The production of CINC/gro, a member of the interleukin-8 family, in rat anterior pituitary gland.

We investigated the possibility of detection of CINC/gro, which is a IL-8-like neutrophil chemoattractant, immunoreactivity in rat normal anterior pituitary gland by immunohistochemistry, western blot analysis and an ELISA. We first ascertained the possibility of detection of CINC/gro immunoreactivity in the anterior pituitary gland by immunocytochemistry. In the anterior lobe of the pituitary gland, a few CINC/gro-like immunoreactive cells were observed (1-3% of all cells in the anterior pituitary). The positive cells were middle or large in size and looked angular in shape. Intense immunoreactivity was observed in the cytoplasm but not in the nucleus. Analysis by immunoblotting with anti-CINC/gro antiserum gave a characteristic single CINC/gro band with a molecular weight of 6.3 kDa. CINC/gro immunoreactivity was also detected in 3-h conditioned medium of normal anterior pituitary cells by an ELISA, and that immunoreactivity increased significantly in a time-dependent manner during 24-h incubation. This immunoreactivity could be induced by TNF-alpha in a dose-dependent manner. These findings indicate that CINC/gro is produced in pituitary gland and also suggests the possibility that CINC/gro may play some role asa modulator of anterior pituitary function, especially in the cross-talk mechanism between the immune and neuroendocrine systems.