[Glutathione metabolism during postnatal development of the rat lung].
BACKGROUND
Significant changes in lung antioxidants occur in preparation for birth. Little is known about physiological regulation of antioxidants in the postnatal period.


OBJECTIVE
To study the glutathione system in the lungs during postnatal development.


METHODS
In the lungs of 7, 15, 21, 50 and 70 days old Sprague-Dawley rats we measured total and oxidized glutathione content as well as the activity of the limiting enzyme in glutathione synthesis (y-GCS) and of the enzymes glutathione peroxidase (GPx) and glutathione reducíase (GRd).


RESULTS
Between 7 and 15 days the activities of GPx and GRd increase 32% and 26%, respectively (p <0.001). Whereas GPx activity remains high throughout the rest of the study period, GRd activity decreases progressively reaching adulthood values at 7 days. y-GCS activity shows a gradual increase that reaches significance at 50 days when it doubles values observed at 7 days (p <0.05). A significant correlation was found between GPx and GRd activities over the entire period (r =0.62, p <0.0001). Strength of the correlation is age dependent due to the differences in time course of the enzyme changes. Whereas total GSH does not change, oxidized glutathione decreases from 7% at 7 and 15 days to 4% later on (p <0.01).


CONCLUSIONS
The activity of several enzymes involved in glutathione metabolism increases during postnatal development of the rat lung. Interpretation of lung responses to injurious agents needs to be done taking into consideration the physiological regulation of antioxidants during postnatal development.
Ramírez
Alejandro
A
Departamento de Enfermedades Respiratorias, Pontificia Universidad Católica de Chile, Santiago, Chile.
Reyes
Tatiana
T
Liberona
Leonel
L
Bustamente
Andrea
A
Sáez
Claudia
C
Borzone
Gisella
G
D000704:Analysis of Variance; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D005721:Glutamate-Cysteine Ligase / Q000378:metabolism; D005978:Glutathione / Q000096:biosynthesis / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D008168:Lung / Q000201:enzymology* / Q000254:growth & development; D008297:Male; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D000975:Antioxidants; D005979:Glutathione Peroxidase; D005980:Glutathione Reductase; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione