Expression and localization of prolactin messenger ribonucleic acid in the human immune system.

Abstract

Pituitary PRL is involved in immunoregulation. Also, a PRL-like molecule is secreted by peripheral blood mononuclear cells. In this study, we examined tissues of the human immune system to evaluate if the PRL gene is expressed and to determine the location and type of cells involved in its synthesis. To evaluate the expression of PRL messenger RNA (mRNA) in normal and abnormal human lymphoid tissues, we used RT-PCR to generate a specific 276-bp product from normal human thymus, spleen, tonsil, lymph node, and lymphoid tumors. Restriction enzyme digestion confirmed that this PCR product was expressed PRL. Furthermore, we developed a specific and sensitive nonisotopic in situ hybridization technique for PRL mRNA, and cells containing PRL mRNA were found in each tissue of the human immune system. Also, PRL mRNA was widely distributed throughout neoplastic tissue from a thymoma and lymphomas where mitogenic and anti-apoptotic properties of PRL could be involved in tumor progression. PRL mRNA was localized in lymphocytes, epithelial cells, and vascular endothelial cells. The presence of PRL mRNA in vascular endothelium cells suggests other roles for PRL in these tissues in addition to immunomodulation. In conclusion, the presence of PRL mRNA in human lymphoid tissue implies that locally synthesized PRL may play a critical role in immunocompetence by providing an important regulatory signal to the microenvironment of human lymphoid organs.

Extrapituitary Expression of the Prolactin Gene in the Goldfish, African Clawed Frog and Mouse

“…Together with these data, the present result suggests that the tissue distribution of PRL diverged in the teleosts. Unlike the results previously reported for humans (Wu et al, 1996) and rats (Shaw-Bruha et al, 1998), PRL was not detected in the spleen of the mouse in this study. This discrepancy may be due to differences in experimental conditions, such as the immunological status of the animals or the number of PCR cycles.…”

Big Prolactin 60 kDa is Overexpressed in Salivary Glandular Epithelial Cells from Patients with Sjögren's Syndrome

“…In our study the cell types expressing big prolactin in SS patients is different. Why there is such a difference in the tissue expression is not known, but big prolactin expression has previously been observed in activated peripheral blood mononuclear cells (Sabhrawal et al, 1992), as well as in vascular and epithelial tissues (Wu et al, 1996). More interesting is the close genomic linkage between HLA alleles and the prolactin gene.…”

Chronic stress down-regulates growth hormone gene expression in peripheral blood mononuclear cells of older adults

“…For example, peripheral blood mononuclear cells (PBMCs) can secrete growth hormone (GH) and prolactin (Weigent and Blalock, 1990;Sabharwal et al, 1992a;Varma et al, 1993;Hattori et al, 1994) and GH mRNA and PRL mRNA can be localized in each tissue of the human immune system (Wu et al, 1995;Wu et al, 1996).…”