By stimulating adrenal gland and corticosteroid synthesis, the adrenocorticotropic hormone (ACTH) plays a central role in response to stress. In this Research Topic, a particular attention has been given to the recent developments on adrenocortical zonation; the growth-promoting activities of ACTH; the various steps involved in acute and chronic regulation of steroid secretion by ACTH, including the effect of ACTH on circadian rhythms of glucocorticoid secretion. The Research Topic also reviews progress and challenges surrounding the properties of ACTH binding to the MC2 receptor (MC2R), including the importance of melanocortin-2 receptor accessory protein (MRAP) in MC2R expression and function, the various intracellular signaling cascades, which involve not only protein kinase A, the key mediator of ACTH action, but also phosphatases, phosphodiesterases, ion channels and the cytoskeleton. The importance of the proteins involved in the cell detoxification is also considered, in particular the effect that ACTH has on protection against reactive oxygen species generated during steroidogenesis. The impact of the cellular microenvironment, including local production of ACTH is discussed, both as an important factor in the maintenance of homeostasis, but also in pathological situations, such as severe inflammation. Finally, the Research Topic reviews the role that the pituitary-adrenal axis may have in the development of metabolic disorders. In addition to mutations or alterations of expression of genes encoding components of the steroidogenesis and signaling pathways, chronic stress and sleep disturbance are both associated with hyperactivity of the adrenal gland. A resulting effect is increased glucocorticoid secretion inducing food intake and weight gain, which, in turn, leads to insulin and leptin resistance. These aspects are described in detail in this Research Topic by key investigators in the field. Many of the aspects addressed in this Research Topic still represent a stimulus for future studies, their outcome aimed at providing evidence of the central position occupied by the adrenal cortex in many metabolic functions when its homeostasis is disrupted. An in-depth investigation of the mechanisms underlying these pathways will be invaluable in developing new therapeutic tools and strategies.

The adrenal gland plays essential roles in the control of body homeostasis, stress and immune responses. The adrenal cortex represents up to 90% of the gland and is specialised in the production of mineralocorticoids, glucocorticoids and adrenal androgens. This production is tightly coordinated and results from a unique zonal organisation. Although our knowledge of the molecular mechanisms controlling adrenal steroidogenesis is quite extensive, for decades, the mechanisms of adrenal cortex development, cellular homeostasis and renewal have remained elusive. The advent of new high-throughput technologies and sophisticated genetic approaches has brought tremendous progress in our understanding of how the adrenal cortex achieves and maintains its particular organisation. The aim of this Frontiers in Endocrinology Topic is to provide readers with a snapshot of our current knowledge on adrenal physiology and how deregulations of these processes result in adrenal diseases. This includes but is not limited to, basic research on adrenal development, cell lineage identification, progenitor cells, tissue renewal, control of differentiation and zonation and clinical research on the identification of disease-related genes.

Cellular and Molecular Biology of the Renin-Angiotensin System provides the first review and update of the state-of-the-art cellular and molecular aspects of the renin-angiotensin system. The book presents detailed analyses from world experts on each component of this system, including future directions. Topics range from angiotensin II receptor subtypes to processing of renin to the use of transgenic animal models for studying the role of this system in hypertension. Cellular and Molecular Biology of the Renin-Angiotensin System is essential reading for physiologists of the renin-angiotensin system, endocrinologists, cardiovascular specialists, renal physiologists, and neurobiologists.

Vitamins and Hormones serial highlights new advances in the field with this new volume presenting interesting chapters. Each chapter is written by an international board of authors. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in Vitamins and Hormones series Updated release includes the latest information on the Adrenal Gland