The function of the lake sturgeon, Acipenser fulvescens, thyroid system and dietary effects

Abstract

The basic properties of the lake sturgeon ('Acipenser fulvescens ') thyroid system were studied to confirm and explain previously reported low plasma thyroid hormone (TH) levels. The THs from a variety of sturgeon tissues were extracted and assayed to determine their concentrations. Once the basic principles of the sturgeon thyroid system were established, the ability of sturgeon to modify thyroid function in response to changes in dietary constituents was studied. Two diets, ocean plankton and Martin's trout pellets, were fed to two groups of sturgeon. Finally the ability of the lake sturgeon to cope with a dietary induced T3-challenge was studied. In conclusion, the lake sturgeon thyroid system has several characteristics that differ from the teleost fish system. It is concluded that the lake sturgeon's thyroid system functions most similarly to organisms that live in low iodide environments like the mammals. (Abstract shortened by UMI.)