Exercise improves hippocampal estrogen and spatial memory of ovariectomized rats.

OBJECTIVE: The present study aimed at examining the effects of regular exercise on hippocampal estrogen and estrogen receptor ß (ERß) levels, as well as the spatial memory of ovariectomized rats. BACKGROUND: A decrease of estrogen levels leads to dysfunctions of hippocampus, including spatial learning and memory. Studies have shown that physical exercise improved spatial memory of ovariectomized rats and was associated with an increased extragonadal aromatization. This in turn affects the expression of estrogen receptors. METHODS: Ovariectomized Sprague Dawley rats were randomly assigned into the two groups, i.e. exercise and control groups. Rats of the exercise group were trained to run on a treadmill. The exercise was performed five times per week for 12 weeks. The spatial memory of rats was measured using the Morris water maze. The hippocampal estrogen and ERß  levels of rats were determined using ELISA. RESULTS: The spatial memory retention of the exercise group was significantly better than that of the control group. The hippocampal estrogen level of the exercise group was significantly higher than that of the control group. CONCLUSION: Regular exercise increases hippocampal estrogen levels and improves spatial memory retention of ovariectomized rats (Tab. 1, Fig. 4, Ref. 53).

Comparative assessment of the effects of subdermal levonorgestrel implant system and long acting progestogen injection method on lipid metabolism.

In order to compare the effects of two type of long-acting progestogen contraceptive methods with subdermal levonorgestrel (LNG) implants and depot-medroxyprogesterone acetate (DMPA) injections on lipid metabolism, a clinical cohort study was performed by requiring 25 women in each group adopting either LNG implant or DMPA injection method voluntarily. After 6 months of use, serum levels of triglycerides, total cholesterol, HDL-cholesterol and LDL-cholesterol were determined and compared between the two groups of acceptors. The mean of total cholesterol in LNG implant acceptors was significantly lower than that in DMPA injection acceptors. The mean values of HDL-cholesterol in LNG implant acceptors (41.7 +/- 7.7 mg/dl) and in DMPA injection acceptors (45.0 +/- 9.0 mg/dl) were in the normal range without significant difference between the two groups. The mean value of triglycerides did not differ significantly between LNG implant acceptors (77.6 +/- 25.1 mg/dl) and DMPA injection acceptors (91.0 +/- 30.3 mg/dl). Serum concentrations of lipid fractions such as HDL-cholesterol and LDL-cholesterol in LNG implant acceptors were relatively low compared to those in DMPA injection acceptors. Since there was a comparable reduction in both total-and HDL-cholesterol levels in the LNG implant group, the ratio of total-to HDL-cholesterol, which is thought to be a factor in determining the risk of coronary artery disease, remained in the normal range (2 +/- 4.5). This suggests that the use of these two contraceptive methods with progestogens does not alter the risk of development of coronary artery disease.

PIP: In Indonesia, researchers compared data on 25 women, 18-40 years old, using the subdermal levonorgestrel (LNG) implant (Norplant) with 25 women, 18-40 years old, using the depot-medroxyprogesterone acetate (DMPA) injectable (Depo-Provera) to evaluate the effects of these 2 long acting contraceptive methods on lipid metabolism. (Norplant releases about 30 mcg LNG/day. Each injection of Depo- Provera contains 150 mg DMPA.) Physicians followed the women for 6 months. The mean total cholesterol in the LNG group was much lower than that in the DMPA group (almost 150 vs. about 170 mg/dl; p .05). Mean values of high density lipoprotein (HDL)-cholesterol in the DMPA group and the LNG group fell within the normal range and were not significantly different (41.7 [29-62] vs. 45 [28-56] mg/dl). Even though the mean values of triglycerides and low density lipoprotein (LDL)-cholesterol were higher in the DMPA group, they were not significantly higher than those in the LNG group (91 vs. 77.6 mg/dl and 102 vs. 91.3 mg/dl, respectively). Since both total and HDL-cholesterol levels in the LNG group fell similarly, the ratio of total to HDL-cholesterol fell within the normal range for both groups (3.7 for LNG and 3.8 for DMPA). Nevertheless, both HDL and LDL were relatively lower in the LNG group, indicating that Norplant may have the more acceptable effect on lipid metabolism. Since the ratio of total to HDL-cholesterol may be a determinant of coronary artery disease, and it is within the normal range for both groups, these findings suggest that these 2 long-acting contraceptives do not affect the risk of coronary artery disease.