Effect of a Single Dose of Triiodothyronine on the Uptake of (Methyl-¹⁴C) Choline into Chick Liver Phospholipids

Summary

The effects of a single dose of 3,3′-5-triiodothyronine (T₃) on the uptake of (methyl-¹⁴C) choline into liver phosphatidylcholine (PC) and lysophosphatidylcholine (LPC) were studied in chicks as a function of time up to 6 h after injection of the radioactive precursor. In all cases, chicks received the T₃ dose intraperitoneally 5 h before injection of the labelled compound.

T₃ enhances the incorporation of ¹⁴C-choline into liver PC, showing a biphasic response; the main uptake occurs between 2 and 3 h after administering the precursor. A smaller but significant hormone-dependent increase in incorporation of the labelled compound is observed in the case of LPC. Lipid P associated to PC and LPC remains constant throughout the experiment, and does not vary with hormone treatment. It is suggested that T₃-injection increases, either directly or through other metabolic processes, PC and LPC turnover in chick liver cells.

Key-Words:

Phospholipid Metabolism - Chick Metabolism - Triiodothyronine - Phosphatidylcholine - Lysophosphatidylcholine