Endocrine Abstracts

Prolactin (PRL) is a hormone mainly produced by the lactotroph cells of the anterior pituitary gland. Besides its pivotal role in reproduction, PRL has also been found to have immuno-modulatory properties. The pituitary is the main source of circulating PRL, however it is also expressed in humans at extra-pituitary sites1. In extra-pituitary tissues, PRL mRNA contains an extra exon (exon 1a), and expression is regulated by an alternative promoter upstream of the pit...

Prolactin (PRL) is a peptide hormone produced by the anterior pituitary gland and it is commonly known for its lactogenic and mammotrophic effects. In humans and primates, prolactin is also expressed in extra-pituitary sites where it is associated with numerous biological functions, but its spectrum of expression varies in different species.Hyperprolactinemia-induced osteoporosis is believed to be mediated by hypogonadism, but the expression of the prola...

Circulating levels of prolactin are subject to acute and long-term regulation by many factors including oestrogen and dopamine. We have studied the regulation of prolactin promoter activity in living pituitary cells using transgenic Fischer rats in which reporter gene expression is regulated by the human prolactin gene locus (hPRL-d2EGFP). We have previously identified pulsatile prolactin transcription patterns in living lactotroph cells in fetal tissue, that became stabilised...

Oestrogens are capable of inducing rat prolactin gene transcription through liganded Oestrogen Receptor (ER) binding a degenerate oestrogen response element (ERE) sequence on the promoter 1440 bp upstream of the transcription start site. ER binding is thought to interact with DNA bound Pit-1 leading to chromatin looping bringing enhancer elements into proximity with the transcription start site. This ERE sequence, TGTCActaTGTCA, differs from the consensus GGTCAnnnTGACC by two ...

Circulating levels of prolactin are subject to acute and long-term regulation by many factors including oestrogen and dopamine. We have studied the regulation of prolactin promoter activity in living pituitary cells using transgenic Fischer rats in which reporter gene expression is regulated by the human prolactin gene locus (hPRL-d2EGFP). We have previously identified pulsatile prolactin transcription patterns in living lactotroph cells in fetal tissue, that became stabilised...

Alternative promoters control many genes including prolactin (PRL), which in man is expressed at extra-pituitary sites controlled by an alternative promoter located 5.8 Kbp upstream of the pituitary transcription start site. Previous studies using short promoter fragments may be misleading, as the human hPRL genomic locus has many conserved far-upstream regions. To study the function of the alternative promoter, we engineered a bacterial artificial chromosome (BAC) expressing ...

Gene expression in living cells is dynamic and unstable, and fluctuations in transcription may be subject to stochastic regulation of processes including transcription factor and polymerase recruitment, and chromatin remodelling. One gene that has been shown to display dynamically variable transcription and marked heterogeneity between cells is prolactin (PRL). Time-lapse imaging of PRL-reporter gene expression in single rat pituitary GH3 cells revealed distinct long-term tran...

Pituitary development, in particular the differentiation of anterior pituitary endocrine cells, remains to be fully understood, and may have implications for adult pituitary plasticity and hyperplasia. We have used prolactin-reporter transgenic rats to characterise prolactin transcription during the appearance of newly formed lactotroph cells during fetal development.Transgenic rats with the firefly luciferase reporter gene inserted into exon 1b of a 160...