Arthur P. Arnold Explained

Arthur Palmer Arnold (born March 16, 1946) is an American biologist who specializes in 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.[1] Arnold was born in Philadelphia.

Career

Source:

Arnold received an A.B. degree in Psychology from Grinnell College (1967) and Ph.D. in Neurobiology and Behavior from The Rockefeller University (1974), where he was mentored by Fernando Nottebohm, Peter Marler, Donald Pfaff, Bruce McEwen and Hiroshi Asanuma.[2] 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.[3] [4] [5] [6] The report inspired the discovery of numerous other structural sex differences in the brains of other vertebrate species such as humans and other mammals.[7] [8] The identification of groups of cells that differed, in specific brain regions of males and females, moved the study of sexual differentiation to the cellular and molecular level, ultimately enabling the discovery of the molecular mechanisms of sexual differentiation in the brain. Arnold and co-workers uncovered hormonal control of cellular mechanisms (cell death, dendritic growth, cell growth, synapse elimination) that cause differential nervous system development in males and females.[9]

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. The two sides of the gynandromorph brain differed in the degree of masculinity of the neural song circuit, implying that sex chromosomes operated within brain cells to contribute to sex differences.[10] [11] 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,[12] [13] and contributed to the rationale for the US National Institutes of Health to increase focus on sex differences in preclinical research.[14] 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.[15] [16]

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

Awards and Honors

Notable Publications

External links

Notes and References

  1. Book: Schlinger BA . Arthur P. Arnold . Nelson . RJ . Weil . ZM . Biographical History of Behavioral Neuroendocrinology . 2022 . Springer Verlag.
  2. Mackel . R . Pavlides . C . Hiroshi Asanuma (1926-2000). . NeuroReport . 2000 . 11 . 15 . A5–6 . 11059891.
  3. Cover story: The sexes: how they differ and why . Newsweek . May 18, 1981.
  4. 1995 . Landmark Papers . Journal of NIH Research . 7 . 28–33, 52–58.
  5. News: Schmeck . Harold M. . Brains May Differ In Women And Men; Brain Differences . The New York Times . 25 March 1980 .
  6. Harding . C . Learning from Bird Brains: How the Study of Songbird Brains Revolutionized Neuroscience . Lab Animal . 2004 . 33 . 5 . 28–33. 10.1038/laban0504-28 . 15141244 . 751995 .
  7. Gorski . Roger A. . The 13th J. A. F. Stevenson Memorial Lecture Sexual differentiation of the brain: possible mechanisms and implications . Canadian Journal of Physiology and Pharmacology . June 1985 . 63 . 6 . 577–594 . 10.1139/y85-098 . 4041997 .
  8. Book: Breedlove, SM . Sexual Differentiation of the Brain and Behavior . Becker . JB . Breedlove . SM . Crews . D . Behavioral Endocrinology . 1992 . MIT Press . Cambridge MA . 39–68.
  9. Sengelaub . Dale R. . Forger . Nancy G. . The spinal nucleus of the bulbocavernosus: Firsts in androgen-dependent neural sex differences . Hormones and Behavior . May 2008 . 53 . 5 . 596–612 . 10.1016/j.yhbeh.2007.11.008 . 18191128 . 2423220 .
  10. News: Weintraub . Karen . Split-Sex Animals Are Unusual, Yes, but Not as Rare as You'd Think . The New York Times . 25 February 2019 .
  11. Ainsworth . Claire . Sex and the single cell . Nature . October 2017 . 550 . 7674 . S6–S8 . 10.1038/550S6a . 28976954 .
  12. Ainsworth . Claire . Sex redefined . Nature . 1 February 2015 . 518 . 7539 . 288–291 . 10.1038/518288a . 25693544 . 2015Natur.518..288A .
  13. Schlinger . Barney A. . Carruth . Laura . de Vries . Geert J. . Xu . Jun . State-of-the art (Arnold) behavioral neuroendocrinology . Hormones and Behavior . June 2011 . 60 . 1 . 1–3 . 10.1016/j.yhbeh.2010.11.009 . 21658535 . 9785591 .
  14. Clayton . Janine A. . Collins . Francis S. . Policy: NIH to balance sex in cell and animal studies . Nature . May 2014 . 509 . 7500 . 282–283 . 10.1038/509282a . 24834516 . 5101948 .
  15. Dance . A . Genes that escape silencing on the second X chromosome may drive disease . The Scientist . March 4, 2020 .
  16. Arnold . Arthur P. . X chromosome agents of sexual differentiation . Nature Reviews Endocrinology . September 2022 . 18 . 9 . 574–583 . 10.1038/s41574-022-00697-0 . 35705742 . 9901281 .

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Arthur P. Arnold".

Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2025, A B Cryer, All Rights Reserved. Cookie policy.