Abstract
The effects of dexamethasone on somatomedin- C (SM-C) stimulation of [3H]thymidine incorporation and cell replication were studied in early passage fibroblasts from normal donors, aged 7-24 yr (young) and 85-96 yr (old), and one patient with progeria. Preincubation of cells from young donors with dexamethasone dramatically enhanced SM-C stimulation of [3H]thymidine incorporation [e.g. 19- vs. 3-fold in serum-free medium; 66- vs. 14-fold in 0.25% human hypopituitary serum (HHS)], with no alteration in the timing of peak thymidine incorporation. In contrast, preincubation of cells from old and progeric donors with dexamethasone resulted in a 6- to 12-hr lengthening of the prereplicative period and, generally, little or no synergism with SM-C. Cells from old and progeric donors had a normal replicative response to SM-C with or without 0.25% HHS. In cells from young donors, dexamethasone enhanced the SM-C-stimulated increase in cell number 32%49% in serum-free medium and 70-189% in 0.25% HHS. In comparison, dexamethasone had no potentiating effect on SM-C stimulation of multiplication of cells from old and progeric donors. These data indicate that dexamethasone and SM-C are synergistic in stimulating DNA synthesis and replication of fibroblasts from young donors, but that this synergism is impaired in cells from aged and progeric donors.
Original language | English (US) |
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Pages (from-to) | 423-428 |
Number of pages | 6 |
Journal | Journal of Clinical Endocrinology and Metabolism |
Volume | 61 |
Issue number | 3 |
DOIs | |
State | Published - Sep 1985 |
Externally published | Yes |
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Biochemistry
- Endocrinology
- Clinical Biochemistry
- Biochemistry, medical