What is Glycine, Urine?
Glycine is the simplest amino acid and serves multiple biological roles — as an inhibitory neurotransmitter acting at strychnine-sensitive glycine receptors in the spinal cord and brainstem, as the most abundant amino acid in collagen (approximately 33% of collagen residues), as a substrate for glutathione synthesis alongside cysteine and glutamate, and as a participant in one-carbon metabolism and bile acid conjugation. Urinary glycine reflects a composite of protein catabolism, hepatic glycine conjugation reactions, and renal tubular handling rather than direct central glycinergic neurotransmission.