Time course and role of the pineal gland in photoperiod control of innate immune cell functions in male Siberian hamsters

• Published in: Journal of neuroimmunology Vol. 161; no. 1; pp. 137 - 144
• Main Authors: Yellon, Steven M., Kim, Kiam, Hadley, Allison R., Tran, Long T.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2005
• Subjects: Analysis of Variance; Animals; Circadian; Cricetinae; Cytolysis; Cytotoxicity Tests, Immunologic - methods; Fluoresceins - metabolism; Killer Cells, Natural - immunology; Killer Cells, Natural - radiation effects; Light; Male; Melatonin; Organ Size - physiology; Organ Size - radiation effects; Phagocyte; Phagocytes - immunology; Phagocytes - radiation effects; Phodopus; Photoperiod; Pineal Gland - cytology; Pineal Gland - immunology; Reproduction; Testis - physiology; Testis - radiation effects; Time Factors; Cytolysis; Reproduction; Melatonin; Circadian; Phagocyte
• ISSN: 0165-5728; 1872-8421
• DOI: 10.1016/j.jneuroim.2004.12.008

The time course of select phagocyte and natural killer activities to short days was determined. In advance of testes regression, circulating granulocyte and monocyte cell numbers in hamsters decreased while lymphocyte numbers increased; phagocytosis and oxidative burst activity also decreased. To determine whether the pineal gland influences these innate immune cell functions, hamsters were exposed to constant light. Photoperiod control of testes weight and basal oxidative burst activity was abolished by treatment with constant light; other phagocyte activities and leukocyte proportions in circulation were not affected. The findings suggest that photoperiod and pineal gland function may regulate certain innate immune activities.