INSTITUTO TECNOLOGICO DE CHASCOMUS
Unidad Ejecutora - UE
Multimodal hypothalamo-hypophysial communication in the vertebrates
VANCE L. TRUDEAU; GUSTAVO M. SOMOZA
GENERAL AND COMPARATIVE ENDOCRINOLOGY
ACADEMIC PRESS INC ELSEVIER SCIENCE
Lugar: Amsterdam; Año: 2020 vol. 293
The vertebrate pituitary is arguably one of the most complex endocrine glands from the evolutionary, anatomical and functional perspectives. The pituitary plays a master role in endocrine physiology for the control of growth, metabolism, reproduction, water balance, and the stress response, among many other key processes. The synthesis and secretion of pituitary hormones are under the control of neurohormones produced by the hypothalamus. Under this conceptualframework, the communication between the hypophysiotropic brain and the pituitary gland is at the foundation of our understanding of endocrinology. The anatomy of the connections between the hypothalamus and the pituitary glandhas been described in different vertebrate classes, revealing diverse modes of communication together with varying degrees of complexity. In this context, the evolution and variation in the neuronal, neurohemal, endocrine andparacrine modes will be reviewed in light of recent discoveries, and a re-evaluation of earlier observations. There appears to be three main hypothalamo-pituitary communication systems: 1. Diffusion, best exemplified by theagnathans; 2. Direct innervation of the adenohypophysis, which is most developed in teleost fish, and 3. The median eminence/portal blood vessel system, most conspicuously developed in tetrapods, showing also considerable variationbetween classes. Upon this basic classification, there exists various combinations possible, giving rise to taxon and species-specific, multimodal control over major physiological processes. Intrapituitary paracrine regulation and communication between folliculostellate cells and endocrine cells are additional processes of major importance. Thus, a more complex evolutionary picture of hypothalamo-hypophysial communication is emerging. There is currently little direct evidence to suggest which neuroendocrine genes may control the evolution of one communication system versus another. However, studies at the developmental and intergenerational timescales implicate several genes inthe angiogenesis and axonal guidance pathways that may be important.