Melatonin concentrations in pineal organ culture are suppressed by sera from tumor-bearing mice.
The melatonin rhythm is significantly attenuated in a wide range of human and animal tumor types. Since surgical removal of the tumor has been shown to restore this rhythm, we hypothesized that a plasma borne tumor-associated factor (TAMF) could be responsible. A population of mice were injected with tumor cells and sequentially killed and bled over the following 9 days, i.e., to the maximal state of tumor growth. Pooled serum from the different collection days was added to an established pineal organ culture system, and melatonin concentrations measured. A highly significant correlation between melatonin concentrations and the stage of tumor growth was seen with maximal inhibition occurring at day 9 (P < 0.01). These findings support our hypothesis and may help to explain the mechanism whereby melatonin rhythmicity is suppressed in cancer patients.
Department of Physical Sciences, Wellcome Research Laboratories, Kent, U.K.
A M
AM
Leone
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D
Skene
D000818:Animals; D001685:Biological Factors / Q000494:pharmacology*; D007942:Leukemia, Experimental / Q000097:blood*; D008297:Male; D008550:Melatonin / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051379:Mice; D009924:Organ Culture Techniques; D010870:Pineal Gland / Q000187:drug effects / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D014407:Tumor Cells, Cultured
D001685:Biological Factors; D008550:Melatonin