Intra- and extra-cellular sources of T3 binding to putative thyroid hormone receptors in liver, kidney, and gill nuclei of immature rainbow trout,Oncorhynchus mykiss
✍ Scribed by MacLatchy, D. L. ;Eales, J. G.
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 754 KB
- Volume
- 262
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
The sources of extracellular and intracellular 3,5,3′ ‐triiodo‐L‐thyronine (T~3~) binding to putative thyroid hormone receptors in liver, kidney, and gill nuclei were determined in vivo for immature rainbow trout at 12°C. Both [^131^I]T~3~ and [^125^I]T~4~ were injected intraperitoneally, the plasma and tissues were examined at isotopic equilibrium at 20 h, and the proportions of intracellular [^125^I]T~3~ and extracellular [^131^I]T~3~ saturably bound in the nucleus were determined. Comparable total amounts of T~3~ were saturably bound in the nuclei of liver (7.2), kidney (8.0), and gill (9.7 moles × 10^−13^ .mg DNA^−1^), but the percentage of nuclear T~3~ generated within the target cell was greater for gill (76%) than for liver (50%) and kidney (28%). Both gill and liver possess a low Km T~4~ 5′monodeiodinase which could be responsible for the high proportion of the nuclear T~3~ generated within those tissues. © 1992 Wiley‐Liss, Inc.