Comparison of STAT5 mRNA levels in GH-treated male and female rats analysed by a solution hybridization assay

In this study we describe the development of a RNA:RNA solution hybridizati on-RNase protection assay to quantify STAT5 mRNA in total RNA extracts from rat tissues. The assay is sensitive and reproducible. We quantified STAT5 mRNA levels in liver and thymus lymphocytes from male and female control ra ts and from rats treated with a single dose of recombinant human growth hor mone (rhGH). No significant sex differences in the expression pattern were observed in both studied tissues, but STAT5 mRNA levels were significantly (P< 0.05) higher in liver than in thymus lymphocytes. STAT5 mRNA levels wer e significantly (P< 0.05) increased by a pulse of GH given to either male o r female normal rats, suggesting a regulation of STAT5 gene expression in t he studied tissues. In conclusion, quantitative solution hybridization-RNas e protection assay of STAT5 mRNA provides a tool to further advance the stu dy of the regulatory mechanisms involved in STAT5 gene expression. (C) 2000 Harcourt Publishers Ltd.