Question

For each precursor molecule, identify the corresponding class of hormone (catecholamine, eicosanoid, peptide, or steroid) and give an example.

(a) arachidonic acid

(b) cholesterol

(c) prohormone

(d) tyrosine

Answer 1

a) Arachidonic acid is the precursor of eicosanoid class of hormones.

Example-Prostaglandins are hormone like substances that participate in a wide range of body functions such as contraction and relaxation of smooth muscles, dilation and construction of blood vessels, control of blood pressure and inflammation.

b) Cholesterol is the precursor of steroid hormones.

Example- estrogen is a female sex hormone that is responsible for development of secondary sexual characters and regulating the female reproductive cycle.

c) Prohormone is the precursor of peptide hormones.

Example-Insulin is a peptide hormone with a pro hormone named pro insulin. Insulin maintains the blood glucose level in our body by signalling the glucose uptake from blood to major tissues in the body like liver, fat cells and muscles.

d) Tyrosine is the precursor of catecholamines.

Example- Epinephrine also called adrenaline is called fight or flight hormone because it is secreted in emergency and during stressful situations. It increases cardiac output and blood glucose levels.