THE METABOLISM AND FATE OF TRITIATED THYMIDINE IN MAN
The metabolism and fate of tritiated thymidine were studied in two patients in hemopoietic equilibrium. Plasma clearance of H/sup 3/-thymidine commences in the first circulation time and becomes exponential following apparent equilibrium with total body water. Two components with halftimes of 0.2 minute and 1.0 minute were identified and discussed. The rapid plasma clearance of H/sup 3/-thymidine was associated with incorporation of this compound into newly formed DNA of proliferating cells as early as one minute after injection. Labeling of proliferative cells of the bone marrow was nearly complete within ten minutes after injection, and thereafter the label appeared to remain in these cells or their progeny for their life span, diluted only by successive mitoses. This short availability time of intravenous H/sup 3/-thymidine simplifies the analyses of the time parameters of labeled proliferating cell populations. About one-third of the H/sup 3/-thymidine was catabolized to THO within a few hours after injection. Small amounts of urine nonvolatile H/sup 3/ activity were excreted in the urine during the first day after injection. H/sup 3/- beta aminoisobutyric acid was identified in these urines as a catabolic product of H/ sup 3/-thymidine. Degradation and possible reutilization of the H/sup 3/ label is discussed. Severe malnutrition resulted in greater degradation of H/sup 3/ thymidine to THO and urine nonvolatile H/sup 3/ activity. (auth)
- Research Organization:
- Brookhaven National Lab., Upton, N.Y.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-14-015504
- OSTI ID:
- 4166905
- Journal Information:
- Journal of Clinical Investigation (U.S.), Journal Name: Journal of Clinical Investigation (U.S.) Vol. Vol: 39; ISSN JCINA
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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