：
A. Farbman
中科院分区：
文献类型：
--
作者：
E. L. Margolis;M. Grill;T. Kawano;A. Farbman
摘要：肌肽已被证实存在于妊娠第16天的大鼠嗅觉黏膜中。这种二肽的组织含量在胎儿和出生后逐渐增加。早在妊娠13-14天，放射性肌肽就可以从[14C]β -丙氨酸培养的胚胎大鼠嗅粘膜中分离出来。掺入量也随着外植体的初始年龄和培养时间的增加而逐渐增加，这表明嗅觉组织的肌肽合成能力在体外成熟。为了测试β -丙氨酸水平是否限制了肌肽的合成，我们评估了β -丙氨酸水平升高对组织肌肽含量的影响。在体内和体外实验中，外源性β -丙氨酸引起了不同年龄组织肌肽含量的增加。在成年动物的嗅球、嗅肌和骨骼肌中观察到这种增加。然而，肌肽合成酶活性没有相关的改变。此外，肌肽在嗅觉组织和肌肉中的不同半衰期似乎没有改变，这表明对降解酶没有任何影响。因此，组织肌肽水平至少部分地受到底物可利用性的调节。肌肽合成能力在产前发育早期的出现表明，这种酶的活性应该是研究嗅觉神经元成熟早期事件的有价值的援助。
Abstract: Carnosine has now been demonstrated by chemical analysis to be present in rat olfactory mucosa on day 16 of gestation. The tissue content of this dipeptide then increases progressively during fetal and postnatal life. Radioactive carnosine can be isolated from cultured embryonic rat olfactory mucosa incubated with [14C]β‐alanine as early as 13–14 days of gestation. The amount of incorporation also increases progressively with the initial age of the explant and with time in culture indicating in vitro maturation of the carnosine synthesis capability of olfactory tissue. To test whether the level of β‐alanine was limiting the synthesis of carnosine, we evaluated the effect of elevated β‐alanine levels on tissue carnosine content. Exogenous β‐alanine caused an increase in the tissue content of carnosine at several ages in vivo and in vitro. In adult animals this increase was observed in olfactory bulb, olfactory muscosa, and skeletal muscle. However, there was no associated alteration in carnosine synthetase activity. In addition, the different half‐lives of carnosine in olfactory tissue and muscle seemed unaltered, arguing against any effect on degradative enzymes. Thus, tissue carnosine levels are regulated, at least in part, by substrate availability. The early appearance of carnosine synthetic capacity during prenatal development indicates that this enzyme activity should be a valuable aid in studying early events in olfactory neuron maturation.