Author: Carlos

Osteocalcin is a vitamin-K-dependent bone protein that was reclassified as a hormone in 2007 — then three independent knockout models failed to reproduce the endocrine effects.

FGF23 is made by bone cells and tells the kidney to dump phosphate. How a single cleavage site controls it, the mirror-image diseases it causes, and what burosumab does.

GnRH agonists and antagonists hit the same pituitary receptor and end at the same suppression, but only agonists pass through an initial testosterone surge — here is why, with the numbers from the FDA labels.

Insulin analogs change almost nothing about what insulin does and almost everything about when it does it. A tour of the ten residues that made it possible.

Collagen peptides are absorbed into human plasma – that much is solid. What happens after that is where the evidence gets thin, contested and heavily sponsor-funded.

Why the gut destroys swallowed peptides, what oral bioavailability really measures, and how SNAC and sodium caprylate got two peptides past the wall.

Oxyntomodulin is a 37-amino-acid gut peptide that activates both the GLP-1 and glucagon receptors. It never became a drug, but its pharmacology became the template for the dual and triple agonists that followed.

Prolactin is the one anterior pituitary hormone the brain restrains rather than releases. Here is how dopamine controls it, how its receptor signals, and the two assay artefacts that make prolactin results misleading.

C-peptide is the 31-amino-acid connector cut out of proinsulin when insulin is made — a diagnostic marker of endogenous insulin secretion, and the subject of a long-running debate about whether it does anything at all.

Deletions, aspartimide byproducts, epimers and counterions – the specific things that go wrong during peptide synthesis, and which ones an HPLC purity number can see.