Some Morphological and Functional Characteristics of Cells of the Porcine Theca Interna in Tissue Culture1

Abstract

Theca interna cells were collected from large porcine follicles in the follicular phase of the cycle. The theca interna layer was manually separated from the theca externa, washed thoroughly, occasionally treated with hyaluronidase solution and trypsinized. The resulting cell suspension consisted of approximately 70% theca interna cells, 8% granulosa cells and 23% nonsteroidogenic cells. In one experiment, cells collected from the granulosa layer and the theca interna of the same follicles were compared. Specific cell types were identified by: 1) staining with Oil Red O (ORO) to visualize lipid droplets in the cytoplasm; 2) measuring activity of the Δ5, 3β-hydroxysteroid dehydrogenase (Δ5, 3β-OH SH) enzyme and 3) quantitating estrogen production by the cultured cells. Nonsteroidogenic cells do not stain by any of the techniques applied. Theca interna cells can be distinguished from granulosa cells in suspension prior to culture by the following criteria: 1) more intense staining with ORO; 2) stronger Δ5, 3β-OH SH activity and 3) larger cell size. Theca interna cells in culture can be differentiated from granulosa cells by the following parameters: 1) more elongated shape; 2) slower and more chaotic growth; 3) weaker enzyme activity and 4) increased estrogen production.