Do long-term glucocorticoid treatments induce behavioral rhythm disturbances in rats?
To examine the influences of a long-term glucocorticoid treatment on behavioral rhythm in rats, I measured motor activity, feeding and drinking, and body temperature in rats that had been treated with corticosterone over a long term, by means of an automatic behavioral measurement system combined with a telemetry system. Either a cholesterol (100 mg, as a control) or corticosterone (100 mg) bead was implanted subcutaneously in rats for 3 months, and the effects of the treatments on behavioral parameters were evaluated 2 to 4 months after the termination of the treatments. Corticosterone did not significantly change daily rhythms of all four parameters and mean values of them. However, three out of six corticosterone-treated rats appeared to show higher the mesor of motor activity compared with the control group. The present study demonstrates that a long-term glucocorticoid treatment does not impair behavioral daily rhythm, then suggests that a long-term glucocorticoid exposures could not damage the endogenous clock of the brain, that is, the suprachiasmatic nucleus.
Endo
Y
Y
Department of Physiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan. endoyuta@med.uoeh-u.ac.jp
D000375:Aging / Q000187:drug effects* / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001831:Body Temperature / Q000187:drug effects*; D002940:Circadian Rhythm / Q000187:drug effects*; D005938:Glucocorticoids / Q000009:adverse effects*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar
D005938:Glucocorticoids