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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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Synthesis of GAA and creatine in pancreas

Creatine is an important molecule involved in cellular energy metabolism. Creatine is spontaneously converted to creatinine at a rate of 1·7% per d; creatinine is lost in the urine. Creatine can be obtained from the diet or synthesised from endogenous amino acids via the enzymes arginine:glycine amidinotransferase (AGAT) and guanidinoacetate N-methyltransferase (GAMT). The liver has […]

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Creatine and GAA reference values

Creatine and guanidinoacetate are biomarkers of creatine metabolism. Their assays in body fluids may be used for detecting patients with primary creatine deficiency disorders (PCDD), a class of inherited diseases. Their laboratory values in blood and urine may vary with age, requiring that reference normal values are given within the age range. Despite the long […]

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BBB transport and cerebral distribution of GAA

Although the cerebral accumulation of guanidinoacetate (GAA) contributes to neurological complications in S-adenosylmethionine:guanidinoacetate N-methyltransferase (GAMT) deficiency, how GAA is abnormally distributed in the brain remains unknown. The purpose of this study was to investigate the transport of GAA across the blood-brain barrier (BBB) and in brain parenchymal cells in rats. [(14)C]GAA microinjected into the rat […]

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Serum GAA decreases after a moderate physical activity

Although many studies have focused on the effects of the physical activity on plasma homocysteine (Hcy) levels, the data gathered up to now are contradictory. In fact, it is true that some researches highlighted an exercise-induced fall in Hcy concentrations, but there are many reports proving that the physical exercise does not contribute to depress […]

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Creatine synthesis in the seminiferous epithelium

The testis synthesizes creatine from both arginine and glycine precursors, but when rat testicular tissue is separated into seminiferous tubules and interstitial cells, creatine synthesis occurs only in the tubular fraction. The purpose of the work presented here was to define the locus of creatine synthesis within the seminiferous tubules, by using cell separation and […]

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Utilisation of creatine and GAA by various CKs

We have investigated the utilisation of four analogues of creatine by cytosolic Creatine Kinase (CK), using 31P-NMR in the porcine carotid artery, and by mitochondrial CK (Mt-CK), using oxygen consumption studies in isolated heart mitochondria and skinned fibers. Porcine carotid arteries were superfused for 12 h with Krebs-Henseleit buffer at 22 degrees C, containing 11 […]

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Pancreatic acinar cells in the production of GAA

L-Arginine:glycine amidinotransferase (transamidinase) occurs at high concentrations in the kidney and the pancreas of rats. The cellular localization of transamidinase was investigated in fetal, neonatal, and adult rat pancreatic tissue using three indicators of the presence of transamidinase: (1) immunofluorescence microscopy, (2) in vitro enzymatic activity measurements on homogenates of whole pancreas and on isolated […]

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