The lactating birds and the bees (gastrin, pepsin, etc)
Crop milkĀ is a secretion from the lining of theĀ cropĀ of parent birds that isĀ regurgitatedĀ to young birds. It is found among allĀ pigeons and dovesĀ where it is referred to asĀ pigeon milk. An analog to crop milk is also secreted from the esophagus ofĀ flamingosĀ and the maleĀ emperor penguin. D
Corticotropin-like intermediate [lobe] peptideĀ (CLIP)
Corticotropin-like intermediate [lobe] peptideĀ (CLIP), also known asĀ adrenocorticotropic hormone fragment 18-39Ā (ACTH(18-39)), is aĀ naturally occurring,Ā endogenousĀ neuropeptideĀ with aĀ docosapeptideĀ structureĀ and theĀ amino acid sequenceĀ Arg-Pro-Val-Lys-Val-Tyr-Pro-Asn-Gly-Ala-Glu-Asp-Glu
Pro-opiomelanocortinĀ (POMC)
Pro-opiomelanocortinĀ (POMC) is a precursorĀ polypeptideĀ with 241Ā amino acidĀ residues. POMC isĀ synthesizedĀ inĀ corticotrophsĀ of theĀ anterior pituitaryĀ from the 267-amino-acid-long polypeptide precursorĀ pre-pro-opiomelanocortinĀ (pre-POMC), by the removal of a 26-amino-acid-longĀ signal pept