Figure 1.
Representative photomicrographs showing smears from rats in metestrus/diestrus, proestrus and estrus. A: Metestrus is characterized by the appearance of small leukocytes, mixed with round or irregular shaped nucleated or squamous epithelial cells in a vaginal smear. B: Diestrus smear has fewer leukocytes mixed with cornified epithelial cells. C: The smear from a proestrus rat is characterized by a predominance of round nucleated cells of uniform size, with a complete absence of leucocytes. Cells are distributed individually or in clusters. D: Estrus, nonnucleated cornified epithelial cells are predominant.