title: Reduction of urea generation and muscle protein degradation by adrenalectomy in acutely uremic rats.
abstract: The effect of adrenalectomy on the enhanced protein degradation in acute uremia was investigated. Therefore, serum urea nitrogen, urea N appearance and Nt-methylhistidine were followed in bilaterally nephrectomized rats. At 48 h after induction of uremia the animals displayed serum urea nitrogen levels of 223 +/- 9.5 mg/dl as compared to 26.0 +/- 1.0 mg/dl in sham-treated rats. This increment was significantly attenuated in acutely uremic, adrenalectomized animals (176 +/- 6.0 mg/dl). When these rats were substituted with corticosterone (5 mg/kg body weight), serum urea nitrogen readily increased to levels of acutely uremic animals with intact adrenal glands (225 +/- 6.0 mg/dl). The net generation of urea, as determined by the urea N appearance, was significantly increased during acute uremia (370 +/- 26 mg/48 h) as compared to SHAM animals (220 +/- 15 mg/48 h). This increment of urea formation could almost be completely reversed by simultaneous adrenalectomy (238 +/- 20 mg/48 h). When these rats were substituted with corticosterone, the urea N appearance rebounded to values quite comparable to acutely uremic rats with intact adrenal glands (363 +/- 30 mg/48 h). To determine whether skeletal muscle proteins might serve as a source for the enhanced protein degradation in acute uremia, plasma levels of Nt-methylhistidine were measured. Bilaterally nephrectomized rats had Nt-methylhistidine values of 9.6 +/- 1.0 micrograms/ml. In acutely uremic rats without adrenal glands, Nt-methylhistidine levels were found to be significantly decreased (6.0 +/- 0.4 micrograms/ml).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Internal Medicine, University of Würzburg, FRG.
authors.forename: R M
authors.initials: RM
authors.lastname: Schaefer
authors.forename: J
authors.initials: J
authors.lastname: Weipert
authors.forename: M
authors.initials: M
authors.lastname: Moser
authors.forename: G
authors.initials: G
authors.lastname: Peter
authors.forename: E
authors.initials: E
authors.lastname: Heidbreder
authors.forename: W H
authors.initials: WH
authors.lastname: Hörl
authors.forename: A
authors.initials: A
authors.lastname: Heidland
mesh_terms: D000208:Acute Disease; D000315:Adrenalectomy; D000818:Animals; D001806:Blood Urea Nitrogen; D005938:Glucocorticoids / Q000008:administration & dosage; D008297:Male; D008762:Methylhistidines / Q000097:blood; D009124:Muscle Proteins / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014508:Urea / Q000096:biosynthesis*; D014511:Uremia / Q000097:blood / Q000378:metabolism*
chemical_list: D005938:Glucocorticoids; D008762:Methylhistidines; D009124:Muscle Proteins; D014508:Urea