guanidinosuccinic-acid and guanidinopropionic-acid

An improved GC method in terms of sensitivity and decrease in the analysis time has been developed for the analysis of eight guanidino compounds: guanidine (G), methylguanidine (MG), creatinine (CTN), guanidinoacetic acid (GAA), guanidinobutyric acid (GBA), guanidinopropionic acid (GPA), argenine (Arg), and guanidinosuccinic acid (GSA), using isovaleroylacetone (IVA) and ethyl chloroformate (ECF) as derivatizing reagents. The separation was obtained from column HP-5 (30 m × 0.32 mm i.d.) with film thickness of 0.25 μm within 11 min. The linear calibrations were obtained with 0.5 to 50 μg/mL with coefficient of determination (R(2)) within 0.9969 - 0.9998. Limits of detections (LODs) were within 5 - 140 ng/mL. The derivatization, separation and determination was repeatable (n = 6) with relative standard deviation (RSD) within 1.2 - 3.1%. The guanidino compounds were determined in deproteinized serum of healthy volunteers and uremic patients within below LOD to 8.8 μg/mL and below LOD to 43.99 μg/mL with RSD within 1.4 - 3.6%. The recovery of guanidino compounds calculated by standard addition from serum was within 96.1 - 98.9%, with RSD 1.4 - 3.6%.

Topics: Acetone; Arginine; Boric Acids; Butyrates; Butyric Acid; Calibration; Chromatography, Gas; Creatinine; Formic Acid Esters; Glycine; Guanidine; Guanidines; Healthy Volunteers; Humans; Hydrogen-Ion Concentration; Ketones; Limit of Detection; Methylguanidine; Propionates; Reference Values; Reproducibility of Results; Succinates; Uremia

Antidiuresis and renal diseases alter the levels of guanidino compounds (GCs) in various tissues. Therefore, we hypothesized that diuresis could also disturb GC metabolism, storage, and elimination. In this study, rats were made diuretic to analyze GC levels in plasma, urine, and kidneys. Furosemide was chosen because of its wide use in various human pathologies. Rats were injected intraperitoneally 5 or 10 mg furosemide spread over a 24-hour cycle. Urine was collected over a period of 24 hours before and during furosemide treatment. Plasma was obtained from arterial blood. Renal zones were dissected. The GCs were determined by liquid chromatography. Five milligrams of furosemide provoked a significant increase in plasma and urine levels of GCs compared with those of the controls. The renal distribution and content of GCs were weakly modified by furosemide except for methylguanidine (MG). The level of MG was enhanced by 10 to 16 times in all renal zones. The MG level was 60% higher in renal zones of rats treated with 10 rather than 5 mg furosemide. The fractional excretion of MG was decreased by furosemide. Our data suggest that MG accumulation in kidney and plasma was caused by furosemide, which might induce MG synthesis, and that MG washout from tissue cells into urine by furosemide through the kidney may cause an increase in MG in the kidney.

Topics: Animals; Creatinine; Diuretics; Furosemide; Guanidines; Kidney; Male; Methylguanidine; Propionates; Rats; Rats, Sprague-Dawley; Succinates

The use of anisoin as pre-chromatographic reagent for LC analysis of guanidino compounds is proposed. The reagent reacts (5 min at 100 degrees C) with guanidino function and the resulting adducts can be chromatographed under reversed-phase conditions. A fluorescence detector (lambda(ex)=325 nm; lambda(em)=435 nm) was used to detect guanidino adducts. The derivatization and chromatographic conditions were optimised by a series of experiments. Application to the determination of arginine and creatine in pharmaceuticals and arginine, guanidine, methylguanidine, guanidinosuccinic acid, beta-guanidinopropionic acid, gamma-guanidinobutyric acid, guanidinoacetic acid and homoarginine in human urine is described. Quantitation limits ranged from 6 to 30 fmol, except for creatine (510 fmol).

Topics: Benzoin; Chromatography, Liquid; Guanidines; Pharmaceutical Preparations; Propionates; Succinates

Arginine (Arg) produced from citrulline originates mostly from kidneys. Arg is involved in guanidino compound biosynthesis, which requires interorgan co-operation. In renal insufficiency, citrulline accumulates in the plasma in proportion to renal damage. Thus, disturbances in Arg and guanidino compound metabolism are expected in several tissues. An original use of the model of nephrectomy based on ligating branches of the renal artery allowed us to investigate Arg and guanidino compound metabolism simultaneously in injured (left) and healthy (right) kidneys. The left kidney of adult rats was subjected to 72% nephrectomy. Non-operated, sham-operated and nephrectomized rats were studied for a period of 21 days. Constant renal growth was observed only in the healthy kidneys. Guanidino compound levels were modified transiently during the first 48 h. The metabolism and/or tissue content of several guanidino compounds were disturbed throughout the experimental period. Arg synthesis was greatly reduced in the injured kidney, while it increased in the healthy kidney. The renal production of guanidinoacetic acid decreased in the injured kidney and its urinary excretion was reduced. The experimentally proven toxins alpha-keto-delta-guanidinovaleric acid and guanidinosuccinic acid (GSA) accumulated only in the injured kidney. The urinary excretion of GSA and methylguanidine increased in nephrectomized rats. When the injured kidney grew again, the level of some guanidino compounds tended to normalize. Nephrectomy affected the guanidino compound levels and metabolism in muscles and liver. In conclusion, the specific accumulation of toxic guanidino compounds in the injured kidney reflects disturbances in renal metabolism and function. The healthy kidney compensates for the injured kidney's loss of metabolic functions (e.g. Arg: production). This model is excellent for investigating renal metabolism when a disease destroys a limited area in one kidney, as is observed in patients.

Topics: Acute Kidney Injury; Animals; Arginine; Creatine; Creatinine; Glycine; Guanidines; Homoarginine; Kidney; Kidney Failure, Chronic; Male; Methylguanidine; Muscle, Skeletal; Nephrectomy; Propionates; Rats; Rats, Sprague-Dawley; Succinates; Time Factors; Urea; Uremia

1. Guanidino compounds (GCs) have been quantified in different mammalian tissues such as brain, liver, muscle and kidney. The high anatomical heterogeneity of the kidney suggests that GCs could be unevenly distributed along the corticopapillary axis of the kidney in different species. 2. This study was designed to quantify twelve GCs in the different zones of rat and rabbit kidney. The kidneys were sliced and pieces of seven definite zones were weighed and homogenized for further GC extraction. GCs were determined by liquid chromatography. 3. The results indicate that: (1) GCs were unevenly distributed along rat and rabbit kidney; (2) qualitative and quantitative studies proved that each GC shows a particular distribution pattern along the corticopapillary axis for a given species; (3) in rats, alpha-keto-delta-guanidinovaleric acid, guanidinosuccinic acid, creatinine (CTN), methylguanidine and to a lesser extent gamma-guanidinobutyric acid increased steeply along the inner medulla in parallel to urea, whereas in rabbits, most of the GCs reached a plateau in the inner medulla and remained constant at this level; (4) gamma-guanidinobutyric acid was specifically found in the rat kidney; (5) argininic acid was higher in rabbit compared with rat kidney; (6) significantly higher levels of homoarginine were found in all zones of the rat kidney compared with the rabbit kidney. 4. The results suggest that: (1) GCs are mostly localized within the nephron segments; (2) an accumulation of GCs in the inner medulla might be explained either by a recycling process or by an intracellular storage as has been reported for urea, amino acids and organic osmolytes; (3) some GCs might be synthesized in nephron segments as reported for arginine (Arg) and guanidinoacetic acid (GAA); (4) several metabolic pathways of the GCs seemed to differ between rat and rabbit; (5) except for creatine, CTN, Arg and GAA, it seems unlikely that GCs might significantly increase the intracellular osmolality.

Topics: Affinity Labels; Animals; Arginine; Creatine; Glycine; Guanidines; Kidney; Male; Methylguanidine; Propionates; Rabbits; Rats; Rats, Sprague-Dawley; Succinates; Tissue Distribution; Urea

Using a specific HPLC analysis for guanidines, we find that rat aorta contains guanidino succinate (GS), guanidino acetate (GA), guanidino propionate (GP), guanidino butyrate (GB), methyl guanidine (MG) and guanidine. The concentration of L-arginine (0.05 nmol/mg tissue) is significantly lower than the other guanidines. GS is found to be the most potent vasodilator-guanidine in the rat aorta preparation and this vasodilation depends predominantly on the presence of the endothelium. This effect of GS is antagonized by NG-monomethyl L-arginine (L-NMMA), NW-nitro L-arginine benzyl ester (L-NABA), hemoglobin and by methylene blue, all of which are known to block or attenuate endothelium dependent relaxation. Further, the relaxation mediated by GS is accompanied by the formation of cGMP in the rat aorta. From these results we suggest that GS may be a major endogenous source of EDRF.

Topics: Animals; Aorta; Arginine; Cyclic GMP; Endothelium, Vascular; Glycine; Guanidines; Muscle Relaxation; Nitric Oxide; Propionates; Rats; Succinates