Question about hormone receptors?

Question

Why do some hormones have receptors on almost all cells, but other hormones only have receptors in a few tissues or organs?

Answer 1

Hormones are the bodies way of adjusting. There are many wide range hormones that have a large impact on the body like GH (growth hormone) and there are hormones that help the body perform specific functions when the time comes, FSH (follicle stimulating hormone, womans time of the month). Think about it this way, you wouldn't want prolactin,  which stimulates milk production in mammary cells, working on all cells, using up vital energy and resources to drown your body in milk.

The body is a very complex machine, thousands of years have smoothed out the kinks and provided certain hormones with certain functions. Many hormones simply regulate other hormones by "turning off" organs or reversing the action of a previous hormone. The main thing to think about is how the body maintains a homeostasis (equilibrium) in order to reach a healthy balance. There will always be a need for epinephrine and the "fight or flight response", but then again every now and then you get pregnant and just need some milk.

Answer 2

So that they will only attach to the correct target cells where they produce an effect.

Hope this helps!