Rutgers New Jersey Agricultural Experiment Station | Rutgers Home Search Rutgers

NJAES Faculty Expertise Database

Dipak Sarkar Dipak Sarkar
Professor
 Animal Sciences
Endocrine Research Facility
New Brunswick, NJ 08901
Phone: 732-932-1529
Fax: 732-932-6996
Email: sarkar@aesop.rutgers.edu
Website: www.anisci.rutgers.edu/faculty/sarkar/dipak-k-sarkar.html

Expertise Summary
  The goal of my research program is to understand how the brain (hypothalamus and the pituitary) controls various endocrine functions including reproduction, and how this regulatory process alters during the pathogenesis and alcohol abuse. The hypothalamus is a part of the central nervous system and contains a large number of hormone-secreting neurons. The hormones secreted from the hypothalamus are involved in the regulation of the function of both nervous and endocrine systems. We and others have shown that hypothalamic endorphin plays an important regulatory role in reproduction, memory and analgesia and the anxiolytic effect of alcohol intoxication. We are studying how alcohol induces programmed neuronal death, and alters calcium channels, membrane phospholipids and cyclic AMP production in ß-endorphin neurons to regulate the transcription of pro-ß-endorphin genes and the secretion of ß-endorphin. We believe that our work should increase understanding the neurobiology of alcohol addiction. In addition to endorphin, the neurons of the hypothalamic arcuate nucleus secrete a large amount of homones that regulate the function of a group of cells (called lactotropes) in the pituitary gland. Lactotropes secrete prolactin hormone which is essential for maintaining reproduction and lactation. We have shown that, during aging and under chronic estrogen administration as well as chronic alcohol consumtion in rats, there is an increase in growth of lactotropes and an increase in the incidence of prolactin-secreting tumors (prolactinomas). Extensive experimental work has uncovered the roles of estrogen receptors and various growth regulatory peptides in estradiol action on lactotropes. However, it is only recently that we are beginning to gain insight into how these growth factors interact to regulate estradiol action on lactotrope cell proliferation. Recent studies have identified the regulatory role of TGF-ß related peptides in estradiol action on lactotropes. Additionally, these studies unveiled that TGF-ß and FGF interact to facilitate the communication between lactotropes and folliculostellate cells that is necessary for the mitogenic action of estradiol. How steroids and TGF-ß interact to control cell growth and transformation is currently under investigation. Furthermore, we are evaluating TGF-ß genes' expression during cell differentiation and tumor progression, and the role of various forms of TGFß in apoptotic cell death and estrogen-induced cell transformation in the pituitary. This work should increase our understanding the etiology of prolactin-secreting pituitary tumors and ultimately controlling these tumors in humans.

Research Projects
  • STRESS AND MULTIPLE BRAIN NEUROPEPTIDES: IN VIVO RELEASE AND PEPTIDE BIOSYNTHESIS
  • Circadian control of NK cell function
  • Fetal Programming of Pituitary Diseases
  • ALCOHOL AND HYPERPROLACTINEMIA

    • Selected Publications
    -ß3 stimulates lactotropic cell growth by increasing b-FGF from folliculo-stellate cells.
      Journal: Endocrinology
     Authors: Hentges S, Sarkar D.K
    Volume: 141    Pages: 859-867
    Date Published: 2000
    Differential regulation by estrogens of growth and prolactin synthesis in pituitary cells suggests only a small pool of estrogen receptors is required for growth.
      Journal: Proceeding National Academy of Science USA
     Authors: Chun T-Y, Gregg D, Sarkar DK and Gorski J
    Volume: 95    Pages: 2325-2330
    Date Published: 1998
    Opposing actions of two TGF-ß isoforms on pituitary lactotropic cell proliferation.
      Journal: Endocrinology
     Authors: Hentges S, Pastorcic M, De A, Boyadjieva N, Sarkar D.K
    Volume: 141    Pages: 1528-1535
    Date Published: 2000

    Students
    Cuiping Chen Post Doc
    Sonia Cohen Graduate
    George H. Cook Graduate
    Madhavi Dokur Graduate
    Hemanta Koley Post Doc
    Peter Kuhn Post Doc
    Soichi Ominzu Post Doc
    Kristina Willoeghby Graduate

     

    -----