Learning Objectives
By the end of this section, you will be able to:
- Describe catabolic and anabolic hormones and function in the body
- Discuss the role of ATP in metabolism
- Describe the hormones that regulate anabolic and catabolic reactions
| Catabolic Hormones (Table 24.1) | |
|---|---|
| Hormone | Function |
| Cortisol | Released from the adrenal gland in response to stress; its main role is to increase blood glucose levels by gluconeogenesis (breaking down fats and proteins) |
| Glucagon | Released from alpha cells in the pancreas either when starving or when the body needs to generate additional energy; it stimulates the breakdown of glycogen (glycogenolysis) and the production of glucose (gluconeogenesis) in the liver to increase blood glucose levels; its effect is the opposite of insulin; glucagon and insulin are a part of a negative-feedback system that stabilizes blood glucose levels |
| Adrenaline/epinephrine | Released in response to the activation of the sympathetic nervous system; increases heart rate and heart contractility, constricts blood vessels, is a bronchodilator that opens (dilates) the bronchi of the lungs to increase air volume in the lungs, and stimulates gluconeogenesis |
| Anabolic Hormones (Table 24.2) | |
|---|---|
| Hormone | Function |
| Growth hormone (GH) | Synthesized and released from the pituitary gland; stimulates the growth of cells, tissues, and bones |
| Insulin-like growth factor (IGF) | Stimulates the growth of muscle and bone while also inhibiting cell death (apoptosis) |
| Insulin | Produced by the beta cells of the pancreas; plays an essential role in carbohydrate and fat metabolism, controls blood glucose levels, and promotes the uptake of glucose into body cells; causes cells in muscle, adipose tissue, and liver to take up glucose from the blood and store it in the liver and muscle as glycogen (glycogen synthesis); its effect is the opposite of glucagon; glucagon and insulin are a part of a negative-feedback system that stabilizes blood glucose levels |
| Testosterone | Produced by the testes in males and the ovaries in females; stimulates an increase in muscle mass and strength as well as the growth and strengthening of bone |
| Estrogen | Produced primarily by the ovaries, it is also produced by the liver and adrenal glands; its anabolic functions include increasing metabolism and fat deposition |
Disorders of the…Metabolic Processes: Cushing Syndrome and Addison’s Disease
As might be expected for a fundamental physiological process like metabolism, errors or malfunctions in metabolic processing lead to a pathophysiology or—if uncorrected—a disease state. Metabolic diseases are most commonly the result of malfunctioning proteins or enzymes that are critical to one or more metabolic pathways. Protein or enzyme malfunction can be the consequence of a genetic alteration or mutation. However, normally functioning proteins and enzymes can also have deleterious effects if their availability is not