Subject(s)
Acute Kidney Injury/diagnosis , Anti-Inflammatory Agents/therapeutic use , Antifibrinolytic Agents/therapeutic use , Hematuria/diagnosis , Methylprednisolone/therapeutic use , Thrombocytopenia/diagnosis , Vitamin K/therapeutic use , Acute Kidney Injury/blood , Acute Kidney Injury/etiology , Aged , Diagnosis, Differential , Disease Progression , Hematuria/complications , Hematuria/drug therapy , Humans , Male , Practice Guidelines as Topic , Thrombocytopenia/complicationsABSTRACT
OBJECTIVES: To establish whether normal human subjects excrete glycine betaine at a constant rate. DESIGN AND METHODS: Urine was collected from ten normal healthy male subjects for 14 days, during which fluid intake was systematically varied from <800 mL to >3 L per day. Glycine betaine, sorbitol and creatinine excretions were estimated per day and as millimole per mol creatinine. RESULTS: The intrasubject SD of urine glycine betaine was 3.5 mmol/mol creatinine, and the intersubject SD 5.8 mmol/mol creatinine. The intrasubject SD of plasma glycine betaine was 10.2 mol/L and the intersubject SD 14.2 mol/L. Water load had little effect on glycine betaine excretion and plasma glycine betaine. After 12 years, excretions and plasma concentrations tended to parallel the initial results. CONCLUSIONS: Normal subjects have consistent individual glycine betaine excretions that are not strongly influenced by urine volume. Abnormal excretions, or significant changes in excretion, can be interpreted as indicating a pathological process.
Subject(s)
Betaine/urine , Creatinine/urine , Sorbitol/urine , Adult , Age Factors , Betaine/blood , Chromatography, High Pressure Liquid , Humans , Male , Time FactorsABSTRACT
BACKGROUND: Glycine betaine is important in cell volume regulation and in remethylating homocysteine, a vascular risk factor. OBJECTIVE: We investigated changes in circulating glycine betaine concentrations in human volunteers both under acute osmotic stress and over longer time scales. DESIGN: Plasma glycine betaine concentrations were measured in normal human volunteers in three studies: (1) during acute diuresis and antidiuresis; (2) during prolonged diuresis for 5 days, and antidiuresis for 5 days followed by further diuresis for the final 5 days; (3) repeated samples taken 3 years apart. RESULTS: Circulating glycine betaine concentrations remained almost unchanged for several hours after acute diuretic or antidiuretic stresses. There was more (3-10-fold) interindividual variation than intraindividual variation. A similar pattern was found on day 15 of the study. In a 3-year follow-up, plasma glycine betaine concentrations on the two occasions were highly correlated with no systematic change, showing that individual set points remain stable for years. In contrast, there was no relationship among plasma proline betaine concentrations at these times. Urinary glycine betaine excretions measured 3 years apart were also found to correlate once the perturbing effect of dietary proline betaine excretion was allowed for. CONCLUSIONS: Human circulating glycine betaine is homeostatically controlled with a distinct control value for each individual. In contrast, peripheral blood concentrations of proline betaine, which is present in the diet (and has no known metabolic or physiological role in mammals), is not controlled.