Vasoactive intestinal peptide increases prolactin messenger ribonucleic acid content in GH3 cells
Related Experiment Videos
Abstract:
The influence of vasoactive intestinal peptide (VIP), TRH, and dexamethasone (Dex) on PRL mRNA was investigated in PRL-producing GH3 cells using cytoplasmic dot hybridization and RNA blot analysis. Total cytoplasmic RNA was transferred to nitrocellulose filter paper and quantitated by hybridization to PRL recombinant DNA probes labeled with 32P. Incubation of GH3 cells with VIP for 25 h increased the content of cytoplasmic PRL mRNA. This increase was dose dependent, being significant at 2 X 10(-8) M and reaching a maximum at 2 X 10(-7) M. VIP at 2 X 10(-9) M had no effect on cytoplasmic PRL mRNA content. TRH (2 X 10(-7) M) also increased whereas Dex (2 X 10(-7) M) decreased the content of PRL mRNA. The inhibitory effect of Dex (2 X 10(-7) M) on cytoplasmic PRL mRNA was reversed by VIP (2 X 10(-7) M). Changes in medium PRL levels after these various hormone treatments paralleled those changes observed in PRL mRNA content. Examination of total poly(A)+ RNA demonstrated that incubation with VIP (2 X 10(-7) M) for 6 h increased the content of the mature PRL mRNA and its processing intermediates. Dex (2 X 10(-7) M) decreased the content of all species of PRL mRNA. These data suggest that VIP-stimulated PRL release is the result of an increase in the content of PRL mRNA and its precursors.
Insights
Vasoactive intestinal peptide (VIP) and TRH increase prolactin (PRL) mRNA levels in GH3 cells, while dexamethasone (Dex) decreases them. VIP can reverse Dex
Area of Science:
- Endocrinology
- Molecular Biology
- Cell Biology
Background:
- Prolactin (PRL) is a key hormone regulating various physiological processes.
- The regulation of PRL production involves complex signaling pathways.
- GH3 cells are a commonly used model for studying pituitary hormone secretion.
Purpose of the Study:
- To investigate the effects of vasoactive intestinal peptide (VIP), thyrotropin-releasing hormone (TRH), and dexamethasone (Dex) on PRL mRNA levels.
- To determine the impact of these hormones on PRL release from GH3 cells.
- To elucidate the molecular mechanisms underlying VIP- and Dex-mediated regulation of PRL synthesis.
Main Methods:
- GH3 cells were treated with varying concentrations of VIP, TRH, and Dex.
- Cytoplasmic dot hybridization and RNA blot analysis were employed to quantify PRL mRNA.
- PRL levels in the cell medium were measured to correlate with mRNA changes.
- Analysis of poly(A)+ RNA examined mature PRL mRNA and its processing intermediates.
Main Results:
- VIP significantly increased cytoplasmic PRL mRNA content in a dose-dependent manner.
- TRH also elevated PRL mRNA levels, whereas Dex decreased them.
- Dex-induced inhibition of PRL mRNA was reversed by VIP treatment.
- Changes in PRL mRNA levels directly correlated with PRL secretion into the medium.
- VIP increased both mature PRL mRNA and its precursors, while Dex decreased all PRL mRNA species.
Conclusions:
- VIP stimulates PRL release by increasing the content of PRL mRNA and its precursors.
- TRH enhances PRL mRNA levels, contributing to PRL secretion.
- Dexamethasone inhibits PRL production through a reduction in PRL mRNA.
- VIP can counteract the suppressive effects of Dex on PRL synthesis.
- These findings highlight the intricate hormonal regulation of PRL production at the mRNA level.