Meeting Abstract
P1.76 Sunday, Jan. 4 Identification and characterization of developmentally regulated serum thyroid hormone distributor proteins in sea lamprey, Petromyzon marinus. GROSS, T.N.; MANZON, R.G.*; Univ. of Regina, Biology; Univ. of Regina, Biology richard.manzon@uregina.ca
The lamprey appears to be the one vertebrate that contradicts the well-established anuran model of an increase in thyroid hormone (TH) concentrations initiating and driving metamorphosis. Previous studies have shown that unlike other vertebrates, goitrogen-treated larval lamprey undergo precocious metamorphosis, whereas, exogenous TH-treatments fail to induce metamorphosis. By identifying changes in the patterns of sea lamprey serum thyroid hormone distributor proteins (THDP) and their affinities for THs throughout development, we hoped to clarify if this difference is in part a physiological phenomenon related to TH availability or a fundamental difference in the role of THs in lamprey metamorphosis. The sea lamprey has four developmentally regulated serum THDP. The albumin-like glycoprotein AS is the dominant THDP in the sera of larval and metamorphosing phase sea lamprey. In stage seven of metamorphosis, three additional THDP appear, including the albumin-like SDS-1 glycoprotein, the glycolipoprotein CB-III, and an unidentified low molecular weight protein temporarily entitled Spot-3. In sera of parasite and spawning phase lamprey, SDS-1, CB-III are the main THDP. Despite the shift in the number and type of THDP densitometric and statistical analyses indicate there is only a marginally significant difference (p = 0.049) in total serum T4 and T3 binding capacities between sea lamprey phases. Lastly, preliminary data suggest that all four THDP bind T4 and T3 with similar affinities.
