Background: Soy phytoestrogens are known to influence the hormonal status acting as partial estrogen agonists. Soy-derived food supplements are advised for hormone replacement therapy, prevention of atherosclerosis, age-related cognitive decline and even hormone-dependent cancer, although results from clinical studies are controversial. Whether increased soybean intake can affect the endocrine status and cognitive abilities is largely unknown. Aim: To observe the effects of 1 week of increased soybean intake on sex hormone levels and spatial cognitive abilities in women. Subjects and Methods: 16 young healthy female volunteers were asked to eat 900 g of soybeans within 1 week. Salivary testosterone (T), free and total plasma T, salivary and plasma estradiol (E) were measured by radioimmunoassay before and after the study period. Mental rotation (MR) and spatial visualization (SV) psychological tests were done at the days of sampling. Results: Soybean intake increased total plasma T levels (p < 0.02) while decreasing salivary T (p < 0.01) and not altering free plasma T levels. Salivary and plasma E levels were not changed. The results of MR and SV tests were improved after the study period. Conclusion: Short-time increased soybean intake alters the level of total plasma and salivary T and improves spatial cognition in women. Whether this effect is mediated by modulation of estrogen receptors, changes in sex hormone-binding globulin production or changes in activity of steroid-competent enzymes needs further study.
Background: Saliva reflects the plasma free fraction of testosterone which is biologically active, and available for uptake by tissues. Testosterone concentration in saliva, though differing slightly from the concentration of unbound testosterone in serum, is in good correlation with the latter, indicating that salivary testosterone provides a reliable method for determination of serum free testosterone. The study aimed to investigate salivary testosterone levels and their changes in preadolescent children and to study sexual dimorphism.
A specific radioimmunoassay for 4-androstene-3,17-dione (androstenedione) based on rabbit antisera to 6j3-hydrpxy-4-androstene-3,17-dione^6-hemisuccinate-bovine serum albumin conjugate was developed. Cross reaction by testosteröne was eliminated by additipn of experimentally established amounts of testosterone antiserum, which cross reacted by only 0.004 with androstenedione. The method has been used fpr simultaneous determination of androstenedione in both plasma and saliva of normal women under basal conditions and following dynamic tests. The plasma levels in normal women averaged 3.6 ± 0.9 nmol/1 and cprrelated (r -0.93) with those found in saliva (0.353 ± 0.089 nmol/1).
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