Localization of macrophages in the chicken oviduct: effects of age and gonadal steroids.

The aim of this study was to localize macrophages in the hen oviduct and determine the effects of age and gonadal steroids on their population. Cryostat sections of oviducal tissues from immature hens (60 d of age), virgin young (175 d of age), and old (620 d of age) laying hens, and immature hens (84 d of age) treated with gonadal steroids were immunostained for macrophages. The population of macrophages was analyzed by an image analysis system under a light microscope. Macrophages were observed in the stroma and mucosal epithelium of all oviducal segments of immature and laying hens. The population of macrophages in the oviducal stroma increased with age. Young laying hens had a significantly higher population of macrophages than immature hens in the vagina. Old laying hens had a significantly higher population than immature hens in the infundibulum, magnum, and vagina, and than young laying hens in the magnum. In the immature hens treated with gonadal steroids, the macrophage population increased only in the stroma of shell gland of the progesterone-treated birds. These results indicate that macrophage population in the oviducal stroma increases in association with sexual maturation and aging. Their population in the stroma may be partially affected by progesterone.