Principles of Biochemistry (2+1)

9.1.3 General Characteristics of Hormones

The hormones catalyze and control metabolic processes. The hormones differ from enzymes in the following ways: The hormones are produced in an organ function. They are secreted into the blood prior to use and reach another organ in which they ultimately perform their function. The action of a hormone is regulated by 4 factors.

(1) Rate of synthesis and secretion of the stored hormone from the endocrine gland.

(2) Specified transport system in the plasma.

(3) Hormone-specific receptors in target cell cytosol or membranes and

(4) Ultimate degradation of the hormone, usually by the liver or kidneys.