Topic

Investigation of mechanisms of action in cells exposed to the high frequency electromagnetic fields of mobile telephone technology.
B. pineal gland

Start

01.10.2002

End

30.09.2003

Project Management

International University Bremen

Objective

Clarification shall be provided whether the function of isolated pineal organs of laboratory rodents is influenced by high frequency, a) modulated according to GSM standards or b) continuous-wave (1800 MHz) electromagnetic fields. The hormone melatonin is produced according to the diurnal rhythm in the pineal gland. This phylogenetic old hormone is involved in a row of physiologic functions, e.g. the circadian rhythm. It has also been postulated that melatonin acts as a free radical scavenger to prevent cancer or, at least, slow down its growth. In order to reach a definite conclusion of whether or not cellular fields have an affect on the production of this hormone, the effects of diurnal rhythm have to be excluded. This is only possible in experiments using isolated pineal organs (in vitro).

Results

Isolated pineal organs of Djungarian Hamsters were exposed for 7 h to a 1800 MHz continous-wave (cw) or pulsed GSM-modulated electromagnetic at signal at specific absorption rates (SAR) of 0 (sham-exposure), 0.008, 0.08, 0.8 and 2.7 W/kg. Perifusate samples were collected every hour, and melatonin concentrations were measured by a specific radioimmunoassay. Experiments were performed in a "blinded" fashion, i.e. the researchers do not know which samples are exposed to RF-radiation and which are sham-exposed controls. This ensures an unbiased analysis of the data.

While no effects of RF-EMF exposure were seen at 0.008 and 0.08 W/kg, both types of signal (cw and GSM) significantly enhanced melatonin release at 0.8 W/kg SAR, while at 2.7 W/kg SAR, melatonin levels were elevated in the cw, but suppressed in the GSM-exposed pineal glands. The temperature rise of approximately 1.2^oC at 2.7 W/kg SAR indicates an unphysiological thermal effect.

The final report is available as PDF-file (1260 kB) in German.

References

• Sukhotina et al. (2006): 1800 MHz electromagnetic field effects on melatonin release from isolated pineal glands, J. Pineal Res. 40: 86 - 91

Conclusion:

Since no effects were observed at 0.008 and 0.08 W/kg (the recommended whole-body SAR limit for the general public) and since exposure to 0.8 W/kg leads to an enhanced production of melatonin, the results of the study do not support the "melatonin hypothesis" according to which non-thermal RF-EMD exposure should lead to a suppression of melatonin synthesis.

Whether the increased melatonin production detected at 0.8 W/kg is relevant for human exposure scenarios depends on the SAR values and the temperature rise, which can be caused under "worst case" conditions by a mobile phone. In the in vitro system used in this study, a temperature rise of 0.5-0.6^oC was observed. Since the human pineal organ is situated in the centre of the brain, most of the currently published data do not support the hypothesis of such a temperature rise in vivo. The results from studies carried out in the German Mobile Telecommunication research programme, e.g. the study "Investigation of age-dependent effects of high frequency electromagnetic fields based on relevant biophysical and biological parameters" shall help to answer this question.