Functional and structural differences between cultured outer and inner layer cells of bovine adrenal cortex

Influence of extracellular matrix on the proliferation and differentiation of adrenocortical cells in culture

Extracellular matrix is indispensable for cell differentiation in vivo. The aim of this study is to examine effects of extracellular matrix on adrenocortical cells embedded in collagen gel in terms of cellular proliferation and differentiation. Dissociated human or bovine adrenocortical cells were embedded in collagen gel; the gel was then immediately thin-coated on the bottom of culture dishes. The cortical cells were thus trapped in collagen and cultured in monolayer, a suitable means for observation of culture cells. To the authors' best knowledge, this "collagen gel-embedded" monolayer culture is described here for the first time. Cortical cells were spherical in shape and had the activities of proliferation and steroid production in collagen gel matrix of this culture method. Aldosterone production in particular tended to be maintained much longer than in conventional monolayer culture. This method seems to provide a physiological environment in which to study the differentiation of cortical cells.

Morphological and functional comparison of subcapsular small cells, subcapsular large cells and inner layer cells of bovine adrenal cortex

Subcapsular small cortical cells (SC cells) and subcapsular large cortical cells (LC cells) of bovine adrenal cortex were cultured separately after purification by unit gravity sedimentation, and then compared with inner-half layer cells (IL cells) prepared by the same method. Both SC and LC cells were polygonal in shape and their mitochondria were elongated with lamellar cristae. SC cells became as large as LC cells on day 6 of culture with increased cytoplasmic lipid droplets, whereas IL cells showed no change in size. IL cells were spindle-shaped and had mitochondria with tubulovesicular cristae. Both SC and LC cells produced 11 beta-deoxycorticosterone, corticosterone, aldosterone and small amounts of 17 alpha-hydroxyprogesterone (17 alpha-OH-Prog) and cortisol (F). IL cells produced much more 17 alpha-OH-Prog and F than SC or LC cells. When stimulated with ACTH, cortical cells in each group showed cellular retraction and their mitochondria became spherical. The amounts of 17 alpha-OH-Prog and F increased in all groups, especially in IL cells. These results show that LC cells have similar characteristics to SC cells in both morphology and function, and that they differ from IL cells, which correspond to classical fasciculata-reticularis cells.