J Korean Soc Ther Radiol.  1997 Sep;15(3):197-206.

Alteration of Phospholipase D Activity in the Rat Tissues by Irradiation

• Choi MS
• Cho YJ
• Choi MU

Abstract

PURPOSE
Phospholipase D (PLD) catalyzes the hydrolysis of phosphatidyl choline to phosphatidic acid (PA) and choline. Recently, PLD has been drawing much attentions and considered to be associated with cancer process since it is involved in cellular signal transduction. In this experiment, oleate-PLD activities were measured in various tissues of the living rats after whole body irradiation. MATERIAL AND METHODS: The reaction mixture for the PLD assay contained 0.1microCi 1,2-di[1-14C]palmitoyl phosphatidylcholine, 0.5mM phosphatidylcholine, 5mM sodium oleate, 0.2% taurodeoxycholate, 50mM HEPES buffer (pH 6.5), 10mM CaCl2, and 25mM KF. phosphatidic acid, the reaction product, was separated by TLC and its radioactivity was measured with a scintillation counter. The whole body irradiation was given to the female Wistar rats via Cobalt 60 Teletherapy with field size of 10cm x 10cm and an exposure of 2.7Gy per minute to the total doses of 10Gy and 25Gy.
RESULTS
Among the tissues examined, PLD activity in lung was the highest one and was followed by kidney, skeletal muscle, brain, spleen, bone marrow, thymus, and liver. Upon irradiation, alteration of PLD activity was observed in thymus, spleen, lung, and bone marrow. Especially PLD activities of the spleen and thymus revealed the highest sensitivity toward gamma-ray with more than two times amplification in their activities. In contrast, the PLD activity of bone marrow appears to be reduced to nearly 30%. Irradiation effect was hardly detected in liver which showed the lowest PLD activity.
CONCLUSION
The PLD activities affected most sensitively by the whole-body irradiation seem to be associated with organs involved in immunity and hematopoiesis. This observation strongly indicates that the PLD is closely related to the physiological function of these organs. Furthermore, radiation stress could offer an important means to explore the phenomena covering from cell proliferation to cell death on these organs.

Keyword

Phospholipase D; Whole-body irradiation; Radiation effect; Thymus; Spleen

MeSH Terms

Animals
Attention
Bone Marrow
Brain
Cell Death
Cell Proliferation
Choline
Cobalt
Female
Hematopoiesis
HEPES
Humans
Hydrolysis
Kidney
Liver
Lung
Muscle, Skeletal
Oleic Acid
Phosphatidic Acids
Phosphatidylcholines
Phospholipase D*
Phospholipases*
Radiation Effects
Radioactivity
Rats*
Rats, Wistar
Scintillation Counting
Signal Transduction
Sodium
Spleen
Taurodeoxycholic Acid
Thymus Gland
Whole-Body Irradiation
Choline
Cobalt
HEPES
Oleic Acid
Phosphatidic Acids
Phosphatidylcholines
Phospholipase D
Phospholipases
Sodium
Taurodeoxycholic Acid