NO activates a number of enzymes which, in turn, regulate vascular tone and activate ion channels. Growth factors are also paracrine signal molecules. There are many growth factors and they are often named for their target organ. We discussed their signaling in the last class. Prostaglandins are modified fatty acids.
Prostaglandins act in the reproductive system and in the immune system.
One of the targets of PGs is smooth muscle. Aspirin inhibits prostaglandin synthesis. Below, I have listed the major hormones. You should learn the function of the hormones, their site of action, their site of production, and what regulates their stimulus. Several organs are specialized for endocrine function.