This Article Full Text Full Text (PDF) All Versions of this Article: jhc.7A7214.2007v1 55/10/1059    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Crane, C. Articles by Childs, G. V. Search for Related Content PubMed PubMed Citation Articles by Crane, C. Articles by Childs, G. V. Social Bookmarking                      What's this?

Fasting and Glucose Effects on Pituitary Leptin Expression: Is Leptin a Local Signal for Nutrient Status?

Christopher Crane, Noor Akhter, Brandy W. Johnson, Mary Iruthayanathan, Farhan Syed, Akihiko Kudo, Yi-Hong Zhou and Gwen V. Childs

Department of Neurobiology and Developmental Sciences, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas (CC,NA,BWJ,FS,GVC); Department of Anatomy, Kyorin University School of Medicine, Tokyo, Japan (AK); Division of Endocrinology, Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, Iowa (MI); and Department of Neurological Surgery, University of California Irvine, Orange, California (Y-HZ)

Correspondence to: Gwen V. Childs, PhD, Department of Neurobiology and Developmental Sciences, College of Medicine, University of Arkansas for Medical Sciences, 4301 W. Markham #510, Little Rock, AR 72205. E-mail: childsgwenv{at}uams.edu

Leptin, a potent anorexigenic hormone, is found in the anterior pituitary (AP). The aim of this study was to determine whether and how pituitary leptin–bearing cells are regulated by nutritional status. Male rats showed 64% reductions in pituitary leptin mRNA 24 hr after fasting, accompanied by significant (30–50%) reductions in growth hormone (GH), prolactin, and luteinizing hormone (LH), and 70–80% reductions in target cells for gonadotropin-releasing hormone or growth hormone-releasing hormone. There was a 2-fold increase in corticotropes. Subsets (22%) of pituitary cells coexpressed leptin and GH, and <5% coexpressed leptin and LH, prolactin, thyroid-stimulating hormone, or adrenocorticotropic hormone. Fasting resulted in significant (55–75%) losses in cells with leptin proteins or mRNA, and GH or LH. To determine whether restoration of serum glucose could rescue leptin, LH, and GH, additional fasted rats were given 10% glucose water for 24 hr. Restoring serum glucose in fasted rats resulted in pituitary cell populations with normal levels of leptin and GH and LH cells. Similarly, LH and GH cells were restored in vitro after populations from fasted rats were treated for as little as 1 hr in 10–100 pg/ml leptin. These correlative changes in pituitary leptin, LH, and GH, coupled with leptin's rapid restoration of GH and LH in vitro, suggest that pituitary leptin may signal nutritional changes. Collectively, the findings suggest that pituitary leptin expression could be coupled to glucose sensors like glucokinase to facilitate rapid responses by the neuroendocrine system to nutritional cues. (J Histochem Cytochem 55:1059–1073, 2007)

Key Words: leptin • growth-stimulating hormone • corticotropes • prolactin • luteinizing hormone • gonadotropin-releasing hormone • growth hormone releasing hormone

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

Guidelines | Subscriptions | About | exPRESS - Current - Archive | Business Information | Contact

The Journal of Histochemistry & Cytochemistry is owned, published, and licensed by The Histochemical Society © 2007