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Tumor-inhibiting activity in the rat pineal gland displays a circannual rhythm
H Bartsch1, C Bartsch, D Gupta
1Department of Diagnostic Endocrinology, University Children's Hospital, Tübingen, Germany.
Abstract:
The aim of this study was to investigate whether the tumor-inhibiting activity present in the rat pineal gland undergoes seasonal fluctuations as do other pineal substances. Crude ethanol extracts of rat pineal glands were tested for tumor-inhibiting activity in an in vitro microbioassay using human erythroleukemia cells which could not be inhibited by melatonin. Highest activity was detected in summer and least inhibition and even stimulation were observed in winter. There were no differences in activity between animals of different age, sex, or strain. Therefore, season seems to be the factor that exerts the most important influence on the content of tumor-inhibiting activity in the rat pineal gland. Correlation with seasonality in the occurrence of cancer is discussed.
Insights
Rat pineal gland extracts show seasonal tumor-inhibiting activity, with highest potency in summer. This suggests seasonality influences the gland's anti-cancer properties, impacting cancer occurrence.
Area of Science:
- Oncology
- Endocrinology
- Chronobiology
Background:
- The rat pineal gland produces substances with potential anti-cancer effects.
- Pineal gland activity, including melatonin production, is known to exhibit seasonal variations.
Purpose of the Study:
- To determine if tumor-inhibiting activity in rat pineal gland extracts fluctuates seasonally.
- To investigate the influence of season on the anti-cancer properties of pineal gland extracts.
Main Methods:
- Crude ethanol extracts from rat pineal glands were prepared.
- Tumor-inhibiting activity was assessed using an in vitro microbioassay with human erythroleukemia cells.
- Activity was compared across different seasons, ages, sexes, and rat strains.
Main Results:
- Tumor-inhibiting activity was highest in extracts from summer.
- The lowest inhibition, and even stimulation of cell growth, was observed in winter extracts.
- No significant differences in activity were found based on animal age, sex, or strain.
Conclusions:
- Seasonal fluctuations significantly influence the tumor-inhibiting activity of the rat pineal gland.
- Seasonality appears to be the primary factor affecting the anti-cancer potential of pineal gland extracts.
- Findings suggest a potential correlation between pineal gland activity, seasonality, and cancer occurrence.