Perinatal development of pulmonary antioxidant defences
Perinatal development of pulmonary antioxidant defences
The development of the pulmonary antioxidant defences was investigated during fetal and neonatal development in the guinea pig. Lung catalase and copper/zinc superoxide dismutase (Cu/Zn-SOD) activities increased continuously from day 50 gestation to 10 days after term (day 68) but then decreased again by adulthood. Mean lung glutathione peroxidase (GSH-Px) and manganese superoxide dismutase (Mn-SOD) activities increased to a peak at term and then decreased post-term. After birth, Mn-SOD activity increased considerably into adulthood. Lung glutathione (GSH) did not change greatly throughout the period studied. Lung dipalmityl phosphatidylcholine (DPPC) increased 13 fold in the last 18 days of gestation. It was concluded that if delivered prematurely, this species would be deficient in lung catalase, Cu/Zn-SOD and DPPC. Liver Mn-SOD, Cu/Zn-SOD, GSH-Px, catalase and GSH all increased in the last part of gestation and again following birth. A similar pattern was also seen with kidney Mn-SOD, Cu/Zn-SOD, GSH-Px and catalase. These changes seemed to mirror the functional (ie. metabolic) activity of these tissues. No age realated difference in tolerance to exposure to hyperoxia (95%) between -3 and + 5 days of age was observed although the older animals were slightly more susceptible. Exposure to hyperoxia (85%) for 72 hours elicited increases in lung activities of Mn-SOD, GSH-Px and catalase in premature animals but in the past term animals, only Mn-SOD responded significantly. This exposure had no effect on lung Cu/Zn-SOD activity of DPPC in either age group. Treating pregnant guinea pigs with metyrapone, a glucocorticoid synthesis inhibitor, had no effect on fetal lung antioxidant enzymes. Use of the glucocorticoid agonist RU2862 in Zucker rats severely restricted post-term development of Cu/Zn-SOD, GSH-Px and catalase while accelerating pulmonary surfactant development, suggesting that the development of the lung surfactant is regulated in a different manner by glucocorticoids from that of the antioxidant enzymes.
University of Southampton
Rickett, Guy Masami Wilson
1991
Rickett, Guy Masami Wilson
Rickett, Guy Masami Wilson
(1991)
Perinatal development of pulmonary antioxidant defences.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The development of the pulmonary antioxidant defences was investigated during fetal and neonatal development in the guinea pig. Lung catalase and copper/zinc superoxide dismutase (Cu/Zn-SOD) activities increased continuously from day 50 gestation to 10 days after term (day 68) but then decreased again by adulthood. Mean lung glutathione peroxidase (GSH-Px) and manganese superoxide dismutase (Mn-SOD) activities increased to a peak at term and then decreased post-term. After birth, Mn-SOD activity increased considerably into adulthood. Lung glutathione (GSH) did not change greatly throughout the period studied. Lung dipalmityl phosphatidylcholine (DPPC) increased 13 fold in the last 18 days of gestation. It was concluded that if delivered prematurely, this species would be deficient in lung catalase, Cu/Zn-SOD and DPPC. Liver Mn-SOD, Cu/Zn-SOD, GSH-Px, catalase and GSH all increased in the last part of gestation and again following birth. A similar pattern was also seen with kidney Mn-SOD, Cu/Zn-SOD, GSH-Px and catalase. These changes seemed to mirror the functional (ie. metabolic) activity of these tissues. No age realated difference in tolerance to exposure to hyperoxia (95%) between -3 and + 5 days of age was observed although the older animals were slightly more susceptible. Exposure to hyperoxia (85%) for 72 hours elicited increases in lung activities of Mn-SOD, GSH-Px and catalase in premature animals but in the past term animals, only Mn-SOD responded significantly. This exposure had no effect on lung Cu/Zn-SOD activity of DPPC in either age group. Treating pregnant guinea pigs with metyrapone, a glucocorticoid synthesis inhibitor, had no effect on fetal lung antioxidant enzymes. Use of the glucocorticoid agonist RU2862 in Zucker rats severely restricted post-term development of Cu/Zn-SOD, GSH-Px and catalase while accelerating pulmonary surfactant development, suggesting that the development of the lung surfactant is regulated in a different manner by glucocorticoids from that of the antioxidant enzymes.
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Published date: 1991
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Local EPrints ID: 460915
URI: http://eprints.soton.ac.uk/id/eprint/460915
PURE UUID: bbd1bda0-33a6-47f7-8416-a13f82143f1a
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Date deposited: 04 Jul 2022 18:32
Last modified: 04 Jul 2022 18:32
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Author:
Guy Masami Wilson Rickett
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