Proliferative activity in the corpus luteum of pregnant rats of the control, hypothyroid and hyperthyroid groups at 10, 14 and 19 days of gestation. A) Immunohistochemical images of CDC-47 expression. Marked reduction of the number of cells with CDC-47 expression in the corpus luteum of the hypothyroid group compared to the control group at 10 and 14 days of gestation (Streptavidin-biotin-peroxidase, Harris hematoxylin, scale bar = 12 μm). B-D) Percentage of cells with CDC-47 (means ± SD) expression in histological sections of the corpus luteum. (*P < 0.05; **P < 0.01; ***P < 0.001).