IMMORTALIZED HYPOTHALAMIC LUTEINIZING-HORMONE-RELEASING HORMONE NEURONS EXPRESS A CONNEXIN 26-LIKE PROTEIN AND DISPLAY FUNCTIONAL GAP JUNCTION COUPLING ASSAYED BY FLUORESCENCE RECOVERY AFTER PHOTOBLEACHING

Expression of gap junction proteins was studied in the LHRH neuronal c ell line, GT1-7, as a first step in defining the signalling mechanisms responsible for the pulsatile secretion of LHRH. GT 1-7 cells were fo und to express a connexin 26-like protein that comigrated with mouse l iver connexin 26 and that reacted with connexin 26-specific antibodies on Western blots. Immunofluorescent staining revealed punctate staini ng in a fraction of the cells, often present at points of apparent con tact with neighboring cell bodies or processes. Fluorescence recovery after photobleaching analysis of 5,6-carboxyfluorescein loaded GT1-7 c ells showed dye coupling among 20-30% of cells that made contact with other cells, suggesting the presence of functional gap junctions in th is cell line.