143- Endocrine overview

Question 1

What are the three classes of hormones and how do they exert their action and what are they derived from?

Answer 1

Peptides- bind to membrane-bound receptors
Steroid derivatives- bind to cytoplasmic receptors, translocated into nucleus, bind to DNA as transcription factors. Derived from cholesterol
Amino Acid derivatives- Derived from tyrosine or catecholamines derived from phenylalanine. Bind to membrane bound receptors. Thyroid hormone traverses cell membrane, gets metabolized, then binds to nuclear receptor