Up to an age of about 7 weeks the adrenal glands of male and female mice grow rapidly in order to grant for the appropriate supply of adrenal hormones to the increasing blood volume and body size. In mice, a functional zona reticularis is absent, instead, the so-called X-Zone can be found during certain postnatal developmental stages in mice. 2003), the adrenal cortex can roughly be divided into three different zones: the outer zona glomerulosa, followed by the zona fasciculata and the zona reticularis which directly surrounds the medulla. Although the classical view of a concentric arrangement and a strict separation of the different adrenal zones is oversimplified ( Whitworth et al. In mice, zonation of the cortex occurs soon after birth.

Both cell populations are encapsulated before birth and establish the cortical and the medullary compartments. In mammals, the adrenal cortex and medulla are formed during embryogenesis by two distinct cell populations deriving from mesodermal and neuroectodermal origins ( Hammer et al. On the basis of these multiple exogenous or endogenous factors which impact on the adrenal gland through ERK1/2 activity, we speculate on a mechanism by which ERK1/2 act as a central integrative growth regulatory elements in the adrenal gland. We then discuss intracellular mechanisms of adrenal growth control and focus on extracellular signal regulated kinases 1/2 (ERK1/2), which have been demonstrated to be controlled by not only ACTH or angiotensin II, but also by a large number of additional effectors. In the present review, we summarize the current view of endocrine growth control in the adrenal gland. Among those are diverse hormones, psychosocial parameters, physiological stress, secondary plant products, or even environmental pollutants. However, control of the adrenal gland comprises a plethora of additional endogenous or exogenous factors. This axis involves hypothalamic CRH and pituitary ACTH which determine processes of adrenocortical growth and function. According to the present understanding, the adrenal cortex is tightly controlled by the hypothalamic–pituitary–adrenal axis. The adrenal gland influences a multitude of processes during stress response, but also potently affects the immune system, glucose metabolism, electrolyte or water homeostasis, and cardiovascular functions.

Cortical hormone function