Abstract
A variety of stimuli deriving from the brain and peripheral endocrine organs modify the secretion and synthesis of prolactin (PRL) in lactotrophs. Although there are numerous studies of in vivo and in vitro regulation of PRL secretion and mRNA expression by these stimuli, the regulation of prolactin transcription has been elucidated only in lactotroph cell lines. This is due to low efficiencies for transfection of transcriptional reporter genes in primary cultures and in vivo. Here we report the establishment of lactotroph-specific luciferase expression mediated by infection of recombinant adenovirus vector to rat anterior pituitary primary cultures. The luciferase gene located downstream of the rat PRL promoter gene (3.3 kb) was inserted as a reporter gene into Adeno-X vector. Double fluorescence immunocytochemistry revealed that the luciferase protein was expressed specifically in lactotrophs and not in other pituitary cell types. The luciferase assay was sensitive enough to detect the activity even in pituitary primary cultures containing 105 cells. The luciferase activity was elevated after the treatment with several stimuli including insulin-like growth factor I. These results suggest that adenovirus-mediated luciferase gene expression under the control of PRL promoter gene is a useful method for determination of PRL promoter activity in primary lactotroph cultures. [Jpn J Physiol 54 Suppl:S221 (2004)]
