Percorrer por autor "Richardson, S. J."
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- Comparative thyroid endocrinologyPublication . Richardson, S. J.; Power, Deborah; Klaren, PeterIt has been some time since comparative thyroidologists could meet in a dedicated symposium at a Conference of European Comparative Endocrinologists. Compared to peptide and steroid hormones, the biological activity of iodothyronines is determined by an increasing number of components and processes. Distributor proteins, transporters, deiodinases, conjugation and deconjugation pathways, receptors, and promoters all determine cellular and tissue specific responses to thyroid hormones. The two State-of-the-Art lectures which opened the symposium were ‘‘Novel developmental and cellular targets of thyroid hormone’’ (Barbara Demeneix) and ‘‘Thyroid hormone transporters’’ (Theo Visser). These had common themes reviewing new developments in the complexities of thyroid hormone signaling pathways.
- Developmentally regulated thyroid hormone distributor proteins in marsupials, a reptile, and fishPublication . Richardson, S. J.; Monk, Julie A.; Shepherdley, Caroline A.; Ebbesson, Lars O. E.; Sin, Frank; Power, Deborah; Frappell, Peter B.; Köhrle, Josef; Renfree, Marilyn B.Thyroid hormones are essential for vertebrate development. There is a characteristic rise in thyroid hormone levels in blood during critical periods of thyroid hormone-regulated development. Thyroid hormones are lipophilic compounds, which readily partition from an aqueous environment into a lipid environment. Thyroid hormone distributor proteins are required to ensure adequate distribution of thyroid hormones, throughout the aqueous environment of the blood, and to counteract the avid partitioning of thyroid hormones into the lipid environment of cell membranes. In human blood, these proteins are albumin, transthyretin and thyroxine-binding globulin. We analyzed the developmental profile of thyroid hormone distributor proteins in serum from a representative of each order of marsupials (M. eugenii; S.crassicaudata), a reptile (C. porosus), in two species of salmonoid fishes (S. salar; O. tshawytsch), and throughout a calendar year for sea bream (S. aurata). We demonstrated that during development, these animals have a thyroid hormone distributor protein present in their blood which is not present in the adult blood. At least in mammals, this additional protein has higher affinity for thyroid hormones than the thyroid hormone distributor proteins in the blood of the adult. In fish, reptile and polyprotodont marsupial, this protein was transthyretin. In a diprotodont marsupial, it was thyroxine-binding globulin. We propose an hypothesis that an augmented thyroid hormone distributor protein network contributes to the rise in total thyroid hormone levels in the blood during development.
- Evolution of the thyroid hormone-binding protein, transthyretinPublication . Power, Deborah; Elias, N. P.; Richardson, S. J.; Mendes, J.; Soares, M. C.; Santos, C. R. A.Transthyretin (TTR) belongs to a group of proteins, which includes thyroxine-binding globulin and albumin, that bind to and transport thyroid hormones in the blood. TTR is also indirectly implicated in the carriage of vitamin A through the mediation of retinol-binding protein (RBP). It was first identified in 1942 in human serum and cerebrospinal fluid and was formerly called prealbumin for its ability to migrate faster than serum albumin on electrophoresis of whole plasma.