Prepubertal Dogs Research Articles

24 prepubertal 6-8 week old Beagle dogs were injected intramuscularly every other day either with 150 mcg/kg estradiol-beta valerate (14), or progesterone respositol (5), or used as controls (5) to determine what effect estrogen and progesterone had on cytodifferentiation. Light and electron micrographs of the oviductal epithelium of the ampullae of the controls and hormone-treated dogs were studied. The epithelial cells in the controls were uniformly low cuboidal with a high nucleocytoplasmic ratio. After 36 hours of estradiol treatment there was nuclear and nucleolar hypertrophy; an increase in the numbers of cytoplasmic polyribosomes and numerous mitotic figues were apparent. Ciliogenesis began and 2 cell types were distinguishable after 3 days of estradiol treatment. Basal bodies in various stages of formation were randomly distributed throughout the apex of many cells. In others, more mature basal bodies were aligned at the apical border or cilia were evident. 6 days of estradiol resulted in complete ciliation of approximately 60% of all epithelial cells. The remaining cells possessed abundant cisternae of rough endoplasmic reticulum (RER) and appeared to be differentiating into mucus-secreting cells. After 10 days, these cells possessed a large Golgi apparatus, large dilated cisternae of RER, and abundant periodic-acid-Schiff positive granules at their apex. Progesterone treatment alone produced no hypertrophy of the oviductal epithelium. In fact, cytomorphometric measurements indicate that progesterone had an opposite effect, causing atrophy (p less than.05) and increasing the nucleocytoplasmic ratio. It is concluded that estrogen alone was capable of producing complete cytodifferentiation in the oviduct of the prepubertal dog.