In situ hybridization of BMP-7 mRNA in ovaries of adult cycling rats. Brightfield (A, C, D, F, G) and Darkfield (B, E). A, B: Sections of DI 1100 h ovaries (4X); positive Graafian follicle (GF); positive new CL-I; negative old CL-I and SIC; C: Positive sex cords at E 0200 h (40X); D, E: Dominant follicle at P 2000 h (4X) showing positive theca interna. F: Higher magnification (40X) of D showing positive fibroblast-like cells beneath the basal lamina and adjacent positive TIC (). G: CL-I at DI 1100 h showing positive theca lutein cells (40X).