I. Observations by Light and Scanning Electron Microscopy

Experiments were conducted to determine cellular alterations in the magnum and shell gland of undeveloped avian oviducts in response to treatment with estradiol-1713 or Kepone. Groups of immature Japanese quail females, kept in a reduced photoperiod, received injections of 40 g estradiol-171/day for periods of 6-26 days while other groups were fed diets with 10, 40, 80 or 160 ppm of the estrogenic insecticide Kepone for the same duration. Both estradiol and Kepone produced an increase in oviduct weight. Estradiol accelerated cellular proliferation, cytodifferen-tiation and tubular gland formation and induced secretory activity in cells of the magnum and shell gland. In response to estradiol, the luminal surface exhibited increased numbers of microvilli and tubular gland depressions; the ciliation eventually became continuous and profuse. In both regions of the oviduct the cilia were well formed, tall and uniformly arranged and their tips were associated with blebs suggestive of secretory product. Ingestion of Kepone produced dose.dependent changes in oviduct structure. After Kepone ingestion, changes similar to those produced by estradiol were seen in the magnum and shell gland. However, the secretory granules were smaller and less numer-ous. Low levels of Kepone induced pronounced swelling of cells with extreme apical protrusions covered by microvilli and long ciiary tufts. Higher Kepone doses induced profuse, continuous ciliation; however, in contrast to the condition in the estradiol treated group, the cilia exhibited irregular arrangement, disorientation and twisting. In addition, Kepone apparently reduced but did not abolish the secretory blebs associated with the oviduct cilia