Abstract
Although urocortin is a potent inhibitor of food ingestion after peripheral administration, it was recently shown that under normal conditions this peptide crosses the blood-brain barrier (BBB) at a very slow rate. We examined whether hyperglycemia could stimulate the rate of entry (K(i)) of (125)I-urocortin into the mouse brain. In euglycemic mice, (125)I-urocortin injected iv entered the brain at a rate similar to that of the vascular marker (99m)Tc-albumin. However, injection of glucose (3 g/kg, ip) 0.5, 1, or 2 h before the (125)I-urocortin greatly increased the influx of urocortin. Without the glucose, the self-inhibition characteristic of a saturable transport system was not apparent. Self-inhibition could be demonstrated after the glucose injection, indicating activation of a transport system for urocortin that was saturable. Injection of insulin (10 U/kg, ip) 1 or 2 h before the (125)I-urocortin decreased the K(i). Thus, the entry of urocortin into brain can be activated by changes in the concentration of blood glucose, illustrating the responsiveness of the BBB to regulatory influences.
References
Mar 1, 1986·Stroke; a Journal of Cerebral Circulation·S IbayashiT Omae
Sep 11, 1995·FEBS Letters·D J BeckerS M Brichard
Oct 12, 1995·Nature·R SaladinJ Auwerx
Jan 15, 1996·FEBS Letters·H MasuzakiK Nakao
May 1, 1996·The Journal of Clinical Investigation·R B HarrisR C Bruch
Apr 16, 1996·Proceedings of the National Academy of Sciences of the United States of America·T M MizunoC V Mobbs
Sep 13, 1996·Science·M SpinaG F Koob
Jan 1, 1996·Peptides·W A BanksL M Maness
Jul 1, 1995·Neuroimmunomodulation·W A BanksR D Broadwell
May 6, 1998·Diabetes·M F SaadV Kamdar
Jun 19, 1998·Neuroreport·G N SmaginR B Harris
May 29, 1999·Gastroenterology·A AsakawaM Kasuga
Dec 29, 1999·Brain Research·A J KastinW A Banks
Jan 5, 2000·Journal of Neurochemistry·A J KastinJ E Zadina
Jul 6, 2000·Peptides·P J HopeG A Wittert
Jul 6, 2000·Peptides·A J Kastin, V Akerstrom
Jan 11, 2001·Peptides·A J KastinW Pan
Mar 31, 2001·Hormone and Metabolic Research = Hormon- Und Stoffwechselforschung = Hormones Et Métabolisme·A J KastinW Pan
May 8, 2001·Neuroendocrinology·A J Kastin, V Akerstrom
Citations
Jan 20, 2012·Journal of Neuroinflammation·Hock-Kean LiewJia-Yi Wang
Jul 31, 2003·The European Journal of Neuroscience·P SinnayahD A Denton
Dec 15, 2007·Progress in Neurobiology·Weihong Pan, Abba J Kastin
Aug 6, 2011·Neurobiology of Aging·Mickael DecressacAfsaneh Gaillard
Aug 7, 2004·Brain Research. Brain Research Reviews·Weihong Pan, Abba J Kastin
Apr 28, 2009·Progress in Neurobiology·Ivona BrasnjevicUNKNOWN European NanoBioPharmaceutics Research Initiative
Dec 16, 2006·Molecular Endocrinology·Hong TuWeihong Pan
Oct 20, 2001·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·L WangY Taché