Temperature and adrenocortical responses in rhesus monkeys exposed to microwaves.

Abstract

To determine if the endocrine response to microwave exposure was similar in a primate to that reported for other animals, rectal temperature and plasma levels of cortisol, thyroxine (T4), and growth hormone (GH) were measured in rhesus monkeys exposed to 1.29 GHz microwave radiation. Exposures were carried out under far-field conditions with the monkey restrained in a chair. Incident power densities of 0, 20, 28, and 38 mW/cm2 were used, with corresponding specific absorption rates of 0, 2.1, 3.0, and 4.1 W/kg. Blood samples were taken hourly via an indwelling jugular venous catheter over a 24-h period before, during, and after an 8-h exposure. Rectal temperature increased an average of 0.5, 0.7, and 1.7 degrees C for the three intensities used. No changes in T1 or GH were observed. Cortisol levels were increased during exposure to 38 mW/cm2. It was concluded that the temperature and adrenocortical responses to microwave exposure of the rhesus monkey are similar to the corresponding responses of other animals.

AI evidence extraction

Main findings

Rhesus monkeys exposed to 1.29 GHz microwaves at incident power densities of 20, 28, and 38 mW/cm2 (SARs 2.1, 3.0, and 4.1 W/kg) showed average rectal temperature increases of 0.5, 0.7, and 1.7C, respectively. No changes in thyroxine (T4) or growth hormone (GH) were observed. Cortisol levels increased during exposure at 38 mW/cm2.

Outcomes measured

• Rectal temperature
• Plasma cortisol
• Plasma thyroxine (T4)
• Plasma growth hormone (GH)

Limitations

• Sample size not reported in abstract
• Exposure conditions included restraint in a chair, which could influence endocrine measures
• Cortisol increase reported only at the highest exposure level; limited detail on statistical testing in abstract

{
    "study_type": "animal",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 1290,
        "sar_wkg": null,
        "duration": "8-h exposure (with 24-h sampling before/during/after)"
    },
    "population": "Rhesus monkeys",
    "sample_size": null,
    "outcomes": [
        "Rectal temperature",
        "Plasma cortisol",
        "Plasma thyroxine (T4)",
        "Plasma growth hormone (GH)"
    ],
    "main_findings": "Rhesus monkeys exposed to 1.29 GHz microwaves at incident power densities of 20, 28, and 38 mW/cm2 (SARs 2.1, 3.0, and 4.1 W/kg) showed average rectal temperature increases of 0.5, 0.7, and 1.7\u0000C, respectively. No changes in thyroxine (T4) or growth hormone (GH) were observed. Cortisol levels increased during exposure at 38 mW/cm2.",
    "effect_direction": "mixed",
    "limitations": [
        "Sample size not reported in abstract",
        "Exposure conditions included restraint in a chair, which could influence endocrine measures",
        "Cortisol increase reported only at the highest exposure level; limited detail on statistical testing in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "rhesus monkey",
        "microwave radiation",
        "1.29 GHz",
        "rectal temperature",
        "cortisol",
        "thyroxine",
        "growth hormone",
        "SAR",
        "power density",
        "far-field exposure"
    ],
    "suggested_hubs": []
}

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