Biomedical subjects

Ginger R Kraemer

Publications and source records attributed to Ginger R Kraemer.

4 recordsLinked to original sources

PubMed2006

Interrelationships of serum estradiol, estrone, and estrone sulfate, adiposity, biochemical bone markers, and leptin in post-menopausal women.

OBJECTIVE: The aim of this study was to examine the relationships between endogenous estrogens and adiposity, bone markers, and leptin in post-menopausal (PM) women. DESIGN: Seventy-three post-menopausal (PM) women participated in a clinical correlational study. Weight, height, waist-hip ratio, fasted morning serum and first morning voided urine samples were obtained to compare body mass index (BMI), waist-hip ratio, endogenous estrogens, leptin, and bone markers. Serum estradiol, estrone (E1), estrone sulfate (E1S), leptin, osteocalcin, and urinary deoxypyridinoline (Dpd) were determined. RESULTS: Significant positive relationships were found between BMI and estradiol, E1, and E1S (r = 0.52, 0.38, and 0.29; P < or = 0.001, 0.001, and 0.013 respectively). Significant relationships between leptin and estrogens were revealed, but were not significant when BMI was used as a covariate. Although many subjects revealed elevated bone marker levels, no correlation between estrogens or BMI and bone markers (Dpd and osteocalcin) was found. CONCLUSIONS: There are significant positive correlations between estrogens and BMI in PM women. Increasing levels of estradiol, E1, and E1S with increasing BMI may be an indicator of adiposity, but are without effect as a stimulatory factor on leptin production. Waist-hip ratio did not significantly affect leptin concentrations when accounting for BMI. Due to assay sensitivity in the present study, data represent a more precise representation of these relationships. The lack of correlation between estrogens and bone marker levels may have been due to low estrogen levels in PM women.

Adipose Tissue↗

PubMed2003

Variability of serum estrogens among postmenopausal women treated with the same transdermal estrogen therapy and the effect on androgens and sex hormone binding globulin.

OBJECTIVE: To examine the variability of serum estrogens in response to transdermal estrogen replacement therapy (ET), and to determine the effects on androgens and sex hormone binding globulin (SHBG). DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Women's hospital. PATIENT(S): Two groups of postmenopausal women: [1] 21 women not on ET enrolled and 17 completed the study; [2] 19 women on continuous transdermal ET enrolled and 13 completed the study. INTERVENTION(S): Women not on ET were administered a placebo patch or a newly initiated estrogen patch, then crossed over to the alternate treatment. Serum samples were obtained at baseline and the subsequent 3 days from the placebo and new-patch groups and from a separate group of women receiving continuous estrogen patch treatment. MAIN OUTCOME MEASURE(S): Estradiol (E(2)), estrone, estrone sulfate, T, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), androstenedione, free androgen index, and SHBG. RESULT(S): There was considerable intrapatient and interpatient variability in the estrogen response to identical treatment doses, with E(2) values differing between women as much as 138 pg/mL and E(2) increases above baseline differing as much as 90 pg/mL. Continuous treatment increased SHBG and decreased androstenedione levels; however, levels of T, DHEA, DHEAS, and free androgen index did not change. CONCLUSION(S): There is great variability of estrogen in response to transdermal ET, but minimal effect on circulating androgens.

Administration, Cutaneous↗

PubMed2003

Effects of high-intensity exercise on leptin and testosterone concentrations in well-trained males.

OBJECTIVE: A number of investigations have examined the effect of exercise on leptin concentrations, because leptin is associated with obesity, satiety, and reproductive function. High-intensity exercise is known to increase testosterone, an inhibitor of leptin. The objective of the study was to determine whether the leptin responses to a progressive, intermittent exercise protocol were related to serum testosterone concentrations. Most previous studies have examined leptin responses to low or moderately high exercise intensities. A second objective was to determine whether leptin responses were different than previous experiments using intermittent moderate and high-intensity exercise. METHODS: Well-trained runners completed strenuous intermittent exercise consisting of treadmill running at 60, 75, 90, and 100% VO(2 max) and a subsequent resting control trial was also conducted. RESULTS: There were significant increases in mean serum levels of leptin and testosterone with both quickly returning to baseline during recovery, but no relationship between the two hormones was found. After examining individual data for both hormones, it was discovered that subjects could be classified as leptin responders or nonresponders, whereas testosterone increased in all subjects. Responders had elevated serum leptin levels at baseline and exhibited increases after high-intensity exercise, whereas nonresponders did not show changes in leptin during exercise. CONCLUSIONS: Data suggest testosterone levels do not acutely affect leptin responses to exercise or 1-h of recovery. Moreover, varied leptin responses to intense exercise in comparable well-trained runners was observed and was associated with baseline leptin concentrations.

Adult↗

PubMed2002

Substrate utilization during exercise in postmenopausal women on hormone replacement therapy.

It has been suggested that due to the slight direct or indirect effect of estrogen on lipolytic activity, the age-related decrease in production associated with the menopause may heighten the risk of cardiovascular and metabolic disease in women. While hormone replacement therapy (HRT) alone may have little or no effect on body mass in postmenopausal women, data suggest it can alter the shift toward abdominal adiposity. Furthermore, estrogen may have a synergistic effect on exercise-induced reduction in fat mass. Accordingly, the purpose of this investigation was to examine the potential influence of HRT on substrate utilization during 30 min of treadmill exercise at approximately 80% maximal oxygen uptake (VO(2max)) in postmenopausal women. Eight women were receiving HRT and nine women were not (NHRT). No significant differences between the HRT and NHRT groups were noted for age, body mass, body fat, VO(2max) or the percentage of VO(2max) maintained during exercise. Expired gas samples were analyzed every 30 s to determine respiratory exchange ratio (R) and % VO(2max). The R, total energy expended and percentage contributions from fats and carbohydrate were averaged over three periods during the exercise (min 1-10, 11-20, and 21-30). There was no effect of HRT on R, total energy expended or substrate contribution. Thus, treatment of postmenopausal women using HRT (primarily conjugated equine estrogens in doses of 0.625-1.25 mg x day(-1)) did not appear to affect the percentages of fat and carbohydrate utilized during 30 min of treadmill exercise at 80% of VO(2max). However, the exercise responses in this group of menopausal women were consistent with a duration-dependent increased reliance on fat as an energy source during exercise of moderate to vigorous intensity as has been demonstrated in younger populations.

Aged↗