[15N tracer kinetics of the utilization of yeast nitrogen].
The utilization of nitrogen from 15N-labeled Saccharomyces cerevisiae cells was studied in 6 infants by means of oral pulse labeling, comparing native and heat-treated yeast cells. The 15N dose used was 3 mg/kg. The body weight of the subjects varied between 5500 and 9400 g. The yeast cells were harvested from a culture medium which contained 15N ammonium chloride as the only source of nitrogen. The 15N-enrichment of the cells amounted to 95 atom-%. In the course of 48 h following the administration of the native yeast cells, 11% of the tracer dose were renally excreted. The corresponding value after labeling with heat-treated yeast cells was 17.9%. The cumulative renal excretion of the tracer tended to be faster as compared with pulse labeling of the native yeast cells. A paired comparison with labeled native and heated yeast cells in 3 subjects did not reveal any differences in the retention rate of 15N. When untreated 15N yeast cells were administered, 13.2% of the tracer dose were excreted in the urine and 10% respectively in the faeces. The retention was 76.8%. After single pulse labeling with 3 mg 15N/kg from heat-treated yeast cells the corresponding values were 19.4%, 4.4% and 76.2%, respectively. The kinetic of the renal 15N excretion points at the partial absorption of the yeast nitrogen from the colon.
Heine
W
W
Klinik für Kinderheilkunde des Bereiches Medizin der Wilhelm-Pieck-Universität Rostock, DDR.
Klinkmann
J
J
Wutzke
K D
KD
Mix
M
M
D005243:Feces / Q000032:analysis; D006801:Humans; D007223:Infant; D007700:Kinetics; D009584:Nitrogen / Q000378:metabolism* / Q000652:urine; D009590:Nitrogen Radioisotopes; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
D009590:Nitrogen Radioisotopes; D009584:Nitrogen
15N-tracerkinetische Untersuchungen zur Utilisation von Hefestickstoff.