Hormones that affect weight loss:
Insulin
Insulin is a protein chain or peptide hormone that is produced by the beta cells of the islets of Langerhans in the pancreas. The role of insulin is to lower blood sugar, deliver nutrients into cells that need it, and to store fat.
Insulin causes the liver, muscle, and fat tissue to take up glucose and turn it into glycogen in the muscles and the liver.
Insulin also prevents utilization of fat as an energy source. In absence of insulin, or when insulin levels are low, the body doesn’t take up glucose and fat is used as an energy source.
Insulin controls other systems in the body as well, and regulates amino acid uptake of the body’s cells.
Insulin has several other anabolic effects throughout the body as well.
Glucagon
Glucagon (also a peptide hormone) is secreted the by alpha cells of the islets of Langerhans in the pancreas. It’s role is to raise blood glucose levels. The pancreas releases glucagon when blood glucose levels are low.
Glucagon causes the liver to convert glycogen into glucose, which then is released in the bloodstream.
High blood glucose levels stimulate the release of insulin, which then in turn allows the glucose to be taken up, and used by insulin dependent tissues.
Glucose and insulin keep blood glucose levels stable.
Cortisol
Cortisol, also known as hydrocortisone, is a steroid hormone (or a glucocorticoid) produced by the zona fasciculate of the adrenal cortex. It is released in response to stress and low blood glucocorticoids.
It’s main functions are to raise blood glucose levels through gluconeogenesis, suppress the immune system, and assist in metabolizing proteins, fats and carbs.
It also decreases bone formation.
Release is controlled by the hypothalamus of the brain
Activates anti-stress and anti-inflammatory pathways.
In several studies, cortisol has been shown to (somewhat) suppress lipolysis or the breakdown of fat.
Leptin
Leptin plays a major role in regulating energy intake, expenditure, appetite, metabolism, as well as behavior. It’s one of the most important adipose-derived hormones.
Functions by binding to the leptin receptor.
Leptin tells the brain that the body has had enough to eat, thus producing a feeling of satiety. Leptin may make it easier to avoid the temptation of higher calorie foods.
Leptin’s ability to manipulate bone mass was first recognized in the year 2000. Leptin can affect bone metabolism.
Leptin receptors are in the hypothalamus and the hippocampus. Leptin deficiency has been proven to alter brain proteins and neural functions in obese mice.
In humans, low circulating plasma leptin has been linked to cognitive changes associated with anorexia, depression, HIV and the development of Alzheimer’s disease.
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