Alvin M. Matsumoto, M.D.
Associate Professor, Department of Medicine
Chief, Gerontology; Associate Director, Geriatric Research, Education and Clinical Center; Associate Chief of Staff for Geriatrics and Extended Care, Department of Veterans Affairs, Puget Sound Health Care System
We perform studies both in humans and animal models to investigate the hormonal control of testis function and alterations neuroendocrine and hormonal regulation of the reproductive axis with aging.
We have had a long-standing interest in mechanisms of hormonal regulation of spermatogenesis and testicular Sertoli and Leydig cell function in humans. We continue studies aimed at defining the relative physiological roles of the pituitary gonadotropin hormones, follicle-stimulating hormone and luteinizing hormone, in the control of sperm production, and Sertoli and Leydig cell secretion of inhibin and sex steroids respectively in men. We also continue studies aimed at optimizing hormonal approaches to reversibly suppress spermatogenesis in normal men with the practical goal of developing a safe and effective male contraceptive. These clinical studies utilize administration of testosterone alone or in combination with progestagens or gonadotropin-releasing hormone analogs in normal men to experimentally induce gonadotropin deficiency and suppress testicular function, and replacement paradigms using either purified or recombinant human gonadotropins.
We also remain interested in the neuroendocrine and hormonal mechanisms of male reproductive senescence and associated age-related alterations in food intake, body composition and androgen target organs. These studies utilize an animal model, the male Brown Norway rat, that we have characterized and shown to exhibit both hypothalamic-pituitary and testicular dysfunction with aging similar to that found in aging men. In situ hybridization histochemistry, and immunoassays and assays employing high performance liquid chromatography with electrochemical detection for neuropeptide and neurotransmitter measurements in microdissected brain regions are used to examine age-related alterations in brain neuropeptide and neurotransmitter gene expression and hormonal regulation in this animal model.
Publications:
Bebb RA, Anawalt BD, Christensen RB, Paulsen CA, Bremner WJ, Matsumoto AM. (1996) Combined administration of levonorgestrel and testosterone induces more rapid and effective suppression of spermatogenesis that testosterone alone: a promising male contraceptive approach. Journal of Clinical Endocrinology and Metabolism 81:757-762.
Matsumoto AM. Spermatogenesis. In: EY Adashi, JA Rock, Z Rosenwaks (eds). (1996) Reproductive Endocrinology, Surgery and Technology. Lippincott-Raven Publishers, Philadelphia, p. 359-384.
Gruenewald DA, Naai MA, Marck BT, Matsumoto AM. (1994) Age-related decrease in neuropeptide Y gene expression in the arcuate nucleus of the male rat brain is independent of testicular feedback. Endocrinology 134:2383-2389.
Gruenewald DA, Naai MA, Hess DL, Matsumoto AM. (1994) The Brown Norway rat as a model for male reproductive aging: evidence for both primary and secondary testicular failure. Journal of Gerontology: Biological Sciences 49:B42-B50.
