Abstract # 154:

Scheduled for Friday, August 18, 2006 07:00 PM-09:00 PM: Session 17 (Regency West 1/3 ) Poster Presentation

Calorie restriction, phase of the menstrual cycle and glucose regulation

E. C. Manz, E. Hutz, S. Eisele, R. Colman and J. Kemnitz
Wisconsin National Primate Research Center, 1220 Capitol Court, Madison, WI 53703, USA
     Ovarian hormones estrogen (E) and progesterone (P) are known to influence several metabolic processes, including regulation of glycemia. Previous studies have shown that in the luteal phase of the ovarian cycle, characterized by high P and low E, there is decreased insulin sensitivity (SI), whereas the follicular phase (high E, low P) is associated with increased SI. We have studied 30 (initially) female rhesus monkeys for 10 years (individually housed), with regular assessments of food intake, body composition, menstrual cycles (by sex skin coloration and observation of menstruation), and SI (by the minimal model); half were maintained at 70% of their individual ad libitum food intakes (R) while the remaining were fed ad libitum (C). Dietary restriction has been shown to enhance SI. Outcome variables of SI, fasting plasma insulin concentration, acute insulin response to glucose, and glucose tolerance were compared for the early follicular, periovulatory, mid-luteal, and late luteal phases using simple regression modeling, controlling for endometriosis, body fat and dietary treatment. SI was increased overall in R compared to C (9.0 ± 1.0, n=59, vs. 5.3± 0.9, n=64, SI units, P=0.0077). No significant differences in the outcome variables were found among phases. These findings confirm the effect of R on glycemic endpoints, but an influence of cycle phase was not detectable. Supported by NIH AG011915 and RR000167.