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Cellular in vivo imaging reveals coordinated regulation of pituitary microcirculation and GH cell network function.
Lafont C., Desarménien M. G., Cassou M., Molino F., Lecoq J. et al
Proceedings of the National Academy of Sciences of the United States of America 107, 9 (2010) 4465-70 - http://hal.archives-ouvertes.fr/hal-00496016
Sciences du Vivant/Bio-Informatique, Biologie Systémique
Informatique/Bio-informatique
Cellular in vivo imaging reveals coordinated regulation of pituitary microcirculation and GH cell network function.
Chrystel Lafont1, Michel G Desarménien1, Mathieu Cassou1, François Molino1, Jérôme Lecoq2, David Hodson1, Alain Lacampagne3, Gerard Mennessier ()4, Taoufik El Yandouzi1, Danielle Carmignac, Pierre Fontanaud1, Helen Christian, Nathalie Coutry1, Marta Fernandez-Fuente, Serge Charpak2, Paul Le Tissier, Iain C A F Robinson, Patrice Mollard1
1 :  IGF - Institut de génomique fonctionnelle
http://www.igf.cnrs.fr
CNRS : UMR5203 – INSERM : U661 – Université Montpellier I – Université Montpellier II - Sciences et techniques
141, Rue de la Cardonille 34094 MONTPELLIER CEDEX 5
France
2 :  NNM - Neurophysiologie et nouvelles microscopies
http://www.physio.espci.fr
CNRS : IFR95 – INSERM : U603 – Université Paris V - Paris Descartes
45, rue des Saints Pères 75007 PARIS
France
3 :  Physiopathologie cardiovasculaire
INSERM : U637 – IFR3 – Université Montpellier I
Hopital Arnaud de Villeneuve 171, Avenue du Doyen Gaston Giraud 34295 MONTPELLIER CEDEX 5
France
4 :  LPTA - Laboratoire de Physique Théorique et Astroparticules
http://www.lpta.in2p3.fr/
CNRS : UMR5207 – IN2P3 – Université Montpellier II - Sciences et techniques
Bât 13- 1er Et. - CC 070 Place Eugène Bataillon 34095 MONTPELLIER CEDEX 5
France
Growth hormone (GH) exerts its actions via coordinated pulsatile secretion from a GH cell network into the bloodstream. Practically nothing is known about how the network receives its inputs in vivo and releases hormones into pituitary capillaries to shape GH pulses. Here we have developed in vivo approaches to measure local blood flow, oxygen partial pressure, and cell activity at single-cell resolution in mouse pituitary glands in situ. When secretagogue (GHRH) distribution was modeled with fluorescent markers injected into either the bloodstream or the nearby intercapillary space, a restricted distribution gradient evolved within the pituitary parenchyma. Injection of GHRH led to stimulation of both GH cell network activities and GH secretion, which was temporally associated with increases in blood flow rates and oxygen supply by capillaries, as well as oxygen consumption. Moreover, we observed a time-limiting step for hormone output at the perivascular level; macromolecules injected into the extracellular parenchyma moved rapidly to the perivascular space, but were then cleared more slowly in a size-dependent manner into capillary blood. Our findings suggest that GH pulse generation is not simply a GH cell network response, but is shaped by a tissue microenvironment context involving a functional association between the GH cell network activity and fluid microcirculation.
Anglais

Proceedings of the National Academy of Sciences of the United States of America
non spécifiée
Articles dans des revues avec comité de lecture
02/03/2010
107
9
4465-70

Animals – Growth Hormone: metabolism – Male – Mice – Inbred C57BL – Transgenic – Microcirculation – Pituitary Gland: blood supply – cytology – metabolism
LPTA:10-045