Which of the following list includes ONLY first messengers? A) cortisol, insulin, prostaglandins B) nitric oxide, estradiol, heme C) insulin, glucagon, glucose D) Ca²⁺, testosterone, protein kinase A

Question

Quizplus · Accepted Answer

Cortisol, insulin, and prostaglandins are all first messengers, meaning they are the primary signaling molecules that bind to receptors on the cell surface to initiate a biochemical response.

Option B includes nitric oxide and heme, which can act as both first messengers and second messengers. Estradiol is a hormone that acts as a second messenger by binding to intracellular receptors.

Option C includes hormones related to glucose homeostasis and transport, but they act as both first and second messengers depending on the specific signaling pathway.

Option D includes a mix of second messengers (Ca2+, S1P, protein kinase A) and a hormone (testosterone) that acts as a second messenger by binding to intracellular receptors.

Which of the Following List Includes ONLY First Messengers