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

Robert L. Sorenson, T. Clark Brelje, Orion D. Hegre, Sue Marshall, Pat Anaya, Judson D. Sheridan

Research output: Contribution to journalArticlepeer-review

67 Scopus citations

Abstract

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 μg/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 ≪ 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 μU/ml · 100 μg islet tissue as compared to control islets 94 ± 20 μU/ml-100 μg islet tissue (n = 7, p ≪ 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 ≪ 0.001). Mean islet volume was unchanged after 4 days of oPRL treatment but was 34% greater after 8 days (n = 6, p ≪ 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 ≪ 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.

Original languageEnglish (US)
Pages (from-to)1447-1453
Number of pages7
JournalEndocrinology
Volume121
Issue number4
DOIs
StatePublished - Oct 1 1987

Fingerprint Dive into the research topics of 'Prolactin (in vitro) decreases the glucose stimulation threshold, enhances insulin secretion, and increases dye coupling among islet b cells'. Together they form a unique fingerprint.

Cite this