Histological evaluation of the dopaminergic regulation of proopiomelanocortin gene expression in the intermediate lobe of the rat pituitary, involving in situ hybridization and [3H]thymidine uptake measurement

Endocrinology
B M ChronwallT L O'Donohue

Abstract

The melanotroph, a polyhedral secretory cell with an ovoid smooth nucleus, is the primary cell type of the intermediate lobe (IL) of the rat pituitary. The melanotrophs are not uniform, but differ in the tinctorial properties of their cytoplasm; some cells appear distinctly darker, others lighter, and cells staining in intermediate shades are also found. In addition, in situ hybridization using proopiomelanocortin (POMC) probes shows an uneven distribution of POMC mRNA among melanotrophs, indicating that different cells maintain different levels of biosynthetic activity. Dopaminergic drugs known to alter the secretion of POMC-related peptides from the IL produced parallel changes in histological staining properties and the amount of POMC mRNA per cell, as determined by in situ hybridization. Acute bromocriptine treatment (6 h) produced a dramatic reduction in grain counts over melanotroph cytoplasm (to 10% of the control levels). A similar reduction persisted after chronic treatment. Six hours after a single haloperidol injection, the grain counts were 180% of control levels. After chronic haloperidol treatment, they were further elevated to 300% of control levels. Chronic bromocriptine and haloperidol treatment also changed th...Continue Reading

Citations

May 1, 1993·Microscopy Research and Technique·J H EberwineA R Hoffman
May 7, 1990·Molecular and Cellular Endocrinology·C HindelangM E Stoeckel
Apr 1, 1992·International Journal of Developmental Neuroscience : the Official Journal of the International Society for Developmental Neuroscience·K A Gary, B M Chronwall
Apr 1, 1996·International Journal of Developmental Neuroscience : the Official Journal of the International Society for Developmental Neuroscience·B M ChronwallK A Gary
Jun 6, 1998·Biochimica Et Biophysica Acta·A EisenJ Lucchesi
Jun 1, 1997·International Journal of Developmental Neuroscience : the Official Journal of the International Society for Developmental Neuroscience·S A Sands, B M Chronwall
Jun 18, 1998·Annals of the New York Academy of Sciences·Francisco Gracia-NavarroMaria M Malagon
Feb 17, 2000·Annals of the New York Academy of Sciences·B M ChronwallS A Sands
Jun 16, 2011·Biomedical Research·Toshihiko IwanagaHiromi Takahashi-Iwanaga
May 31, 1993·Annals of the New York Academy of Sciences·B M ChronwallK A Gary
Aug 1, 1996·International Journal of Developmental Neuroscience : the Official Journal of the International Society for Developmental Neuroscience·D M BeattyB M Chronwall
Dec 12, 2001·Endocrine Reviews·N Ben-Jonathan, R Hnasko
Jan 14, 1999·Endocrinology·J L Gonzalez de AguilarFrancisco Gracia-Navarro
Jan 20, 2006·Journal of Endocrinological Investigation·Rafael Vazquez-MartinezMaria M Malagon
Jul 24, 2003·American Journal of Physiology. Endocrinology and Metabolism·Rafael Vazquez-MartinezMaria M Malagon

Related Concepts

Autoradiography
Parlodel
Cell Division Phases
Cistron
Haldol
Genomic Hybridization
Pituitary Stalk
Opiocortin
August Rats
Thymidine

Related Feeds

Antipsychotic Drugs

Antipsychotic drugs are a class of medication primarily used to manage psychosis (including delusions, hallucinations, paranoia or disordered thought), principally in schizophrenia and bipolar disorder. Discover the latest research on antipsychotic drugs here