ECE2018 Symposia Ups and downs of hypothalamo-pituitary hormones (3 abstracts)
France.
A current challenge in physiology/pathology is translating cell-transduction processes identified in vitro into the living organism, especially where cell-cell interaction and dynamics have key functional roles. The pituitary gland, regulating a diverse range of essential physiological functions, exemplifies this challenge: stimulation from the brain is relayed as variable hormone pulses (the hypothalamic-pituitary (HP) system), which are decoded by peripheral organs into differential effects. The stimulatory inputs and intermediary/final secretory output of the HP system have impressive differences in time-scale and the number of cells involved: a few thousand hypothalamic neurons with signalling frequencies in the millisecond range drive hundreds of thousands of pituitary cells to secrete hormone pulses over a period of hours. These features of the HP system are conserved across a diverse range of mammals. However, how pituitary networks transform hypothalamic inputs into hormone pulses in vivo was unknown. Using newly-developed techniques for imaging and manipulating cells in vivo, namely in freely-behaving mouse models, we unveiled how the pituitary somatotroph network translates its hypothalamic inputs into GH pulses in the bloodstream.