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Single-cell distribution of GAA synthesis

The enzymes AGAT and GAMT function together to synthesize creatine from arginine, glycine, and S-Adenosyl methionine. Deficiency in either enzyme or the creatine transporter, CT1, results in a devastating neurological disorder, Cerebral Creatine Deficiency Syndrome (CCDS). To better understand the pathophysiology of CCDS, we mapped the distribution of GATM and GAMT at single cell resolution, […]

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MCT12 as GAA influx and efflux transporter

Guanidinoacetate (GAA), which is a precursor of creatine, is mainly biosynthesized in the renal proximal tubular epithelial cells (RPTECs). Plasma concentration of GAA has been reported to be reduced in patients with monocarboxylate transporter 12 (MCT12) mutation (p.Q215X). However, the mechanism underlying GAA release from the RPTECs remains unclear. Therefore, to elucidate the role of […]

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Channeling of citrulline for renal synthesis of GAA

Although protein synthesis dominates the requirements for dietary amino acids, the need for amino acids to meet demand for synthesis of other compounds is not negligible. This is especially true of production of creatine, which requires substantial amounts of arginine and methionine. Synthesis of guanidino acetate (GAA), the precursor for creatine, constitutes the main pathway […]

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GAA metabolism and peripheral muscle fatigue

Exhaustive exercise induces various disturbances of homeostasis, with impaired bioenergetics often associated with strenuous muscular work. However, no study so far validated serum biomarkers of creatine metabolism vs. traditional markers of exhaustive exercise and fatigue. Here, we investigated how well changes in serum guanidinoacetic acid (GAA), creatine and creatinine correlate with responses in blood lactate, […]

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Kidneys, pancreas and gut as sources of GAA

Arginine:glycine amidinotransferase, necessary for the conversion of arginine (Arg) to guanidinoacetic acid (GAA), is expressed mainly in kidney and pancreas. The methylation of GAA to creatine (Cre) primarily occurs in the liver. The role of the gut in Cre homeostasis has not been characterized. We aimed to quantify the contribution of kidney, pancreas, and gut […]

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Age-related changes in serum GAA in women

Guanidinoacetic acid (GAA) is a fundamental intermediate in cellular bioenergetics, with circulating levels of GAA often reflects disturbances in its conversion due to many intrinsic and extrinsic factors, including gender or age. Here, we evaluated serum GAA in 172 healthy women aged 18 to 65 years, with age found to significantly predict serum GAA concentrations […]

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Creatine and GAA as biomarkers of muscular fitness

Elevated serum creatine and higher handgrip strength are individually associated with better health profiles yet the link between two variables remains unknown. In this cross-sectional study, we evaluated serum creatine levels in relation to handgrip strength in a cohort of 130 young healthy adults (61 women and 69 men; age 23.3 ± 2.6 years), while […]

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GABA transporters mediate GAA transport in brain

Guanidinoacetate (GAA) is a biosynthetic precursor of creatine, which plays a critical role in homeostasis of high-energy phosphates in the brain, but cerebral accumulation of GAA leads to neurological complications, such as epilepsy and seizures. The purpose of the present study was to clarify the contribution of the γ-aminobutyric acid (GABA) transport systems to GAA […]

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Urinary GAA as a marker of chicken intake

Improved assessment of meat intake with the use of metabolomics-derived markers can provide objective data and could be helpful in clarifying proposed associations between meat intake and health. The objective of this study was to identify novel markers of chicken intake using a metabolomics approach and use markers to determine intake in an independent cohort. […]

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Visceral fat inversely associated with urinary GAA

Obesity is a complex multifactorial phenotype that influences several metabolic pathways. Yet, few studies have examined the relations of different body fat compartments to urinary and serum metabolites. Anthropometric phenotypes (visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), the ratio between VAT and SAT (VSR), body mass index (BMI), waist circumference (WC)) and urinary and […]

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