Cell Networks in Endocrine/Neuroendocrine Gland Function

Abstract

Reproduction, growth, stress and metabolism are determined by endocrine/neuroendocrine systems that regulate circulating hormone concentrations. All these systems generate rhythms and changes in hormone pulsatility observed in a variety of pathophysiological states. Thus, the output of endocrine/neuroendocrine systems must be regulated within a narrow window of effective hormone concentrations but must also maintain a capacity for plasticity to respond to changing physiological demands. Remarkably most endocrinologists still have a 'textbook' view of endocrine gland organization which has emanated from 20 th century histological studies on thin 2D tissue sections. However, 21 st century technological advances, including indepth 3D imaging of specific cell types have vastly changed our knowledge. We now know that various levels of multi-cellular organization can be found across different glands, that organizational motifs can vary between species and can be modified to enhance or decrease hormonal release. This review focuses on how the organization of cells regulates hormone output using three endocrine/neuroendocrine glands that present different levels of organization and complexity: the adrenal medulla, with a single neuroendocrine cell type; the anterior pituitary, with multiple intermingled cell types; and the pancreas with multiple intermingled cell types organized into distinct functional units. We give an overview of recent methodologies that allow the study of the different components within endocrine systems, and particularly their temporal and spatial relationships. We believe the emerging findings about network organization, and its impact on hormone secretion, are crucial to understanding how homeostatic regulation of endocrine axes is carried out within endocrine organs themselves.

Adaptive remodeling of rat adrenomedullary stimulus-secretion coupling in response to a chronic hypertensive environment

“…Adrenal CA secretion and more generally the adrenomedullary tissue function are controlled by the coordination of interconnected and complex pathways 12 . ge initial incoming command comes from the sympathetic nervous system that releases mainly acetylcholine (ACh) but also neuropeptides (PACAP, VIP...) at splanchnic nerve terminals synapsing onto chromaffin cells 13,14 .…”

L’hypophyse dévoilée : du couplage stimulation-sécrétion aux réseaux cellulaires câblant la glande

“…C'est là que l'esprit d'ouverture de Mme Tixier-Vidal m'a montré la voie, en combinant l'expertise de son laboratoire sur des cellules hypophysaires en culture à celle du laboratoire d'électrophysiologie de Jean-Didier Vincent et Bernard Dufy en vue de décrypter des premières signatures de ce couplage stimulation-sécrétion dans des cellules endocrines de l'hypophyse, glande « maîtresse » de notre organisme (Dufy et al, 1979). Cet esprit d'ouverture et de communication dont Mme Tixier-Vidal fut sans conteste une pionnière pour la recherche en endocrinologie/neuroendocrinologie a été le ferment des approches multidisciplinaires, décrites brièvement ci-dessous, qui ont permis d'une part, d'identifier les grandes étapes du couplage stimulation-sécrétion et d'autre part, d'élaborer une vision nouvelle de l'organisation et du fonctionnement intégré de l'hypophyse (pour des revues exhaustives voir : Le Tissier et al, 2017 ;Guérineau et al, 2022).…”