Changes in the urinary excretion of acid-soluble peptides in rats injected with streptozotocin or dexamethasone: a trial to estimate the changes in the rate of whole-body protein degradation in those rats.
Urinary excretion of acid-soluble peptides (ASP) was measured in rats given streptozotocin or dexamethasone. Streptozotocin-induced diabetic rats excreted increased amounts of urinary nitrogen and ASP-form amino acids. The urinary ratio for N:ASP-form leucine plus valine, which has been shown to reflect the efficiency of dietary N utilization, increased in the diabetic rats, suggesting the impaired utilization of dietary N (and re-utilization of endogenous N). Dexamethasone administration to adrenalectomized rats caused increased excretion of urinary ASP-form leucine plus valine with a concomitant increase in N excretion. However, urinary ratio for N:ASP-form leucine plus valine did not change significantly. The results suggested that dexamethasone caused increased degradation of body proteins, but maintained the efficiency of dietary N utilization or re-utilization of endogenous N. Based on the present observations and the hypothesis proposed previously by the present authors (Noguchi et al. 1988) that urinary excretion of ASP-form leucine plus valine reflects the rate of whole-body protein degradation and the urinary ratio for N:ASP-form leucine plus valine represents N utilization, the origin of urinary N in streptozotocin-diabetic and dexamethasone-administered rats is discussed.
Nam
T J
TJ
Department of Agricultural Chemistry, Faculty of Agriculture, University of Tokyo, Japan.
Noguchi
T
T
Naito
H
H
D000315:Adrenalectomy; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D003907:Dexamethasone / Q000494:pharmacology*; D003921:Diabetes Mellitus, Experimental / Q000652:urine; D004044:Dietary Proteins / Q000378:metabolism; D007930:Leucine / Q000652:urine; D008297:Male; D009584:Nitrogen / Q000652:urine; D010455:Peptides / Q000652:urine*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013311:Streptozocin / Q000494:pharmacology*; D014633:Valine / Q000652:urine
D001786:Blood Glucose; D004044:Dietary Proteins; D010455:Peptides; D011506:Proteins; D013311:Streptozocin; D003907:Dexamethasone; D007930:Leucine; D014633:Valine; D009584:Nitrogen