The Differentiation and Organization of Tumors in vitro

Distribution of 3β-hydroxysteroid dehydrogenase during development of the rat adrenal cortex and capsule

“…The overlap of formazan deposition, dense reticular fibers, and intense PAS staining with the layer of elongated cells at the adrenocortical periphery was interpreted as evidence that 3P-HSD activity was present in the region of the developing adrenocortical connective-tissue capsule. After birth, enzyme activity in the region of the capsule persisted for about 1 week, and then diminished as development progressed ( Figs. 12, 13).…”

“…On the basis of these observations, the hypothesis was proposed that capsular fibroblasts have the potential to give rise to steroidogenic parenchymal adrenocortical cells. More recently, this hypothesis has fallen into disrepute for several reasons: (1) in adult glands, the capsule is histochemically devoid of steroidogenic enzyme activity; (2) in cultures of adrenocortical parenchymal cells, contaminating fibroblasts show no evidence of steroidogenic potential or responsiveness to ACTH ; (3) the experiments that have directly demonstrated that capsular cells migrate into the cortex [23] have not been reproducible [19]; (4) in regeneration and in response to ACTH stimulation. mitotic activity and thymidine incorporation are observed in the zona glomerulosa rather than in the capsule [6,7,241.…”

V-K-ras transformation induces reversion to an earlier developmental form in adult rat adrenal cells

“…2). In vivo, TRA 27/I and TRA 5/IV formed carcinomas while TRA 7/X-1 and TRA 21/X produced fibrosarcomas [5] (Fig. 3).…”

“…In the present study, KiMSV-mediated transformation was compared in short-term cultures and in spontaneously immortalized lines derived from the same cells, to distinguish the role of immortalization from other aspects of transformation by KiMSV. Since the regulation of differentiation is altered in immortal lines [5,111, such comparisons are necessary to evaluate the validity of the many extrapolations that are made from observations on immortal lines to cells in short-term culture. In addition, short-term cultures were used to determine whether v-ras-mediated transformation enhances only parenchymal characteristics, or whether it also affects stromal differentiation markers.…”