It stimulates melanocytes to produce melanin, and can also be cleaved into smaller peptides. In humans, γ-lipotropin, β-MSH, and β-endorphin, are all possible fragments of β-lipotropin.
β-Lipotropin also performs lipid-mobilizing functions such as lipolysis and steroidogenesis. β-Lipotropin is the predominant opioid of the anterior human and rat pituitary gland. It is found in essentially equimolar concentrations to that of corticotropin. Evidence shows that β-Lipotropin is metabolized into endorphins that can greatly affect mood and behavior and is thus regarded as a prohormone.
γ-lipotropin is the amino-terminal peptide fragment of β-lipotropin. In humans, it has 56 amino acids. Gamma lipotropin is identical to the first 56 amino acid sequences of β-lipotropin. It can be cleaved to β-melanocyte stimulating hormone.
Lipotropin has also, under its alternate name AOD-9604 (Anti-Obesity Drug-9604), been connected with controversies in Australian Rules Football. Allegations have arisen around the use of the drug and its administration to players of the Essendon Football Club as a supplement, including weekly administration to players in the 2012 season. The matters are currently under investigation due to the relationship between Lipotropin and growth hormones, as noted by club medical staff.
^Lazarus, L H; Ling, Guillemin (June 1, 1976). "beta-Lipotropin as a prohormone for the morphinomimetic peptides endorphins and enkephalins". Proceedings of the National Academy of Sciences of the United States of America PNAS, Proceedings of the National Academy of Sciences73 (6): 2156–2159. doi:10.1073/pnas.73.6.2156.