To determine the role of prolactin in increasing junctional communication among islet β-cells, we studied dye coupling in pancreatic islets exposed to elevated levels of prolactin in vivo and in vitro. Islets were isolated from rats immediately after lactation or from rats bearing mammosomatotropic tumors (MtTW15), conditions involving high levels of prolactin (either 5-fold or 1000-fold control levels, respectively). When β-cells were microinjected with the gap junction permeant dye Lucifer yellow CH, the mean number of dye-coupled cells per injection was ∼10-fold greater than in islets from virgin control rats. As a more direct test of the effects of prolactin on β-cell coupling, islets isolated from virgin rats were treated for 90 min with 500 ng/ml rat prolactin in the presence of low glucose (2.8 mM) and were microinjected with dye. The mean number of dye-coupled cells per injection increased by 6.7-fold over controls with low glucose, demonstrating a direct effect of prolactin on β-cell coupling. In vitro treatment with high glucose (16.7 mM) resulted in a 2.7-fold increase in dye-coupled cells per injection. We discuss the possible relationship between the effects of glucose and of prolactin on coupling.
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Original Contribution|
October 01 1987
Prolactin Enhances Cell-to-Cell Communication Among β-Cells in Pancreatic Islets
Robin L Michaels;
Robin L Michaels
Department of Cell Biology and Neuroanatomy, University of Minnesota
Minneapolis, Minnesota
; and the Department of Biological Chemistry, Washington University School of Medicine
St. Louis, Missouri
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Robert L Sorenson;
Robert L Sorenson
Department of Cell Biology and Neuroanatomy, University of Minnesota
Minneapolis, Minnesota
; and the Department of Biological Chemistry, Washington University School of Medicine
St. Louis, Missouri
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Jonathan A Parsons;
Jonathan A Parsons
Department of Cell Biology and Neuroanatomy, University of Minnesota
Minneapolis, Minnesota
; and the Department of Biological Chemistry, Washington University School of Medicine
St. Louis, Missouri
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Judson D Sheridan
Judson D Sheridan
Department of Cell Biology and Neuroanatomy, University of Minnesota
Minneapolis, Minnesota
; and the Department of Biological Chemistry, Washington University School of Medicine
St. Louis, Missouri
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Address correspondence and reprint requests to Dr. Judson D. Sheridan, Department of Cell Biology and Neuroanatomy, University of Minnesota, 4-135 Jackson Hall, 321 Church St., S.E., Minneapolis, MN 55455.
Diabetes 1987;36(10):1098–1103
Article history
Received:
February 05 1987
Revision Received:
April 02 1987
Accepted:
April 02 1987
PubMed:
3308580
Citation
Robin L Michaels, Robert L Sorenson, Jonathan A Parsons, Judson D Sheridan; Prolactin Enhances Cell-to-Cell Communication Among β-Cells in Pancreatic Islets. Diabetes 1 October 1987; 36 (10): 1098–1103. https://doi.org/10.2337/diab.36.10.1098
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