Abstract
The effects of high glucose and insulin concentrations on fetal lung insulin receptors and tyrosine kinase activity were studied in an in vitro system utilizing 19- or 20-d fetal rat lung explants. Exposure of the explants to 100 mM glucose and insulin (0.1 unit/mL) for 72 h resulted in a significant decrease in specific binding of insulin to partially purified receptors [5.78% ± 0.66 (SEM) vs. 9.64% ± 1.68; P <.01] when compared with lung explants exposed to 10 mM glucose alone. When individual effects of high insulin and glucose were studied, down-regulation of specific insulin binding was also observed, but to a lesser extent than that observed using both high glucose and insulin. Differences in insulin receptor affinity were not noted. Insulin receptor tyrosine kinase activity was also significantly decreased (52% of control values) under high-glucose/high-insulin conditions. Total phosphatidylcholine and disaturated phosphatidylcholine concentrations were significantly decreased in explants grown under high-glucose/high-insulin conditions, consistent with delayed pulmonary maturation. High glucose and insulin levels thus result in down-regulation of fetal lung insulin receptors and insulin receptor tyrosine kinase activity late in gestation. These results may have implications for substrate availability in the developing fetal lung.
Original language | English |
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Pages (from-to) | 247-258 |
Number of pages | 12 |
Journal | Experimental Lung Research |
Volume | 18 |
Issue number | 2 |
DOIs | |
State | Published - 1 Jan 1992 |
Externally published | Yes |
ASJC Scopus subject areas
- Molecular Biology
- Pulmonary and Respiratory Medicine
- Clinical Biochemistry