2-METHOXYETHANOL INHIBITS GAP JUNCTIONAL COMMUNICATION IN RAT MYOMETRIAL MYOCYTES

The glycol ethers 2-methoxyethanol (2-ME) and 2-ethoxyethanol (2-EE) p rolong gestation in rodents. Because gap junctions in the myometrium l ikely facilitate parturition, the present study examined inhibition of gap junctional communication by 2-ME and 2-EE in myometrial smooth-mu scle cell cultures. To measure gap junctional communication, the fluor escent dye Lucifer yellow was injected into cultured cells and the tra nsfer of the dye to adjacent cells was scored with epifluorescence mic roscopy. The data are presented as the percentage of cells adjacent to the microinjected cell that exhibited dye following microinjection. A 30 min treatment with 32 or 63 mmol/L 2-ME decreased dye transfer to 71% and 63%, respectively (p less than or equal to 0.05; control 90%). Similarly, 2-EE inhibited dye transfer, although myometrial cells wer e less sensitive to 2-EE compared to 2-ME. Dye transfer returned to co ntrol levels after 2 h in the continued presence of 2-ME. The primary metabolite of 2-ME, methoxyacetic acid (MAA), had no effect on dye tra nsfer at concentrations equimolar to 2-ME. Because 2-ME and 2-EE inhib ited gap junctional communication only at high concentrations and beca use the inhibition reversed in the continued presence of the compounds , it is suggested that glycol ethers delay parturition by a mechanism independent of a direct action on myometrial gap junctions.