Neuroendocrine control of growth hormone in fish

CANOSA LF; CHANG JP; PETER RE

GENERAL AND COMPARATIVE ENDOCRINOLOGY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2007 vol. 151 p. 1 - 26

0016-6480

The biological actions of growth hormone (GH) are pleiotropic, including growth promotion, energy mobilization, gonadal development, appetite, and social behavior. Accordingly, the regulatory network for GH is complex and includes many endocrine and environmental factors. In Wsh, the neuroendocrine control of GH is multifactorial with multiple inhibitors and stimulators of pituitary GH secretion. In Wsh, GH release is under a tonic negative control exerted mainly by somatostatin. Sex steroid hormones and nutritional status inXuence the level of brain expression and eVectiveness of some of these GH neuroendocrine regulatory factors, suggesting that their relative importance diVers under diVerent physiological conditions. At the pituitary level, some, if not all, somatotropes can respond to multiple regulators. Therefore, ligand- and function-speciWcity, as well as the integrative responses to multiple signals must be achieved at the level of signal transduction mechanisms. Results from investigations on a limited number of stimulatory and inhibitory GH-release regulators indicate that activation of diVerent but convergent intracellular pathways and the utilization of speciWc intracellular Ca2+ stores are some of the strategies utilized. However, more work remains to be done in order to better understand the integrative mechanisms of signal transduction at the somatotrope level and the relevance of various GH regulators in diVerent physiological circumstances.