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Could testosterone supplements help prevent Alzheimer´s disease? It is possible, according to results of a new study in which researchers exposed nerve cells to the male hormone. In the presence of testosterone, nerve cells collected from rats and mice tended to produce a harmless or beneficial form of beta-amyloid protein rather than the form that makes up plaques in the brains of Alzheimer´s disease patients. "The testosterone directs the metabolism so that much more goes to the good pathway and much less to the bad pathway, "study co-author Dr. Paul Grengard said in an interview with Reuters Health. "In other words, you get much less beta-amyloid peptide and you get more of this secretory beta-amyloid precursor protein, which is considered by most people to be beneficial for the health of the nerve cells, "he added. Greengard, of The Rockefeller University in New York, and colleagues published their findings in the February 1st issue of Proceedings of the National Academy of Sciences of the United Stares of America, Vol 97, Issue 3, 1202-1205, February 2000.
Gouras GK, Xu H, Gross RS, Greenfield JP, Hai B, Wang R, Greengard P.
To determine the effect of oral administration of a purified lipidic extract from Lepidium meyenii (MacaPure M-01 and M-02) on the number of complete intromissions and mating in normal mice, and on the latent period of erection (LPE) in rats with erectile dysfunction, mice and rats were randomly divided into several experimental and control groups. A 10% ethanol suspension of M-01 and M-02 was orally administered for 22 days to the experimental groups according to the dosage specified by the experimental design. Oral administration of M-01 and M-02 enhanced the sexual function of the mice and rats, as evidenced by an increase in the number of complete intromissions and the number of sperm-positive females in normal mice, and a decrease in the LPE in male rats with erectile dysfunction. The present study reveals for the first time an aphrodisiac activity of L. meyenii, an Andean Mountain herb.
Zheng BL, He K, Kim CH, Rogers L, Shao Y, Huang ZY, Lu Y, Yan SJ, Qien LC, Zheng QY.
SEX HORMONE LEVELS AND SEXUAL ACTIVITY OBJECTIVES: To assess the changes in sex hormone levels with age and the relationship of sexual functioning to testosterone levels, evaluating serum testosterone levels and erectile function in men with lower urinary tract symptoms (LUTS). PATIENTS AND METHODS: The study included 213 men with LUTS (age range 31-78 years) who had no confirmed erectile dysfunction. Their serum total and free testosterone, and sex-hormone binding globulin (SHBG) levels were measured, and they completed the International Index of Erectile Function (IIEF) questionnaire. RESULTS: The total and free testosterone levels decreased and SHBG increased with age, but only the change in free testosterone and SHBG were statistically significant. The correlation with age was closer for free testosterone (r = - 0.356, P < 0.001) than for SHBG (r = 0.177, P = 0.010). Regression analysis of the five domain scores of the IIEF and three hormonal levels, after correcting for age, showed that free testosterone level was significantly correlated with erectile function (r = 0.2136, P = 0.005) and orgasmic function (r = 0.179, P = 0.020), but SHBG levels were significantly correlated only with orgasmic function (r = - 0.154, P = 0.046). Total testosterone levels showed no significant correlation with any of the five domains of the IIEF. CONCLUSIONS: Of the sex hormone levels, the change in free testosterone correlated most closely with ageing and had the closest correlation with sexual activity. Contrary to previous reports, free testosterone and SHBG levels were significantly correlated with orgasmic function and/or erectile function rather than sexual desire. A complete study of sex hormone levels is needed to evaluate patients with erectile dysfunction.
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