QuestionSBA
QuestionChoice
The thyroid hormones, thyroxine (T4) and triiodothyronine (T3) are lipid-soluble molecules. Therefore, levothyroxine, as a synthetic form of T4, needs to be lipophilic to mimic the properties of the natural hormone. The cell membrane is primarily composed of a lipid bilayer. Lipophilic substances, like levothyroxine, have the advantage of being able to pass through the lipid bilayer of cell membranes efficiently.
10025391
b
Hydrophilic, diffuses through cell membrane
QuestionChoice
The thyroid hormones, thyroxine (T4) and triiodothyronine (T3), are lipid-soluble molecules. Therefore, levothyroxine, as a synthetic form of T4, needs to be lipophilic to mimic the properties of the natural hormone. The cell membrane is primarily composed of a lipid bilayer. Lipophilic substances, like levothyroxine, have the advantage of being able to pass through the lipid bilayer of cell membranes efficiently. It does not require vesicles to be transported.
10025394
e
Lipophilic, transported in vesicles
QuestionChoice
The thyroid hormones, thyroxine (T4) and triiodothyronine (T3) are lipid-soluble molecules. Therefore, levothyroxine, as a synthetic form of T4, needs to be lipophilic to mimic the properties of the natural hormone. The cell membrane is primarily composed of a lipid bilayer. Lipophilic substances, like levothyroxine, have the advantage of being able to pass through the lipid bilayer of cell membranes efficiently. It does not require carrier proteins to be transported; these are normally for hydrophilic molecules.
10025392
c
Hydrophilic, transport mediated by carrier proteins
QuestionChoice
The thyroid hormones, thyroxine (T4) and triiodothyronine (T3) are lipid-soluble molecules. Therefore, levothyroxine, as a synthetic form of T4, needs to be lipophilic to mimic the properties of the natural hormone. The cell membrane is primarily composed of a lipid bilayer. Lipophilic substances, like levothyroxine, have the advantage of being able to pass through the lipid bilayer of cell membranes efficiently. It does not require carrier proteins to be transported, these are normally for hydrophilic molecules.
10025393
d
Lipophilic, transport mediated by carrier proteins
QuestionChoice
This is the correct answer. The thyroid hormones, thyroxine (T4) and triiodothyronine (T3) are lipid-soluble molecules. Therefore, levothyroxine, as a synthetic form of T4, needs to be lipophilic to mimic the properties of the natural hormone. The cell membrane is primarily composed of a lipid bilayer. Lipophilic substances, like levothyroxine, have the advantage of being able to pass through the lipid bilayer of cell membranes efficiently.
10025390
a
Lipophilic, diffuses through cell membrane
Concept
Chapter
2693
5835
Levothyroxine
Topic
220
Endocrine Pharmacology
17476
A 30 year old woman with hypothyroidism attends a routine review with her GP. She is prescribed levothyroxine, which she understands targets thyroid hormone receptors.

Which of the following best describes the biochemical properties of levothyroxine?
a