Distribution of cathepsin E in the larval and adult organs of the bullfrogwith special reference to the mature form in the larval fore-gut

The distribution of cathepsin E in several organs of the bullfrog, Rana cat esbeiana, was analyzed at pre- and post-metamorphic stages by the acid prot einase assay, by visualization of enzyme activity on polyacrlamide fore-gut gels after electrophoresis and by immunoblotting with anti-cathepsin E ser um. Cathepsin E was mainly distributed in the foregut at the larval stage a nd in the stomach, duodenum, large intestine and gall bladder at the post-m etamorphic stage. In the larval fore-gut, a higher amount of the mature for m of cathepsin E was observed in addition to the preform, but in other orga ns, including the stomach at the post-metamorphic stage, the mature form wa s barely detected. Developmental changes in the amount of cathepsin E were found in the digestive tract and the gall bladder by quantitative immunoblo tting analysis. Finally, the larval fore-gut was stained immunohistochemica lly with anti-cathepsin E serum and the surface epithelium gave a strong im munoreactive signal. (C) 1998 Elsevier Science Inc. All rights reserved.