Guides

Inhibins are ovarian and testicular hormones that suppress pituitary FSH by blocking activin receptor signalling.

ACTH is a 39-amino-acid pituitary peptide cut from POMC that drives adrenal cortisol production within the HPA axis feedback loop.

Pancreatic polypeptide is a 36-amino-acid hormone released from pancreatic islet cells after eating; this guide covers its structure, release and the small human infusion study on appetite.

Anti-Müllerian hormone (AMH) is a TGF-beta-family signalling protein made by Sertoli cells in the male fetus and by small growing ovarian follicles — here is what it does and what the blood test can and cannot tell you.

Cathelicidin LL-37 and the defensins are the human body’s main antimicrobial peptides; here is how they are made, how they differ and what research shows.

Mitochondria-derived peptides such as humanin and MOTS-c are small signaling peptides encoded inside mitochondrial rRNA genes; here is what the research does and does not show.

Thyrotropin-releasing hormone is a three-amino-acid peptide that starts the thyroid axis; here is how it is made, what it does and what the TRH test and taltirelin show.

GDF15 is a stress-responsive protein hormone that acts through the hindbrain receptor GFRAL; here is what research on nausea, metformin, pregnancy and cancer cachexia reports.

The amyloid-beta peptide is a 40-42 residue fragment of the amyloid precursor protein; here is how it is cut out, how it aggregates and what antibody trials measured.

Disulfide bonds in peptides are sulfur-sulfur links between cysteines that form rings, join chains and stabilise structure; here is how they form, break and are analysed.