| pubmed-article:7841190 | pubmed:abstractText | Thyroid hormones are responsible for a change in the expression of many target genes during amphibian metamorphosis. In this study we cloned and sequenced cDNAs encoding two of the five urea cycle enzymes, argininosuccinate lyase and arginase, from adult liver of Rana catesbeiana. The cDNAs for the bullfrog argininosuccinate lyase and arginase encoded proteins of 467 and 321 amino acids with predicted molecular weights of 52,257 and 35,088, which were 72-75 and 64-68% identical to the mammalian enzymes, respectively. The accumulation of the mRNAs for argininosuccinate lyase and arginase in liver increased 26 and 4-times in a coordinated manner during spontaneous metamorphosis. Thyroid hormone-treatment induced about 5 and 10-times accumulation of mRNAs for argininosuccinate lyase and arginase in liver from premetamorphosing tadpoles within 4 days. These results suggest that the mRNA levels of the two enzymes in liver are upregulated by thyroid hormone during metamorphosis. | lld:pubmed |
