EFFECT OF IONIZING RADIATION ON THE PYRIDINE NUCLEOTIDES OF THYMOCYTES

Journal Article · Tue Jan 01 04:00:00 EST 1963 · Biochemistry and Cell Biology

DOI:https://doi.org/10.1139/o63-166· OSTI ID:4716437

Scaife, J. F.

The pyridine nucleotides of thymocytes were examined following irradiation of the cells in vivo or in vitro. Nicotinamide-adenine dinucleotide (NAD) was found to constitute about 95% of the total oxidized pyridine nucleotides in thymocytes while the level of NADH₂ was found to be very low. There is a rapid loss of NAD from thymocytes following irradiation in vitro or in vivo which is evident with as little as 25 rads. There is no concomitant rise in the NADH₂ levels following irradiation. The ioss of NAD occurs principally from the nucleus of the cell and is characterized by an intracellular release of NADase from the mitochondria and nucleus into the cytoplasm. Following irradiation there is a reduced capacity for thymocytes to synthesize NAD from 7-C¹⁴-nicotinamide either in vitro or in vivo. The administration or presence of nicotinamide produces an unphysiologicai increase in the level of NAD in whole thymus or thymocytes in suspension. The level of NAD in treated cells is higher than in untreated controls following irradiation. This effect is not produced by nicotinic acid, cysteamine, L-cysteine, or promethazine. The administration of nicotinamide does not prevent the development of pyknotic degeneration in irradiated thymocytes. There is no change in the RNA content of the thymus under the conditions which reduce the NAD content. (auth)

• Research Organization: Defence Research Chemical Labs., Ottawa
• Sponsoring Organization: USDOE
• NSA Number: NSA-17-027085
• OSTI ID: 4716437
• Report Number(s): DRCL-402
• Journal Information: Biochemistry and Cell Biology, Journal Name: Biochemistry and Cell Biology Journal Issue: 6 Vol. 41; ISSN 0829-8211
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ALKALOIDS
AMIDES
AMINES
ANIMAL CELLS
BIOCHEMISTRY
BIOLOGY AND MEDICINE
CARBON 14
CYSTEAMINE
CYSTEINE
CYTOLOGY
ENZYMES
HETEROCYCLICS
METHYL RADICALS
MITOCHONDRIA
NICOTINE
NUCLEIC ACIDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PHENOTHIAZINES
PROPYL RADICALS
QUANTITY RATIO
RADIATION DOSES
RADIATION EFFECTS
RIBONUCLEIC ACID
THYMUS
TRACER TECHNIQUES