[Immunohistochemical study of the chick oviduct with antibodies to the progesterone receptor].

Three antibody preparations against the progesterone receptor (PR) were used: a Rabbit and a Goat immunoglobulin fraction, and a monoclonal antibody. Oviducts were stimulated by administration of estradiol to the animals in order to obtain different cell types, particularly the epithelial and glandular cells which synthesize the egg white proteins under progesterone control. Using an immunoperoxidase technique, all three antibodies reacted with antigens in more than half the cells of the luminal epithelium. The specificity was shown by the extinction of the reaction by PR added to the antibodies, and by negative controls in absence of antibodies to PR. The results strongly suggest the presence of PR in epithelial cells. Remarkably, glandular cells did not react with antibodies to PR. This observation and problems raised by cross-reactivity of antibodies with glucocorticosteroid receptor are discussed.