THE RELATIONSHIP BETWEEN PLASMA PROGESTERONE AND PLASMA LOW- DENSITY LIPOPROTE IN CONCENTRATIONS IN HUMAN FEMALES (EXERCISE, MENSTRUAL CYCLE) by LEEDS, EILEEN M., Ph.D., Indiana University, 1984, 73 pages; AAT 8426663
Abstract (Summary)
Problem. Menstrual irregularities have been observed in women engaged in strenuous training programs. The biochemical mechanisms which explain these irregularities have never been identified. Plasma lipoprotein concentrations have been observed to change with endurance training. The cholesterol carried via the low-density lipoproteins (LDL-C) is the primary substrate for progesterone (P) synthesis in the corpus luteum. If LDL-C concentrations decrease with endurance training, then a decrease in plasma P concentration can be expected. Therefore, this study was designed to identify the relationship between LDL-C concentrations and progesterone concentrations in women at two different points in the menstrual cycle.
Methods. Forty female volunteers between 18-53 years of age were subjects. Each came to the laboratory on Day 2 and Day 23 of their menstrual cycle in a post-absorptive state. After one hour equilibration period, a 10 ml venous blood sample was taken. Plasma was analyzed for total cholesterol, high-density lipoprotein cholesterol, triglycerides, LDL-C and P. A walking maximal aerobic capacity test was performed on the same day. Data was analyzed for differences between days and correlations among variables, using paired t-tests and Pearson product- moment correlations, respectively.
Results. VO(,2) max was not different between test days. Progesterone and LDL-C had a significant negative correlation on Day 23. VO(,2) max was not significantly correlated with either variable. In addition, data from eleven women who demonstrated low luteal P were statistically compared (ANOVA) with data from a normal group (n = 29). The relationship between P and LDL-C was observed in the normal group but, not the abnormal group.
Summary. The expected relationship between P and LDL-C and aerobic fitness was not observed. However, there was a relationship observed between LDL-C and P in women who had normal luteal progesterone. Thus, VO(,2) max is not controlling progesterone concentration via alterations in LDL-C concentrations.