What is the name of the substances that the endocrine glands secrete blood?

These are hormones. They are secreted by various glands and perform specific functions. This can be the growth of the body (somatropin), increased heart rate (adrenaline), and others. Hormones are very important in our body, as they regulate almost all processes and feelings. The feeling of love, for example, is the action of neurotransmitters such as dopamine, oxytocin, serotin, adrenaline, and many others. Also, many hormones are injected intravenously in case of a deficiency, since this is a fast and reliable way of delivering a substance to the desired organ or tissue.