Anabolics

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Anabolism is the metabolic process that builds larger molecules from smaller ones. One way of categorizing metabolic processes, whether at the cellular, organ or organism level is as 'anabolic' or 'catabolic', which is the opposite. To put it another way, anabolic processes use up energy (endergonic) while catabolic processes produce energy (exergonic). Anabolism is powered by catabolism, where large molecules are broken down into smaller parts and then used up in respiration. Many anabolic processes are powered by adenosine triphosphate (ATP).

Anabolic processes tend toward "building up" organs and tissues. These processes produce growth and differentiation of cells and increase in body size, a process that involves synthesis of complex molecules. Examples of anabolic processes include growth and mineralization of bone and increase of muscle mass.

Because it is counterproductive to have anabolic and catabolic processes occurring in cells simultaneously, there are many signals that switch on anabolic processes while switching off catabolic processes and vice versa. Most of the known signals are hormones and the molecules involved in metabolism itself. Endocrinologists have traditionally classified many of the hormones as anabolic or catabolic.

Classic anabolic hormones

• Growth hormone
• IGF1 and other insulin-like growth factors
• Insulin
• Testosterone
• Oestrogen

Newer hormones associated with the balance of the catabolic and anabolic states include

• Orexin and Hypocretin (a hormone pair)
• Melatonin

See also

• Metabolism
• Anabolic steroid