Lipotropin
Encyclopedia
Lipotropin is a hormone
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...

 produced by the cleavage of pro-opiomelanocortin (POMC). The anterior pituitary gland
Anterior pituitary
A major organ of the endocrine system, the anterior pituitary, also called the adenohypophysis, is the glandular, anterior lobe of the pituitary gland...

 produces the pro-hormone POMC, which undergoes cleavage to adrenocorticotropin
Adrenocorticotropic hormone
Adrenocorticotropic hormone , also known as 'corticotropin', 'Adrenocorticotrophic hormone', is a polypeptide tropic hormone produced and secreted by the anterior pituitary gland. It is an important component of the hypothalamic-pituitary-adrenal axis and is often produced in response to biological...

 (ACTH) and β-lipotropin (β-LPH).

β-Lipotropin

β-Lipotropin is a 90-amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

 polypeptide that is the carboxy-terminal fragment of POMC.

It stimulates melanocytes to produce melanin
Melanin
Melanin is a pigment that is ubiquitous in nature, being found in most organisms . In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms...

, and can also be cleaved into smaller peptides. In humans, γ-lipotropin, α-MSH, β-MSH, γ-MSH, α-endorphin, β-endorphin, γ-endorphin, and met-enkephalin
Met-enkephalin
[Met]enkephalin, sometimes referred to as opioid growth factor , is a naturally-occurring, endogenous opioid peptide that has opioid effects of a relatively short duration. It is one of the two forms of enkephalin, the other being [leu]enkephalin...

 are all possible fragments of β-lipotropin.

β-Lipotropin also performs lipid-mobilizing functions such as lipolysis
Lipolysis
Lipolysis is the breakdown of lipids and involves the hydrolysis of triglycerides into free fatty acids followed by further degradation into acetyl units by beta oxidation. The process produces Ketones, which are found in large quantities in ketosis, a metabolic state that occurs when the liver...

 and steroidogenesis.

γ-Lipotropin

γ-lipotropin is the amino-terminal peptide fragment of β-lipotropin. In humans, it has 56 amino acids.

External links

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