CONTENT - International Society of Zoological Sciences
CONTENT - International Society of Zoological Sciences
CONTENT - International Society of Zoological Sciences
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S23 ICZ2008 - Abstracts<br />
Organogenesis <strong>of</strong> digestive organs in vertebrates<br />
Sadao Yasugi<br />
Faculty <strong>of</strong> Pharmaceutical Science, Teikyo Heisei University, 2289,<br />
Uruido, Ichihara, Chiba 290-0193, Japan<br />
The embryonic digestive organs in the vertebrates consist <strong>of</strong><br />
endodermal epithelium and mesodermal mesenchyme. The former<br />
later fulfils functions such as production <strong>of</strong> digestive enzymes and<br />
absorption <strong>of</strong> nutrients, whereas the latter differentiates into<br />
connective tissue layers and smooth muscle layers. It has been<br />
well established that interactions between epithelium and<br />
mesenchyme are prerequisite for the normal development <strong>of</strong> the<br />
digestive organs. In general, the differentiation <strong>of</strong> the epithelium<br />
requires specific influence <strong>of</strong> the mesenchyme, and the<br />
differentiation <strong>of</strong> the mesenchyme and its nervous system is<br />
regulated by the epithelium.<br />
Recent studies carried out in my laboratory have revealed<br />
importance <strong>of</strong> some factors in the mesenchymal and epithelial<br />
tissues in the development <strong>of</strong> the chicken digestive organs,<br />
especially the stomach. For example, the determination <strong>of</strong> regional<br />
specificities <strong>of</strong> the epithelium in the primitive gut is <strong>of</strong>ten under the<br />
influence <strong>of</strong> the mesenchymal growth factors such as BMP, FGF<br />
and Wnt. On the other hand, the differentiation <strong>of</strong> the mesenchyme<br />
is controlled by sonic hedgehog expressed in the epithelium.<br />
The digestive organs possess essentially the same structures<br />
among the vertebrates. For example the stomach has glands cells<br />
<strong>of</strong> which produce and secrete digestive enzyme pepsin. The small<br />
intestine forms villus structures and epithelial cells produce<br />
dissacharidase and absorb nutrients. This means that factors<br />
acting in the development <strong>of</strong> the chicken digestive organs are also<br />
active in other vertebrates. In fact, above-mentioned growth actors<br />
and sonic hedgehog are known to be expressed in the developing<br />
stomach epithelium and mesenchyme <strong>of</strong> the mammals. Thus roles<br />
<strong>of</strong> these factors elucidated with he chicken embryo must also be<br />
important in other vertebrates.<br />
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