Serum glucocorticoids have persistent and controlling effects on insulinlike growth factor i action under serum-free assay conditions in cultured human fibroblasts

Cheryl A. Conover, Ron G. Rosenfeld, Raymond L. Hintz

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

The biological actions of insulinlike growth factor I (IGF-I) measured under serum-free assay conditions were found to be significantly influenced by prior subculture conditions for adult human fibroblasts. Glucocorticoids seemed to be the major medium variable affecting IGF-I action. IGF-I added to serum-free cultures had little or no effect on [14C]aminoisobutyric acid uptake or [3H]thymidine incorporation in human fibroblasts previously maintained in media containing serum with low glucocorticoid levels or in serum stripped of endogenous steroids. However, a 48-h preincubation with dexamethasone resulted in a marked synergistic increase in IGF-I stimulation of [14C]aminoisobutyric acid uptake and [3Hthymidine incorporation in these cultures. In contrast, IGF-I in serum-free medium seemed to be a potent mitogenic and metabolic stimulus for human fibroblasts which had been subcultured in media with a high glucocorticoid content, either endogenous, or supplemented. After these culture conditions, a 48-h preexposure to dexamethasone had no further enhancing effect on IGF-I action. Dexamethasone also potentiated IGF-I, insulin, and epidermal growth factor stimulation of fibroblast replication depending on the earlier subcultivation conditions. Thus, glucocorticoids are important modulators of IGF-I bioactivity in cultured human fibroblasts. Serum glucocorticoids can exert a profound influence on the biological phenomena measured in cell culture, even when the serum has been removed before the actual experiment, and must be carefully taken into account for accurate evaluation of the biological function of IGF-I and other growth factors.

Original languageEnglish (US)
Pages (from-to)521-527
Number of pages7
JournalIn Vitro Cellular & Developmental Biology
Volume25
Issue number6
DOIs
StatePublished - Jun 1989

Keywords

  • dexamethasone
  • glucocorticoids
  • growth regulation
  • human fibroblasts
  • insulinlike growth factor I
  • serum

ASJC Scopus subject areas

  • Developmental Biology
  • Clinical Biochemistry
  • Cell Biology

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