• Title Professor Emerita of Biology
  • Education PhD, Rutgers University, 1964
  • Phone 617-353-8980
  • Area of Interest neuroendocrinology, reproductive and developmental endocrinology, estrogen biosynthesis, estrogen receptor mediated actions and gene regulation, environmental endocrine disruption
  • CV


Research in this laboratory focuses on the biosynthesis and actions of estradiol. In tissues where aromatase (cytochrome P450 aromatase, estrogen synthetase) and estrogen receptors (ER) are colocalized, estradiol has discrete, local actions (paracrine, autocrine) that differ qualitatively and quantitatively from those exerted by the circulating hormone (endocrine). We are investigating the structure, function, regulation, and evolution of genes encoding aromatase (Cyp19) and ER (Esr) in neural tissues and the physiological and developmental consequences of estrogen formation in specific cells and circuits of the brain and retina. A component of the project is to define the role of different ER genes and splice variants in mediating estrogen actions in different tissue types and developmental stages; determine mechanisms by which estrogen-like environmental chemicals disrupt normal endocrine and neuroendocrine processes of physiology and development; and identify physiological, genetic, and epigenetic adaptations in estrogen signaling pathways that are driven by long term, multigenerational exposure of organisms to estrogenic environments. We use a wide range of animal models from fish to mammals and rely primarily on methods of cell biology (tissue culture, light and electron microscopy, image analysis), protein and steroid biochemistry (enzymology, SDS-PAGE and immunoblot analysis), and molecular biology (cDNA and gene cloning and PCR-based methods of RNA & DNA analysis).

Selected Publications

  • Griffin LB, January K, Ho K, Cotter K, Callard GV (2013) Morpholino-mediated knockdown of genes encoding estrogen receptor-a, -ba and –bb in zebrafish embryos reveals differential regulation of estrogen responsive target genes. Endocrinology 154: 4158-4169 (doi10.1210/en2013-1446).
  • Cotter KA, Yershov A, Novillo A, Callard GV (2013) Multiple structurally distinct ERa mRNA variants in zebrafish are differentially expressed by tissue type, stage of development and estrogen exposure. Gen Comp Endocrinol 194:217-229.
  • Callard GV, Greytak SR, Novillo A, Cotter KA, Meyer R (2012) Brain Aromatase in Fishes. In: Balthazart J, Ball G (eds),  Brain Aromatase, Estrogens and Behavior, Oxford Univ Press, pp. 2-42.
  • Callard GV, Tarrant A, Novillo A, Yacci P, Ciaccia L, Vajda S, Chuang G-Y, Kozakov D, Greytak SR, Sawyer S, Hoover C, Cotter K (2011) Evolutionary origins of the estrogen signaling system: insights from amphioxus. J Steroid Biochem Mol Biol 127: 176-188.
  • Greytak SR, Tarrant A, Nacci D, Hahn ME, Callard GV (2010) Estrogen responses in killifish (Fundulus heteroclitus) from polluted and unpolluted environments are site- and gene-specific. Aquatic Toxicol.99(2): 291–299.
  • McCurley A, Callard GV (2008) Characterization of housekeeping genes in zebrafish: male-female differences and effects of tissue type, developmental stage and chemical treatment. BMC Molecular Biology 9:102-114.
  • Kishida M, Callard GV (2001) Distinct cytochrome P450 aromatase isoforms in zebrafish (Danio rerio) brain and ovary are differentially programmed and estrogen regulated during early development.Endocrinology. Feb; 142(2), 740-50.
  • Tchoudakova A, Callard GV (1998) Identification of multiple Cyp19 genes encoding different cytochrome P450 aromatase isozymes in brain and ovary. Endocrinology 139, 2179-2189.

Courses Taught:

  • BI 554 Neuroendocrinology
  • BI 111 Brain, Hormones and Behavior

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