Authors:H. Satake, M. Aoyama, T. Kawada, T. Sekiguchi, T. Sakai, M. Fujie, and Nori Satoh
Ci-TK and Ci-TK-R are authentic tachykinin (TK) and TK receptor isolated from a protochordate,
. In this study, we investigated a novel function of TK as an enhancer of oocyte growth. Ci-TK-R is expressed specifically in the
vitellogenic oocytes. Moreover, administration of Ci-TK to the
ovary resulted in upregulation of gene expression and enzymatic activity of several proteases. Moreover, maturation of the
oocytes from the vitellogenic stage to the post-vitellogenic stage was induced in the presence of Ci-TK, which was completely blocked by addition of protease inhibitors.