Abstract
In T-cell lines lioin normal individuals transformed by the HTLV-II retrovirus, we have shown that (1) GH preincubation completely inhibits the normal insulin-induced two-peak clonal response, and (2) direct clonal stimulation of GH on T-cells is mediated via local IGF-1. In the current study, we sought determine (I) if the ability of GH preincubation to induce resistance to the mitogenic action of insulin is also mediated by IGF-1 and (2) if a Pyymy T-cell line (previously shown to be both GH- and IGF-1-resistant in direct stimulation assays) would or would not become insulin-resistant following either GH or IGF-1 preincubation. T-cell lines from 3 normals and I Pygmy were studied. Colony formation was assessed in response to insulin (a) alone (1.2-13.2 × 103 pmol/L), following 2 hr preincubalion with either (b) GH (50 μg/L) or (c) IGF-1 (8 μg/L), and (d) following 1 hr preincubation willi αIR3, a monoclonal antibidy against the IGf-1 receptor, and then 2 hr with GH. The following mean (±SE) refuses (first peak/second peak) were noted (*p<0.001 vs insulin alone):
These daia indicate that, in normal T-cell lines, either (b) GH or (c) IGF-1 preincubation induces resistance to insulin-induced clonogenesis. Since, in normals, GH-induced insulin resistance can be blocked by preincubation with αIR3 (d), this action of GH must be mediated through a local IGF-1 loop. Therefore, in the Pygmy T-cell line, since there was no significant reduction in insulin responsiveness following either GH or IGF-1 preincubation, the data suggest that the ygmy is IGF-1-resistant and support our earlier findings of resistance to the direct stimulatory effects of GH and IGF-1.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Geffner, M., Bersch, N., Bailey, R. et al. GH PREINCUBATION FAILS TO INDUCE RESISTANCE TO THE MITOGCNIC ACTION OF INSULIN IN A PYGMY T-CELL LINE. Pediatr Res 33 (Suppl 5), S67 (1993). https://doi.org/10.1203/00006450-199305001-00382
Issue Date:
DOI: https://doi.org/10.1203/00006450-199305001-00382