Endocrine Abstracts

Oestrogen is an important regulator of the pituitary hormone prolactin (PRL) in vivo, although the regulation mechanism is poorly understood. Liganded oestrogen receptor (ER) synergises with the pituitary specific factor Pit-1 on the rat PRL promoter to facilitate chromatin looping and increased transcription; however, no such mechanism has been reported for the human PRL promoter, in which the ERE sequence is altered.In pituitary GH3 cells stably transf...

Prolactinomas are the commonest type of functioning pituitary adenoma in man. High circulating oestrogen levels are associated with lactotroph proliferation and increased PRL secretion essential for lactation. In vitro, oestradiol induces proliferation of the rat pituitary somatolactotroph GH3 cell line, and chronic oestrogen treatment of Fischer-344 rats in vivo results in lactotroph hyperplasia and adenoma formation, though the mechanisms responsible remain elu...

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 ...

The neuroendocrine and immune systems are closely linked, and cytokines such as IL-1, IL-6 and tumour necrosis factor-alpha (TNF-alpha), secreted by immune cells or neighbouring pituicytes, may have important local effects on pituitary function to modulate endocrine mechanisms of regulation.We have analysed the transcriptional regulation of the human prolactin (hPRL) gene promoter by TNF-alpha. Using stably transfected GH3 cells expressing luciferase und...