Which of These is a Lipid-Soluble Messenger

Question

Which of these is a lipid-soluble messenger?
A)Thyroid hormone
B)Protein kinase
C)Glucose
D)Sodium
E)Cyclic AMP

Accepted Answer

Lipid-soluble messengers are those that can pass through the plasma membrane of cells due to their hydrophobic nature. Thyroid hormone is a lipid-soluble messenger that can pass through the plasma membrane and bind to intracellular receptors to affect gene expression. Protein kinase, glucose, sodium, and cyclic AMP are not lipid-soluble messengers.