['Peri-ovulatory migration of leukocytes towards the follicle plays an important role during corpus luteum formation. In this study, we examined the secretion of the neutrophil chemoattractant interleukin (IL)-8 by ovarian GL cells and the role of monocytes in IL-8 secretion.', 'Granulosa-lutein cells were isolated from the pre-ovulatory follicle. After depletion of contaminating leukocytes, GL cells were co-cultured with the myelo-monocytic cell line THP-1. Intracellular IL-8 accumulation, IL-8 secretion, and chemotactic activity of cell culture media were examined.', 'Intracellular IL-8 was predominantly localized in the endoplasmatic reticulum-Golgi both in GL cells and in THP-1 cells. In co-cultured cells, intracellular IL-8-specific immunofluorescence and IL-8 secretion were increased compared with either GL cells or THP-1 cells that were cultured alone. Conditioned cell culture media from GL cells and THP-1 cells induced directed cell migration by neutrophils.'] Does cellular interaction regulate interleukin-8 secretion by granulosa-lutein cells and monocytes/macrophages?