A comparison of intraperitoneal and subcutaneous temperature in freely moving rhesus macaques

Rationale: The remote measurement of body temperature with radiotelemetry provides a minimally invasive and robust method for larger experimental animals such as Old World monkeys. Existing literature encompasses data using intraperitoneal (IP) and subcutaneous (SC) implantation locations which may affect inferences about body temperature. Methods: The body temperatures of four adult male rhesus monkeys were monitored with radiotelemetry devices implanted both IP and SC in each subject. Animals were recorded at 5 min intervals for 5 months with the two transmitters being used in sequence on a weekly basis. Additional challenge with d-methamphetamine (0.32 mg/kg; i.m.) was conducted to compare the magnitude of the hyperthermic response measured IP and SC. Results: Normal daily temperatures differed by about 0.5-0.8 degrees C across implant locations with IP temperature consistently higher. The difference was consistent across the circadian cycle and when compared 1, 3 or 5 months after surgical implantation. The magnitude of the hyperthermia response to methamphetamine was about 0.75 degrees C when measured with either IP or SC implants. Conclusions: The study shows that data derived from the two major implantation locations used in existing literature are likely to be comparable. (C) 2011 Elsevier Inc. All rights reserved.