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Constitutive expression of placental lactogen in pancreatic beta cells: effects on cell morphology, growth, and gene expression.

Publication ,  Journal Article
Fleenor, D; Petryk, A; Driscoll, P; Freemark, M
Published in: Pediatr Res
January 2000

To explore the roles of lactogens in islet function, we generated a stable line of rat insulinoma (INS-1) cells that express rat placental lactogen II (rPLII) constitutively in culture. We used this cell line (Ins-rPLII) to examine the effects of endogenous rPLII on beta-cell growth, islet formation, and the expression of glucose transporter 2 (glut-2) and insulin mRNA. Growth and maturation of Ins-rPLII cells were compared with that of cells transfected stably with an empty expression plasmid (control) and of INS-1 cells treated with exogenous prolactin. The Ins-rPLII cells proliferated more rapidly than control cells in serumfree medium and showed distinct morphologic characteristics in culture. Whereas the control cells flattened readily on plastic and formed a branching monolayer, the Ins-rPLII cells remained more rounded, sent out fewer projections, and formed more numerous (p<0.01) and larger (p<0.01) beta-cell clusters. Larger clusters assumed a spherical form with well-delineated smooth borders and detached more readily from the culture plates. Maturational progression of the Ins-rPLII cells was associated with a 40% increase in preproinsulin mRNA (p<0.05) and a 2-3-fold increase in glut-2 mRNA (p<0.01). Induction of glut-2 mRNA was accompanied by a 1.4-2.4-fold increase (p< 0.01) in the uptake of radiolabeled 2-deoxyglucose. Similar effects were observed in INS-1 cells exposed for 48 h to exogenous prolactin. These findings suggest novel roles for the lactogenic hormones in the maturation and growth of pancreatic islets. Lactogen induction of beta-cell aggregation coupled with localized beta-cell growth may contribute to the expansion of islet mass that occurs in pregnancy and during the perinatal period. The induction of insulin and glut-2 mRNA provides a mechanism by which the lactogens may increase fetal and maternal insulin production and enhance the sensitivity of the pancreas to glucose.

Duke Scholars

Published In

Pediatr Res

DOI

ISSN

0031-3998

Publication Date

January 2000

Volume

47

Issue

1

Start / End Page

136 / 142

Location

United States

Related Subject Headings

  • Tumor Cells, Cultured
  • Rats
  • RNA, Messenger
  • Placental Lactogen
  • Pediatrics
  • Monosaccharide Transport Proteins
  • Lymphoma
  • Islets of Langerhans
  • Insulin
  • Immunohistochemistry
 

Citation

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Fleenor, D., Petryk, A., Driscoll, P., & Freemark, M. (2000). Constitutive expression of placental lactogen in pancreatic beta cells: effects on cell morphology, growth, and gene expression. Pediatr Res, 47(1), 136–142. https://doi.org/10.1203/00006450-200001000-00023
Fleenor, D., A. Petryk, P. Driscoll, and M. Freemark. “Constitutive expression of placental lactogen in pancreatic beta cells: effects on cell morphology, growth, and gene expression.Pediatr Res 47, no. 1 (January 2000): 136–42. https://doi.org/10.1203/00006450-200001000-00023.
Fleenor, D., et al. “Constitutive expression of placental lactogen in pancreatic beta cells: effects on cell morphology, growth, and gene expression.Pediatr Res, vol. 47, no. 1, Jan. 2000, pp. 136–42. Pubmed, doi:10.1203/00006450-200001000-00023.

Published In

Pediatr Res

DOI

ISSN

0031-3998

Publication Date

January 2000

Volume

47

Issue

1

Start / End Page

136 / 142

Location

United States

Related Subject Headings

  • Tumor Cells, Cultured
  • Rats
  • RNA, Messenger
  • Placental Lactogen
  • Pediatrics
  • Monosaccharide Transport Proteins
  • Lymphoma
  • Islets of Langerhans
  • Insulin
  • Immunohistochemistry