Phone: (510) 642-7136
We study how mammals orient in time, with emphasis on seasonal rhythms of reproductive physiology and behavior, hibernation, daily torpor, body weight, and adipose tissue regulation in several hamster species. Long-term interests include the role of the suprachiasmatic nucleus of the hypothalamus as a circadian pacemaker and the function of the pineal hormone melatonin as the endocrine signal through which light influences seasonal rhythms.
Graduate students typically work on projects related to the above themes and also develop independent lines of research. They frequently enter into collaborations with each other and investigators at several universities. Although our studies are laboratory based, I am also interested in supporting combined field-laboratory analyses of behavior and physiology.
Tuthill, C.R., Freeman, D.A., Butler, M.P., Chinn, T., Park, J.H. & Zucker I. Perinatal influences of melatonin on testicular development and photoperiodic memory in Siberian hamsters. J Neuroendocrin 2005, 17:483-488.
Place, N.J., Tuthill, C.R., Schoomer, E.E., Tramontin, A.D. & Zucker, I. Short Day Lengths Delay Reproductive Aging. Biol. Reprod. 2004, 71:987-992.
Kauffman, A.S., M.J. Paul, and I. Zucker. 2004. Increased heat loss affects hibernation in golden-mantled ground squirrels. American Journal of Physiology, in press.
Park, J.H., N. Takasu, M.I. Alvarez, K. Clark, R. Aimaq, and I. Zucker. 2004. Long-term persistence of male copulatory behavior in castrated and photo-inhibited Siberian hamsters. Hormones and Behavior 45:214-221.
Paul, M. J., Kauffman, A. S. & Zucker, I. Feeding schedule controls circadian timing of daily torpor in SCN-ablated Siberian hamsters. J. Biol. Rhythms 2004,19: 226-237.
Prendergast, B.J., R.J. Nelson, and I. Zucker. 2002. Mammalian seasonal rhythms: Behavior and neuroendocrine substrates. In Hormones, Brain and Behavior, ed. D.W. Pfaff, vol. 2, 93-156. Elsevier Science.
Lewis, D., D.A. Freeman, J. Dark, K.E. Wynne-Edwards, and I. Zucker. 2002. Photoperiodic control of oestrous cycles in Syrian hamsters: Mediation by the mediobasal hypothalamus. Journal of Neuroendocrinology 14:294-299.
Freeman, D.A. and I. Zucker. 2001. Refractoriness to melatonin occurs independently at multiple brain sites in Siberian hamsters. Proceedings of the National Academy of Sciences of the United States of America 98:6447-6452.