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Comparison of palmitic acid and glucose metabolism in the rabbit urinary bladder
Author(s) -
Hypolite Joseph A.,
Haugaard Niels,
Wein Alan J.,
Ruggieri Michael R.,
Levin Robert M.
Publication year - 1989
Publication title -
neurourology and urodynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 90
eISSN - 1520-6777
pISSN - 0733-2467
DOI - 10.1002/nau.1930080608
Subject(s) - palmitic acid , medicine , endocrinology , metabolism , fatty acid , carbohydrate metabolism , kinetics , chemistry , incubation , beta oxidation , biochemistry , physics , quantum mechanics
This study was designed to investigate the relative importance of carbohydrate and fatty acids as substrates for energy production in the urinary bladder and to obtain information about the kinetics involved in the oxidation of glucose and a representative fatty acid by rabbit bladder incubated in vitro. Isolated strips of rabbit bladder body were incubated in the presence of various concentrations of 14 C‐glucose or 14 C‐palmitate for different periods of time up to 90 minutes. The rate of 14 CO 2 generation was measured. In addition, the effect of bethanechol on both glucose and palmitic acid metabolism was determined. The results can be summarized as follows: (1) The oxidation of glucose showed a distinct lag period with time lasting for about 30 minutes. From 30 to 90 minutes the rate of 14 C 2 ‐palmitate was linear over the entire 90‐minute period of incubation. (2) Experiments in which the concentration of glucose was varied showed saturation kinetics. From a Lineweaver‐Burk plot a V max of 0.645 umol/g/hr was obtained with a k m of 2.30 mM. (3) Preincubation of tissues without substrate caused a significant increase in the rate of glucose oxidation. (4) The rate of oxidation of 14 C‐palmitate increased with concentration of the fatty acid. (5) A Lineweaver‐Burk plot showed a V max of 30.0 nmol/g/hr and a k m of 2.50 mM. Addition of unlabeled glucose to tissues oxidizing 14 C‐palmitate had no effect on 14 CO 2 production. Similarly, the addition of non‐radioactive palmitate to tissues incubated with 14 C‐glucose did not decrease glucose oxidation. When both radioactive substrates were present the rates of oxidation were additive. (6) Although bethanechol stimulated glucose oxidation, the drug had no significant effect on palmitate metabolism.