Growth and Development of Rhesus Monkeys Exposed to ELF (Extremely Low Frequency) Electric and Magnetic Fields during the First 54 Months of Life.

Abstract : Thirty rhesus monkeys (Macaca mulatta), 17 males and 13 females, were exposed to 22 hours per day, 7 days per week, from 1 to 54 months of age to extremely low frequency (ELF) electric and magnetic fields. A second group of 30 animals served as controls. The project was designed to produce fields similar to, but stronger than those associated with the Navy's ELF communications system. The field parameters (0.2mT and 20 V/m at a frequency modulated between 72 and 80 Hz) were the same as those used in an earlier study in which enhanced growth rate occurred in pubescent male rhesus monkeys. The biological endpoints measured included body weight, bone growth, steroid hormones, hematology, and menstrual cycle data. No differences between exposed and control groups were observed prior to puberty. During puberty, body weight, bone growth, the age at which menarche was observed, and the progressive development of the mature endocrine rhythms of the menstrual cycle were all similar for both the exposed and control female monkeys. Body weight curves of the exposed and control males began to grow faster than the controls, and continued to diverge slowly through approximately 42 months of age. The growth curve separation narrowed, however, in the last 12 months of the study. The differences in growth were not statistically significant. No significant differences in mean testosterone levels of male monkeys were observed.