Thyroid hormone deiodinases during embryonic development of the saltwater crocodile (Crocodylus porosus).
Caroline A Shepherdley, Samantha J Richardson, Barbara K Evans, Eduard R Kühn, Veerle M Darras
General and Comparative Endocrinology | Elsevier BV | Published : 2002
All tissues of the embryonic saltwater crocodile (Crocodylus porosus) gradually increased in weight during development except for lung tissue, which had a peak weight of 1.09 g at day 67, thereafter decreasing in weight. The brain was a relatively large organ. Deiodinase activities in liver, kidney, lung, heart, gut, and brain from day 29 to day 77 of development of the saltwater crocodile were investigated. High-K(m) reverse triiodothyronine (rT(3)) outer ring deiodination (ORD) activity was present in all tissues except the brain. Activity ranged from 559 +/- 51.3 pmol rT(3) deiodinated/mg protein/min in the liver at day 77 to below 10 pmol rT(3) deiodinated/mg protein/min in gut, lung, an..View full abstract