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EXPERIMENTS CONCERNING THE RENAL CLEARANCES OF SOME FRUCTOSANS IN THE DOG
Author(s) -
Beattie J.,
Bell D. J.
Publication year - 1953
Publication title -
quarterly journal of experimental physiology and cognate medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0033-5541
DOI - 10.1113/expphysiol.1953.sp001002
Subject(s) - chemistry , kidney , vasomotor , polymer , homogeneous , medicine , endocrinology , biochemistry , organic chemistry , physics , thermodynamics
1. In continuance of previous work, experiments have been carried out on the renal clearance in the female dog of certain fructosans, namely ( a ) irisin isolated from Iris pseudacorus , and ( b ) and ( c ) the high molecular weight levans synthesised respectively by exocellular enzyme systems of Ps. prunicola and B. subtilis. 2. From the pattern of the renal clearances over a period of up to three hours, it seems clear that while irisin and Ps. prunicola levan may be, by present standards, chemically homogeneous, they are, in fact, physically heterogeneous, i.e. each consists of an assembly of similarly constituted polymers. 3. While intravenous administration of low molecular weight grass levan and irisin is unaccompanied by vasomotor and respiratory disturbances, the higher molecular weight bacterial levans, despite vigorous measures to remove any traces of alkali‐hydrolysable material ( e.g. protein), induced such disturbances. B. subtilis levan produced more intense responses than did Ps. prunicola levan. 4. Ps. prunicola levan is presumed to be a “very large molecule”. Its extremely low clearance by the kidney indicates that the components of the assembly of molecules in the material pass through the renal glomerular membrane only with great difficulty and are not hydrolysed to any appreciable extent within the animal body. 5. B. subtilis levan, which from chemical evidence can be considered to be a polymer of similar chemical units to those comprising Ps. prunicola levan, behaved in a markedly different manner. The high clearance values were not those to be expected from a high molecular weight fructosan. The discovery of considerable quantities of D‐fructose in the urine after injection with this levan indicated that the dog is able to hydrolyse this levan at a rapid rate. The rate of liberation of fructose was so rapid that it exceeded the rate of utilisation in the tissues and/or absorbtion of fructose by the kidney. D‐fructose was identified by ( a) paper chromatography, and ( b ) the formation of the methylphenyl osazone and its acetyl derivative.