title: Glycine betaine excretion is not directly linked to plasma glucose concentrations in hyperglycaemia.
abstract: Diabetes mellitus subjects, type 1 and type 2, have increased glycine betaine excretion compared to normal subjects that correlated with plasma glucose and HbA(1C) concentrations. The current study was undertaken to determine whether elevated glucose concentration directly increases glycine betaine excretion in an animal model. Non-pregnant female Coopworth sheep received an intravenous glucose load (12.5,25 and 50% w/v; rate 200 ml/h) for 6 h followed by a 12 h physiological saline washout (0.9% w/v). Plasma and urine samples were analyzed for glycine betaine and glucose. Urine volumes and osmolality were also measured. Using the non-parametric Kruskal Wallis analysis of variance test we found no difference in glycine betaine excretion between glucose loaded and saline infused control animals (P=0.861). However, a significant negative correlation (r=-0.28, P<0.001) was observed between urine osmolality and glycine betaine excretion independent of treatment. We conclude that acute elevations of plasma glucose concentrations did not result in increased glycine betaine excretion and is therefore unlikely to be directly responsible for elevated glycine betaine excretion observed in diabetes mellitus subjects.
authors.affiliation: Department of Biochemistry, Canterbury Health Laboratories, PO Box 151, Christchurch, New Zealand. warwick.dellow@chmeds.ac.nz
authors.forename: W J
authors.initials: WJ
authors.lastname: Dellow
authors.forename: S T
authors.initials: ST
authors.lastname: Chambers
authors.forename: G K
authors.initials: GK
authors.lastname: Barrell
authors.forename: M
authors.initials: M
authors.lastname: Lever
authors.forename: R A
authors.initials: RA
authors.lastname: Robson
mesh_terms: D000818:Animals; D001622:Betaine / Q000652:urine*; D001786:Blood Glucose / Q000378:metabolism*; D003922:Diabetes Mellitus, Type 1 / Q000652:urine; D003924:Diabetes Mellitus, Type 2 / Q000652:urine; D004195:Disease Models, Animal; D005260:Female; D006029:Glycosuria; D006801:Humans; D006943:Hyperglycemia / Q000097:blood* / Q000652:urine*; D012756:Sheep; D018709:Statistics, Nonparametric; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D001622:Betaine