Abstract # 58:

Scheduled for Thursday, August 17, 2006 07:00 PM-09:00 PM: Session 8 (Regency West 1/3 ) Poster Presentation

Menstrual cycles of rhesus monkeys undergoing calorie restriction

E. D. Hutz, S. Eisele, E. Manz, R. Colman and J. Kemnitz
Wisconsin National Primate Research Center, 1220 Capitol Court, Madison, Wisconsin 53217, USA
     Calorie restriction (CR) improves many aspects of health and is thought to slow the aging process. We evaluated the effect of CR on quality and frequency of ovarian cycles in rhesus monkeys. The monkeys were on average 10 yr old at the onset of the study and have been observed for more than 10 years. Half were maintained at 70% of their individual ad libitum food intakes (R), while the remaining ate ad libitum (C). Menstrual cycles were tracked by daily monitoring of sex skin coloration and occurrence of menstruation. R weighed approximately 20% less than C and had less body fat. Subjects were considered to cycle normally if they exhibited ?75% of expected color patterns and episodes of menses (normal cycle length ? 28 days). Overall, 9 of 13 R subjects met this criterion, while only 6 of 13 C monkeys did so. When data of subjects that had repeated (e.g., diarrhea) or chronic (e.g., possible endometriosis) illness were excluded, 83% of R and 38% of C cycled normally. One of 4 C categorized as obese (obvious subcutaneous fat and typically ?1.5 kg above average body weight) had normal cyclicity; none of the R were obese. We conclude that CR helps to preserve normal cycling and that this may be due to reduced fat mass in R. Supported by NIH AG011915 and RR000167.