Endocrinology, Vol 121, 1447-1453, Copyright © 1987 by Endocrine Society

ARTICLES

Prolactin (in vitro) decreases the glucose stimulation threshold, enhances insulin secretion, and increases dye coupling among islet B cells

RL Sorenson, TC Brelje, OD Hegre, S Marshall, P Anaya and JD Sheridan
Department of Cell Biology and Neuroanatomy, University of Minnesota, Minneapolis 55455.

The purpose of this study was to determine the in vitro effect of ovine PRL (oPRL) on the dynamics of insulin secretion and dye coupling among islet B cells. The effect of oPRL (2 micrograms/ml) on insulin secretion was time dependent and reached a maximum on day 4 when there was a 2.4-fold increase in insulin secretion from cultured neonatal rat islets (n = 6, P less than 0.001). When islets cultured in the presence of oPRL for 4 days were perifused, 300 mg/dl glucose stimulation resulted in insulin release of 131 +/- 20 microU/ml.100 micrograms islet tissue as compared to control islets 94 +/- 20 microU/ml.100 micrograms islet tissue (n = 7, P less than 0.02). Stimulation of the islets with a linear 30-250 mg/dl glucose gradient resulted in a threshold for glucose-stimulated insulin secretion of 73 +/- 6 mg/dl glucose for the oPRL treated islets (n = 7) as compared to a threshold of 123 +/- 6 mg/dl glucose for control islets (n = 7, P less than 0.001). Mean islet volume was unchanged after 4 days of oPRL treatment but was 34% greater after 8 days (n = 6, P less than 0.001). Dye coupling among central islet B cells was also increased after in vitro treatment with oPRL for 4 days. The mean projected area of dye spread was 2-fold greater in the oPRL treated islets (n = 33) in comparison to the control islets (n = 33, P less than 0.05). These results indicate that in vitro lactogen treatment, in the form of oPRL, alters insulin secretory behavior and B cell junctional communication and supports our hypothesis that lactogen, insulin secretion, and junctional communication among B cells are related.

This article has been cited by other articles:

				M. Salehi, B. A. Aulinger, and D. A. D'Alessio Targeting {beta}-Cell Mass in Type 2 Diabetes: Promise and Limitations of New Drugs Based on Incretins Endocr. Rev., May 1, 2008; 29(3): 367 - 379. [Abstract] [Full Text] [PDF]

				M. J. LeBaron, T. J. Ahonen, M. T. Nevalainen, and H. Rui In Vivo Response-Based Identification of Direct Hormone Target Cell Populations Using High-Density Tissue Arrays Endocrinology, March 1, 2007; 148(3): 989 - 1008. [Abstract] [Full Text] [PDF]

				C. R. LaPensee, N. D. Horseman, P. Tso, T. D. Brandebourg, E. R. Hugo, and N. Ben-Jonathan The Prolactin-Deficient Mouse Has an Unaltered Metabolic Phenotype Endocrinology, October 1, 2006; 147(10): 4638 - 4645. [Abstract] [Full Text] [PDF]

				M. Johansson, G. Mattsson, A. Andersson, L. Jansson, and P.-O. Carlsson Islet Endothelial Cells and Pancreatic {beta}-Cell Proliferation: Studies in Vitro and during Pregnancy in Adult Rats Endocrinology, May 1, 2006; 147(5): 2315 - 2324. [Abstract] [Full Text] [PDF]

				C Ortega-Gonzalez, L Cardoza, B Coutino, R Hidalgo, G Arteaga-Troncoso, and A Parra Insulin sensitizing drugs increase the endogenous dopaminergic tone in obese insulin-resistant women with polycystic ovary syndrome J. Endocrinol., January 1, 2005; 184(1): 233 - 239. [Abstract] [Full Text] [PDF]

				J. Shao, L. Qiao, and J. E. Friedman Prolactin, progesterone, and dexamethasone coordinately and adversely regulate glucokinase and cAMP/PDE cascades in MIN6 {beta}-cells Am J Physiol Endocrinol Metab, February 1, 2004; 286(2): E304 - E310. [Abstract] [Full Text] [PDF]

				A. J. Weinhaus, N. V. Bhagroo, T. C. Brelje, and R. L. Sorenson Dexamethasone Counteracts the Effect of Prolactin on Islet Function: Implications for Islet Regulation in Late Pregnancy Endocrinology, April 1, 2000; 141(4): 1384 - 1393. [Abstract] [Full Text] [PDF]

				E. D. Galsgaard, J. H. Nielsen, and A. Moldrup Regulation of Prolactin Receptor (PRLR) Gene Expression in Insulin-producing Cells. PROLACTIN AND GROWTH HORMONE ACTIVATE ONE OF THE RAT PRLR GENE PROMOTERS VIA STAT5a AND STAT5b J. Biol. Chem., June 25, 1999; 274(26): 18686 - 18692. [Abstract] [Full Text] [PDF]

				C. Bole-Feysot, V. Goffin, M. Edery, N. Binart, and P. A. Kelly Prolactin (PRL) and Its Receptor: Actions, Signal Transduction Pathways and Phenotypes Observed in PRL Receptor Knockout Mice Endocr. Rev., June 1, 1998; 19(3): 225 - 268. [Abstract] [Full Text]

				C. Carlsson, D. Tornehave, K. Lindberg, P. Galante, N. Billestrup, B. Michelsen, L.-I. Larsson, and J. H. Nielsen Growth Hormone and Prolactin Stimulate the Expression of Rat Preadipocyte Factor-1/{Delta}-Like Protein in Pancreatic Islets: Molecular Cloning and Expression Pattern during Development and Growth of the Endocrine Pancreas Endocrinology, September 1, 1997; 138(9): 3940 - 3948. [Abstract] [Full Text] [PDF]

				L. E. Stout, A. M. Svensson, and R. L. Sorenson Prolactin Regulation of Islet-Derived INS-1 Cells: Characteristics and Immunocytochemical Analysis of STAT5 Translocation Endocrinology, April 1, 1997; 138(4): 1592 - 1603. [Abstract] [Full Text] [PDF]

				J. J. Berlanga, O. Gualillo, H. Buteau, M. Applanat, P. A. Kelly, and M. Edery Prolactin Activates Tyrosyl Phosphorylation of Insulin Receptor Substrate 1and Phosphatidylinositol-3-OH Kinase J. Biol. Chem., January 24, 1997; 272(4): 2050 - 2052. [Abstract] [Full Text] [PDF]