Seasonal Fluctuations of Hydroxy-Indole Levels in the Pineal Body of the Northern Fur Seal (Callorhinus ursinus)
M.C. Keyes1, BA, DVM; R.J. Wurtman2, MD; C.A. Elden3, MD
1Marine Mammal Biological Laboratory, National Marine Fisheries Service, Seattle, WA; 2Department of Nutrition and Food Science, Massachusetts Institute of Technology, Cambridge, MA; 3Woodinville, WA
Levels of hydroxy-indole-o-methyl transferase (HIOMT) and serotonin in the pineal bodies of 108 multiparous, primiparous, and nulliparous female fur seals are compared during March and May near latitude 47 (Washington Coast), and during July and November near latitude 55 30' (Pribilof Islands). Similar comparisons are made for 13 immature male fur seals during March and July. Three groups of multiparous female fur seals were subjected to controlled lighting. The probable role of the pineal body in the regulation of the fur seal reproductive cycle is discussed.