Opossum adrenal medulla: I. Postnatal development and normal anatomy

Abstract

The anatomy and histology of the adrenal gland in the adult opossum were found to be typical for mammals. The development of the adrenal medulla was also found to follow the typical mammalian pattern. Primitive sympathetic cells were found in both intra- and extra-adrenal locations in the newborn at a time when chromaffin precursor cells were migrating to the adrenal anlage. Pheochromoblasts first appeared within the forming medulla where at a later stage chromaffin cells could be observed forming columns of cells between adjacent sinusoids. Unlike in other mammals, much of this development takes place postnatally when the neonate is in the mother's marsupium. The value of the developing opossum adrenal medulla as an experimental model is stressed, since a significant amount of development takes place in an environment that is accessible to experimental manipulation.

A Morphological and Histological Examination of the Pan‐tropical Spotted Dolphin (Stenella attenuata) and the Spinner Dolphin (Stenella longirostris) Adrenal Gland

“…The general histology of both Stenella adrenal glands was similar to that of other mammals (Bourne, 1949; Carmichael et al., 1987; Abdalla and Ali, 1989), including what has been described in a limited number of cetaceans (Jacobsen, 1941; Harrison, 1969; Simpson and Gardner, 1972; Britt and Howard, 1983; Zhongjie, 1988; Kirby, 1990; St. Aubin, 2002; Clark et al., 2005), with an outer zoned cortex and a central medulla.…”

“…Medullary protrusions have been reported in a limited number of other cetaceans, including Kogia breviceps (Kirby, 1990) and Mesoplodon europaeus (Carballeira et al., 1987), but these earlier studies did not quantify the number of protrusions present. Currently, the functional significance of medullary protrusions in cetacean is unknown; however, they could be related to the adrenal hilus as reported for the opossum (Carmichael et al., 1987). Histologically, cells of the medullary protrusions in both Stenella species resembled the noradrenaline‐producing cells identified in the central medulla in T. truncatus (Clark et al., 2005, 2006).…”

Immunohistochemical Study of the Developing Endocrine Pancreas of the Opossum (<i>Didelphis virginiana</i>)

“…1983: Johnson. 1987], The adrenal, thyroid and pituitary of Didelphis are very immature in appearance during the first postnatal weeks and it is not until much later that they begin to show mature features [Carmichael et al. 1987: Krauseand Cutts.…”

PC12 cells differentiate into chromaffin cell-like phenotype in coculture with adrenal medullary endothelial cells.

“…For example, humoral signals derived from pulmonary endothelial cells might influence fetal lung development and differentiation (26). During early stages ofdevelopment prior to the establishment of a basement membrane, cell-cell contacts between the migrating neural crest-derived cells and the vascular endothelial cells might contribute to the final fate and differentiation of both cells (13).…”

“…We recently hypothesized that vascular endothelial cells may also be involved in regulating the pathway of neural crest cell differentiation (12). Indeed, Carmichael et al (13) suggested that capillary endothelial cells might regulate the neonatal development of chromaffin cells in the opossum adrenal medulla.…”