Glucocorticoid receptors and inhibition of neonatal mouse dermal fibroblast growth in primary culture

Abstract
Summary Primary cultures of dermal fibroblasts from neonatal mice were used to investigate some of the anti-inflammatory effects of glucocorticoids in vitro as influenced by the genetic background of two different strains of mice (A/J and C57 B1/6J). Fibroblasts were cultured in the absence or presence of various glucocorticoids for 2–7 days. After 4–7 days in the presence of steroid, DNA synthesis was reduced by 50–85% while protein synthesis was inhibited by 50–60%. Corticosterone produced a dose-dependent inhibition of DNA synthesis in these cells with a 50% reduction occurring at 10 nM. Specific, high affinity, low capacity binding proteins for [3H]dexamethasone or [3H]triamcinolone acetonide were identified in the cytoplasm of neonatal dermal fibroblasts which had an apparent Kd of 9 nM and ∼5,200–6,400 binding sites/cell. Sedimentation analysis of the [3H]triamcinolone acetonide-receptor complexes on low salt glycerol gradients exhibited binding in the 7 to 8 S region of the gradients. These studies demonstrate that inhibition of growth of primary cultures of mouse neonatal dermal fibroblasts by glucocorticoids is probably mediated by a receptor-mediated pathway, and that this primary culture system might be useful in delineating other anti-inflammatory effects of glucocorticoids in vitro.