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A functional shift of urea-producing site from extraembryonic yolk sac to liver in the developing embryos of two oviparous cartilaginous fishes
conference contribution
posted on 2023-05-24, 13:40 authored by Tagaki, W, Kajimura, M, Tanaka, H, Bell, JD, Hyodo, SFor adaptation to high-osmolality marine environment, cartilaginous fish retain a high systemic concentration of urea. Although the composition of embryonic body fluid was similar to that in adult fish, urea-producing organ has not been identified in developing embryo. Therefore, we investigated the mRNA expression profiles of ornithine urea cycle (OUC) enzymes in two oviparous species. The expression of OUC enzyme genes was detected in the embryonic body, and remarkably increased to hatching, presumably due to the liver growth. The mRNA expression was also found in extraembryonic yolk sac membrane (YSM). The mRNA level of rate-limiting carbamoyl phosphate synthetase III was much higher in the YSM than that in the embryonic body during early stages of development. Our results demonstrate that the YSM makes an important contribution to the ureosmotic strategy of oviparous embryos, and that a functional shift of urea-producing site from YSM to embryonic liver occurs during the development.
History
Publication title
Abstract Book for the International Congress on the Biology of FishEditors
D MacKinlayPagination
228Department/School
Institute for Marine and Antarctic StudiesEvent title
The International Congress on the Biology of Fish 2014Event Venue
Edinburgh, ScotlandDate of Event (Start Date)
2014-08-03Date of Event (End Date)
2014-08-07Repository Status
- Restricted