Abstract
Chronic hyperglycemia and hyperinsulinemia have recently been shown to increase glycogen and decrease alveolar surfactant in fetal lamb lung. Since cAMP regulates lung energy metabolism and surfactant release, we postulated that chronic hyperglycemia and hyperinsulinemia would alter cAMP metabolism of fetal lamb lung. Infusion of glucose into 6 chronically catheterised fetal lambs between 112 and 143d. gestation increased serum glucose 2 fold and serum insulin 3 fold compared to twin controls. Adenylate cyclase activity increased 105% in the glucose treated v. controls, 6.71±0.16 v. 3.27±0.18 pmoles cAMP/min/mg lung, (P< 0.001) and lung cAMP content increased 111% in the glucose-treated v. controls, 0.76 to .19 v. 0.3610.02 pmole/mg lung, (P < 0.001). However, lung cAMP dependent protein kinase (PK) activity decreased 40% in the glucose-treated v. controls, 135.5±5.6 v. 225.5±4.1 pmole/min/ mg supernatant protein (P < 0.001), while the ratio of non-cAMP PK to cAMP PK was similar (P > 0.05) in both groups (0.34±0.02 v. 0.38±0.02). These data show that chronic hyperglycemia and hyperinsulinemia influence energy metabolism in fetal lamb lung. Accumulation of cAMP may be attributed to increased cAMP production by adenylate cyclase. But decreased cAMP PK activity may be an important control point in the inhibition of fetal lung maturation by chronic hyperglycemia and hyperinsulinemia.
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Warburton, D. 329 CHRONIC HYPERGLYCEMIA AND HYPERINSULINEMIA REDUCE cAMP DEPENDENT PROTEIN KINASE ACTIVITY IN FETAL LAMB LUNG. Pediatr Res 19, 165 (1985). https://doi.org/10.1203/00006450-198504000-00359
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DOI: https://doi.org/10.1203/00006450-198504000-00359