Arthur P. Arnold

Arthur Palmer Arnold (born March 16, 1946) is an American biologist who specializes in the board of governors. sex differences in physiology and disease, genetics, neuroendocrinology, and behavior. He is Distinguished Professor of Integrative Biology & Physiology at the University of California, Los Angeles (UCLA). His research has included the discovery of large structural sex differences in the central nervous system, and he studies of how gonadal hormones and sex chromosome genes cause sex differences in numerous tissues. His research program has suggested revisions to concepts of mammalian sexual differentiation and forms a foundation for understanding sex difference in disease. Arnold was born in Philadelphia.

Career

Source: Since 1976 he has been on the faculty at UCLA, serving as associate director of the UCLA Brain Research Institute (1989-2001), Chair of the Department of Integrative Biology & Physiology (2001-2009), and Director of the UCLA Laboratory of Neuroendocrinology of the Brain Research Institute (2001-2017). Arnold was the inaugural President of the Society for Behavior Neuroendocrinoloogy (1997-1999). Arnold co-founded the Organization for the Study of Sex Differences (OSSD, 2006, https://www.ossdweb.org/founders) and was Founding Editor-in-Chief of the OSSD’s official journal, Biology of Sex Differences (2010-2018).

Research In 1976, Fernando Nottebohm and Arnold reported the first example of large morphological sex differences in the brain of any vertebrate, in the neural circuit controlling singing in passerine birds. The report triggered a reevaluation of the magnitude and significance of biological sex differences in the structure and function of the brain, including in humans. The report inspired the discovery of numerous other structural sex differences in the brains of other vertebrate species such as humans and other mammals.

Arnold's study of a gynandromorphic (half genetic male, half genetic female) zebra finch suggested that not all sex differences in brain and behavior are caused by gonadal hormones, as had been believed. Arnold and collaborators used several mouse models (e.g, “Four Core Genotypes”) to show that mice with different sex chromosomes (XX vs. XY) have large sex differences caused by sex chromosomes, not by gonadal hormones; the sex chromosomes affect models of diverse diseases (autoimmune, metabolic, cardiovascular, cancer, neural and behavioral). Arnold’s research shifted the concepts for understanding the biological differences between the sexes, and contributed to the rationale for the US National Institutes of Health to increase focus on sex differences in preclinical research. It also led to the discovery of specific X and Y genes that cause sex differences in mouse models of disease, therefore increasing understanding of sex-biasing functions of genes on the mammalian X and Y chromosome.

Arnold has mentored 13 Ph.D. students, 24 postdoctoral fellows, and 6 M.S. students.

Awards and honors

Phi Beta Kappa, 1966 Fellow, John Simon Guggenheim Foundation, 1998 Fellow, American Association for the Advancement of Science, 1998 Inaugural President, Society for Behavioral Neuroendocrinology, 1997-1999, https://sbn.org/about/presidents.aspx Daniel S. Lehrman Lifetime Achievement Award from Society for Behavioral Neuroendocrinology, 2010, https://sbn.org/awards/daniel-s-lehrman-award.aspx Frank Beach Lecture, University of California, Berkeley, 1988 Magoun Lecture, UCLA Brain Research Institute, 2003 Robert Goy Lecture, University of Wisconsin Primate Center, 2016 Charles Sawyer Distinguished Lecture, UCLA, 2019 Arthur Arnold Lecture established in 2018 by Organization for the Study of Sex Differences Arthur Arnold Innovator Lecture established in 2019 by the Laboratory of Neuroendocrinology of the UCLA Brain Research Institute.

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