GROWTH-HORMONE AND PIT-1 EXPRESSION IN BOVINE FETAL LYMPHOID-CELLS

Bovine fetal lymphoid cells were examined for growth hormone (GH) and the transcription factor Pit-1/GHF-1 mRNA. GH and Pit-1/GHF-1 transcri pts were detected in thymocytes and splenocytes from fetuses at 60, 90 , 120, and 270 d of gestation using reverse transcription-polymerase c hain reaction (RT-PCR). Northern analysis indicated that the lymphoid GH mRNA was approximately 350 nucleotides larger than in the pituitary . RT-PCR analysis demonstrated that the coding regions as well as 3' u ntranslated regions of the lymphocyte GH and pituitary transcripts wer e the same. Analysis of the 5'-untranslated region of the lymphocyte G H mRNA showed that transcription began upstream from the start site in the pituitary gland, suggesting differences in regulation in these ti ssues. Fetal thymocytes and splenocytes expressed Pit-1/GHF-1 mRNA; ho wever, they contained only the 2.5-kb transcript. The GH and Pit-1/GHF -1 mRNA in fetal lymphoid cells supports the hypothesis that lymphocyt e-derived GH may function as an autocrine and/or paracrine factor duri ng the development and maturation of the bovine fetal immune system. ( C) Elsevier Science Inc. 1997.