Question about hormones.?

Question

Why would a hormone have to produce its effects through a second messenger system?

thanks

Answer 1

The first thing to understand is that hormones are released in small amounts into the bloodstream, so they are present in a very low concentration.

Hormones use second messenger systems to amplify the signal sent to a cell.

Say for example, the hormones job is to turn on a group of enzymes within the cell. Rather than having the hormone itself turn on all the copies of the enzyme, it binds to a receptor which makes lots and lots of second messengers rapidly. The second messengers are carrying the same message (turn on the enzymes), it's just that there are lots more of them.

As a result, all of the enzymes are activated much more rapidly because the signal has been amplified, and amplified only where it is needed (because the hormone only binds to cells with a receptor, ie specificity)

The body can regulate itself more efficiently this way, only producing a little bit of hormone which targets only cells with specific receptors, and once they reach that cell, they trigger an amplification of the signal to be sure the message is received.