Korean J Anat.  1999 Apr;32(2):245-252.

Expression of Guanine Deaminase in the Developing Rat Brain

• Lee KH
• Choi JS
• Lee HY
• Shin DH
• Kang TC
• Kim HJ
• Cho SS
• Baik SH
• Seong YS
• Park JB

Abstract

Guanine aminohydrolase (GAH; Guanine deaminase, EC 3.5.4.3) is an enzyme that has a role in purine catabolism. This enzyme produces xanthine and ammonia by hydrolysis of guanine, and xanthine is further degraded to uric acid and hydrogen peroxide by another enzyme, xanthine oxidase. Most of the enzymes involved in purine catabolism have been studied for their biological functions, physiological roles and amino acid sequences, and biochemical activity of GAH is known to be detected in various organs such as liver, kidney, small intestine and brain. Its activity is also known to be changed during brain development. In this study, we hoped to reveal expression pattern of GAH in developing rat brain by western blotting and immunohistochemistry. In western blotting, GAH immunoreactivity was not detected on 14-, 16- and 18-days-old fetal rat brains. Its reactivity was first detected from 20-days-old fetal rat brain and highly increased after birth. And it was maintained at steady level from 2 weeks after birth. In immunohistochemistry, no positive cells were found on 14- and 16-days-old fetal rat brain sections. A few GAH-immunoreactive cells appeared from 18-days-old fetal rat brain and they were localized at olfactory bulb, cerebral cortex, midbrain, pons and medulla. The 20-days-old fetal rat brain also showed immunoreactive cells at hippocampus and the staining intensity was still weak. Postnatal 2-days-old rat brain also showed immunoreactive cells at basal ganglia and the number of positive cells and staining intensity were increased. Thereafter, immunoreactivity appeared on many neuronal cells around various areas in the brain and nerve fibers also showed reactivity on postnatal brains. The number of positive cells decreased from 1 week after birth and a few positive cells were observed on olfactory bulb and cerebellum from 2 weeks after birth. In mature brain most of GAH were localized on nerve fibers and few positive cells could be found on olfatory bulb only. From these, we can suspect that GAH may have some functional relationship with nerve fibers.

Keyword

guanine aminohydrolase; immunohistochemistry; western blotting; development; brai; rat

MeSH Terms

Amino Acid Sequence
Ammonia
Animals
Basal Ganglia
Blotting, Western
Brain*
Cerebellum
Cerebral Cortex
Guanine Deaminase*
Guanine*
Hippocampus
Hope
Hydrogen Peroxide
Hydrolysis
Immunohistochemistry
Intestine, Small
Kidney
Liver
Mesencephalon
Metabolism
Nerve Fibers
Neurons
Olfactory Bulb
Parturition
Pons
Rats*
Uric Acid
Xanthine
Xanthine Oxidase
Ammonia
Guanine
Guanine Deaminase
Hydrogen Peroxide
Uric Acid
Xanthine
Xanthine Oxidase