Plasma methylguanidine and creatinine concentrations in cats with experimentally induced acute renal failure

Chromatography of guanidino compounds

Guanidino compounds involved in the urea and guanidine cycles have been found in serum of nephritic patients, and some guanidino compounds have been suspected to be uremic toxins. The simultaneous analysis of naturally occurring metabolites is important for diagnosis of diseases. In this review, liquid chromatographic analysis of natural metabolites of guanidino compounds are described. the information about arginine as a precursor of nitric oxide are included. The reports of pharmaceutical compounds having a guanidino group, peptides containing arginine and aminoglycosides are summarized in Table 1.

Creatine and creatinine metabolism

The goal of this review is to present a comprehensive survey of the many intriguing facets of creatine (Cr) and creatinine metabolism, encompassing the pathways and regulation of Cr biosynthesis and degradation, species and tissue distribution of the enzymes and metabolites involved, and of the inherent implications for physiology and human pathology. Very recently, a series of new discoveries have been made that are bound to have distinguished implications for bioenergetics, physiology, human pathology, and clinical diagnosis and that suggest that deregulation of the creatine kinase (CK) system is associated with a variety of diseases. Disturbances of the CK system have been observed in muscle, brain, cardiac, and renal diseases as well as in cancer. On the other hand, Cr and Cr analogs such as cyclocreatine were found to have antitumor, antiviral, and antidiabetic effects and to protect tissues from hypoxic, ischemic, neurodegenerative, or muscle damage. Oral Cr ingestion is used in sports as an ergogenic aid, and some data suggest that Cr and creatinine may be precursors of food mutagens and uremic toxins. These findings are discussed in depth, the interrelationships are outlined, and all is put into a broader context to provide a more detailed understanding of the biological functions of Cr and of the CK system.

Renal clearance of endogenous creatinine, urea, sodium, and potassium in normal cats and cats with chronic renal failure

The renal clearance test was carried out in 6 normal male cats and 12 male cats with chronic renal failure. The average concentrations of creatinine (Cr), urea, sodium (Na), and potassium (K) in the serum of the cats with chronic renal failure were 5.09, 136.7 (mg/100 ml), 143.9 and 3.71 (mEq/l) respectively, and the specific gravity of urine was 1.009. The renal clearances of Cr, urea, Na, and K (ml/min/kg of body weight) were 2.639 +/- 0.217, 1.034 +/- 0.110, 0.024 +/- 0.007 and 0.266 +/- 0.028, respectively in normal cats, and were 0.789 +/- 0.407, 0.358 +/- 0.211, 0.095 +/- 0.084 and 0.872 +/- 0.204 in cats with chronic renal failure. Clearance of Cr and urea was significantly lower in cats with chronic renal failure than in normal cats, while the values of Na and K were significantly higher in cats with chronic renal failure. The glomerular filtration of Cr and urea and the urinary excretion of these 4 substances were significantly higher in cats with chronic renal failure. The tubular reabsorption rates of Na and K were significantly lower in cats with chronic renal failure compared to those in normal cats, but there was no significant difference in urea and creatinine.