Ramesh Ramachandran, BVSc., M.S., Ph.D.
Associate Professor of Molecular Endocrinology
Research Focus
Role of adipose tissue and hypothalamic hormones on growth and reproduction
211 Henning Building
University Park, PA 16802-3501
Phone: 814-865-5202
Fax: 814-865-5691
E-mail: RameshR@psu.edu
Education
Ph.D. 1997 University of Maryland, College Park, Maryland
M.S. 1994 University of Maryland, College Park, Maryland
B.V.Sc (DVM) 1986 Madras Veterinary College, Madras, India
Program Objective
Our laboratory is interested in characterizing the influence of adipose tissue hormones on avian growth and reproduction. Adipose tissue is considered as an endocrine organ secreting a variety of hormones that are involved in the development of obesity, cardiovascular diseases, diabetes, cancer, and reproductive disorders. Our laboratory has cloned the chicken genes that encode for two adipose tissue hormones, adiponectin and visfatin. We are determining the factors that influence the biological functions and formation of multimeric forms of adiponectin and visfatin. Overall, we are interested in characterizing the physiological role of adiponectin and visfatin on carbohydrate and lipid metabolism, hypothalamic control of pituitary gland function and gonadal functions. Additionally, our laboratory is studying the neuroendocrine control of female reproduction. We are elucidating the role of a novel neuropeptide, gonadotropin-inhibitory hormone and its receptor in controlling pituitary hormone secretion and ovarian follicular maturation. We use a variety of experimental approaches to study gene and protein expression as well as post-translational modifications at the cellular, tissue and organismal levels.
Publications
Hendricks III, G. L., J. A. Hadley, S. M. Krzysik-Walker, R. Vasilatos-Younken, and R. Ramachandran. 2009. Unique profile of chicken adiponectin, a predominantly heavy molecular weight multimer, and relationship to visceral adiposity. Endocrinology 150:3092-3100.
Ocón-Grove, O. M., S. M. Krzysik-Walker, S. R. Maddineni, G. L. Hendricks III, and R. Ramachandran. 2009. NAMPT (Visfatin) in the chicken testis: Influence of sexual maturation on cellular localization, plasma levels, gene and protein expression. Submitted to Reproduction (under revision).
Maddineni, S. R., O. M. Ocón-Grove, S. M. Krzysik-Walker, G. L. Hendricks III, and R. Ramachandran. 2008. Gonadotropin-inhibitory hormone (GnIH) receptor gene is expressed in the chicken ovary: Potential role of GnIH in follicular maturation. Reproduction 135:267-274.
Maddineni, S. R., O. M. Ocón-Grove, S. M. Krzysik-Walker, G. L. Hendricks III, and R. Ramachandran. 2008. Gonadotrophin-inhibitory hormone receptor expression in the chicken pituitary gland: Potential influence of sexual maturation and ovarian steroids. J. Neuroendocrinol. 20:1078-1088.
Ocón-Grove, O. M., S. M. Krzysik-Walker, S. Maddineni, G. L. Hendricks III, and R. Ramachandran. 2008. Adiponectin and its receptors are expressed in the chicken testis: Influence of sexual maturation on testicular AdipoR1 and AdipoR2 mRNA abundance. Reproduction 136:627-638.
Krzysik-Walker, S. M., O. M. Ocón-Grove, S. R. Maddineni, G. L. Hendricks III, R. Ramachandran. 2008. Is visfatin an adipokine or myokine? Evidence for greater visfatin expression in skeletal muscle than visceral fat in chickens. Endocrinology 149:1543-1550.
Krzysik-Walker, S. M., O. M. Ocón-Grove, S. R. Maddineni, G. L. Hendricks III, and R. Ramachandran. 2007. Identification of calcitonin expression in the chicken ovary: Influence of gonadal steroids. Biol. Reprod. 77:626-635.
Maddineni, S. R., S. M. Krzysik-Walker, O. M. Ocón-Grove, G. L. Hendricks III, and R. Ramachandran. 2007. Calcitonin is expressed in the chicken pituitary gland: Influence of gonadal steroids and sexual maturation. Cell Tissue Res. 327:521-528.
Ramachandran, R., O. M. Ocón-Grove, and S. L. Metzger. 2007. Molecular cloning and tissue expression of chicken AdipoR1 and AdipoR2 complementary deoxyribonucleic acids. Dom. Anim. Endocrinol. 33:19-31.
Ocón-Grove, O. M., S. R. Maddineni, G. L. Hendricks III, R. G. Elkin, J. A. Proudman, and R. Ramachandran. 2007. Pituitary progesterone receptor expression and plasma gonadotrophin concentrations in the reproductively dysfunctional mutant restricted ovulator chicken. Dom. Anim. Endocrinol. 32:201-215.
Proszkowiec-Weglarz, M., M. P. Richards, R. Ramachandran, and J. P. McMurtry. 2006. Characterization of the AMP-activated protein kinase pathway in chickens. Comp. Biochem. Physiol., Part B. 143:92-106.
Maddineni, S. R., S. M. Metzger, O. M. Ocón, G. L. Hendricks III, and R. Ramachandran. 2005. Adiponectin gene is expressed in multiple tissues in the chicken: food deprivation influences adiponectin messenger ribonucleic acid expression. Endocrinology 146:4250-4256.
Hollon, T. R., M. J. Bek, J. E. Lachowicz, M. A. Ariano, E. Mezey, R. Ramachandran, S. R. Wersinger, P. Soares-da-Silva, Z. F. Liu, A. Grinberg, J. Drago, W. S. Young 3rd, H. Westphal, P. A. Jose, and D. R. Sibley. 2002. Mice lacking D5 dopamine receptors have increased sympathetic tone and are hypertensive. J Neurosci. 22:10801-10810.
Ramachandran, R., W. J. Kuenzel, and J. A. Proudman. 2001. Increased proliferative activity and programmed cellular death in the turkey hen pituitary gland following interruption of incubation behavior. Biol. Reprod. 64:611-618.
Weatherly, K. L., R. Ramachandran, H. Strange, K. L. Waite, B. Storrie, J. A. Proudman, and E. A. Wong. 2001. The turkey transcription factor Pit-1/GHF-1 can activate the turkey prolactin and growth hormone gene promoters in vitro but is not detectable in lactotrophs in vivo. Gen. Comp. Endocrinol. 123:244-253.
Ramachandran, R., W. J. Kuenzel, J. D. Buntin, and J. A. Proudman. 2000. Identification of growth-hormone- and prolactin-containing neurons within the avian brain. Cell Tissue Res. 299:371-383.
Ramachandran, R., R. Solow, J. A. Proudman, and W. J. Kuenzel. 1998. Identification of mammosomatotrophs in the turkey hen pituitary: increased abundance during hyperprolactinemia. Endocrinology 139:781-786.
Ramachandran, R., J. A. Proudman, and W. J. Kuenzel. 1996. Changes in pituitary somatotroph and lactotroph distribution in laying and incubating turkey hens. Gen. Comp. Endocrinol. 104:67-75.
Ramachandran, R., J. A. Proudman, and W. J. Kuenzel. 1995. Changes in pituitary somatotrophs and lactotrophs associated with ovarian regression in the turkey hen (Meleagris gallopavo). Comp. Biochem. Physiol., Part C. 112:327-334.
NCBI GenBank Publications
Metzger, S. L., and R. Ramachandran. 2005. Gallus gallus adiponectin receptor 1 (adipoR1) mRNA, complete CDs. Gen Bank Accession # DQ072275. http://www.ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=nucleotide&val=67782276.
Metzger, S. L., O. Ocón, and R. Ramachandran. 2005. Gallus gallus adiponectin receptor 2 (adipoR2) mRNA, complete CDs. Gen Bank Accession # DQ072276. http://www.ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=nucleotide&val=67782278.
Metzger, S. L., S. R. Maddineni, and R. Ramachandran. 2005. Gallus gallus adiponectin mRNA, complete CDs. Gen Bank Accession # AY838798. http://www.ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=nucleotide&val=61229306.
Maddineni, S. R., and R. Ramachandran. 2003. Gallus gallus gonadotropin-inhibiting hormone precursor, mRNA, complete CDs. GenBank Accession # AY442186 http://www.ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=nucleotide&val=38230118.
Teaching
AN SC 423, Comparative Physiology of Domestic Animals
PHYSIO 590, Animal Physiology
Graduate Students
Susan Krzysik-Walker
Anupama Tiwari
Undergraduate Students Involved in Research
Pradeep Selvam (2006-present)
Funding Sources
- United States Department of Agriculture – National Research Initiative Competitive Grants Program (Reproduction; 2004-2008)
- United States Department of Agriculture – National Research Initiative Competitive Grants Program (Growth and Nutrient Utilization; 2007-2010)
- United States Department of Agriculture – Special Grants Program (2004-2007)
- Pennsylvania Department of Agriculture (2003-2005)
Service to the Profession
- Associate Editor, Poultry Science journal (2009-2012)
- Member, Publication Committee, Biology of Reproduction journal (2007-2010)
- Ad hoc reviewer for the following refereed journals: Endocrinology, Journal of Neuroendocrinology, Comparative Biochemistry and Physiology, Poultry Science, Cell & Tissue Research, Animal Reproduction Sciences, Reproduction, and Journal of Histochemistry and Cytochemistry
- Reviewer of grant proposals for national and international funding agencies
- Member of Federal Grant Review Panels
