Resistance of sperm motility to serum testosterone in men with excessive erythrocytosis at high altitude.

Excessive erythrocytosis (EE) [hemoglobin (Hb) >21 g/dl] observed in natives at high altitude (HA) seems to be due to elevated serum testosterone levels compared with men without EE at HA. The aim of the study was to determine the association between serum testosterone levels and high hemoglobin levels at HA with sperm quality. The study was conducted with 72 adult men living at 4,340 m and 52 native men at sea level (SL). At HA, men were grouped according to hemoglobin value (group 1:16-21 g/dl or group 2: Hb >21 g/dl). Hemoglobin and serum testosterone levels were evaluated. Sperm concentration, percentage of progressive sperm motility, percentage of normal sperm morphology, and markers of seminal vesicles function (corrected seminal fructose) and of prostate function (seminal zinc levels) were calculated. Serum testosterone levels were significantly higher in the group with EE (p<0.001). Progressive sperm motility in men with EE was lower than in the other group (Hb >16-21 g/dl) and that of those at SL. Seminal pH, zinc levels and normal sperm morphology in men at HA were lower than at SL. At HA, a significant inverse relationship was observed between hemoglobin and progressive sperm motility (p<0.01). At SL, serum testosterone levels were directly related with progressive sperm motility, whereas at HA, no association was observed (p>0.05). No association between testosterone levels and corrected seminal fructose was observed in men with EE. In conclusion, low sperm motility was observed in men with EE despite elevated serum testosterone levels suggesting a resistance of sperm motility.

Aromatase activity after a short-course of letrozole administration in adult men at sea level and at high altitude (with or without excessive erythrocytosis).

Men living at high altitudes in Peru compared to sea level counterparts have erythrocytosis (hemoglobin 16-21 g/dl) or excessive erythrocytosis (hemoglobin>21 g/dl). High testosterone (T) levels in men at high altitude (HA) were associated with excessive erythrocytosis. High androgen levels could be due to a low aromatase activity or to an elevated rate of conversion from precursors to testosterone. The aim of this study was to evaluate aromatase activity and rate of conversion from precursors to testosterone before and after administration of the aromatase enzyme inhibitor letrozole (5 mg/day) for a 5-day period to men at HA and at sea level (SL). The response to short term aromatase inhibition was assessed in 30 adult men living at sea level, 31 native men at HA with erythrocytosis (Hb 16-21 g/dl), and 35 men at HA with excessive erythrocytosis (Hb>21 g/dl). Serum hormone levels, estradiol/testosterone, testosterone/androstenedione, and testosterone/dehydroepiandrosterone sulfate (DHEAS) ratios were measured. Men with erythrocytosis had lower basal serum T/androstenedione ratios than men with excessive erythrocytosis at HA and men at sea level. Men at HA with excessive erythrocytosis had higher T/DHEAS ratios than men with erythrocytosis and than those at sea level before and after letrozole administration. After letrozole administration, both groups of men at high altitude (with erythrocytosis or with excessive erythrocytosis) showed lower aromatase activities than those at sea level. In conclusion, higher serum testosterone levels in men with excessive erythrocytosis were associated with an increased rate of conversion from DHEAS to testosterone rather than to a lower aromatase activity.

Serum testosterone levels and score of chronic mountain sickness in Peruvian men natives at 4340 m.

Life at high altitudes (>4000 m) is associated with higher erythropoiesis. Haemoglobin ≥21 g dl(-1) is considered as excessive erythrocytosis and is a sign of chronic mountain sickness (CMS). The present study was designed to determine an association between serum testosterone (T) and serum oestradiol (E(2) ) levels with the score of CMS. One hundred and seventeen men natives from low altitude (150 m) and 103 men natives from high altitude (4340 m) were studied. The presence of breathlessness or palpitations, sleep disturbance, cyanosis, dilatation of veins, paraesthesia, headaches, tinnitus and Hb ≥21 g dl(-1) , have been included for the CMS score. Men living at high altitude had higher CMS score (P < 0.001), serum T (P < 0.05) and serum E(2) levels (P < 0.04) and had lower serum luteinising hormone levels (P < 0.005) than men living at sea level. At high altitude, the group with the highest CMS score (≥10) showed higher chronological age, SpO(2) , serum T and ratio T/E(2) than the group with CMS score of ≤4. Some symptoms of CMS as sleep disorders and paraesthesia were more related to high serum T level; cyanosis was more related to higher haemoglobin values. In conclusion, higher serum T levels were associated to higher scores of CMS.

Antagonistic effect of Lepidium meyenii (red maca) on prostatic hyperplasia in adult mice.

The plants from the Lepidium gender have demonstrated to have effect on the size of the prostate. Lepidium meyenii (Maca) is a Peruvian plant that grows exclusively over 4000 m above sea level. The present study was designed to determine the effect of red maca (RM) in the prostate hyperplasia induced with testosterone enanthate (TE) in adult mice. Prostate hyperplasia was induced by administering TE, and then these animals (n = 6, each group) were treated with RM or Finasteride (positive control) for 21 days. There was an additional group without prostate hyperplasia (vehicle). Mice were killed on days 7, 14 and 21 after treatment with RM. Testosterone and oestradiol levels were measured on the last day of treatment. Prostatic stroma, epithelium and acini were measured histologically. RM reduced prostate weight at 21 days of treatment. Weights of seminal vesicles, testis and epididymis were not affected by RM treatment. The reduction in prostate size by RM was 1.59 times. Histological analysis showed that TE increased 2-fold the acinar area, effect prevented in the groups receiving TE + RM for 14 (P < 0.05) and 21 (P < 0.05) days and the group receiving TE + Finasteride for 21 days (P < 0.05). TE increased prostatic stroma area and this effect was prevented by treatment with RM since 7 days of treatment or Finasteride. The reduction in prostatic stroma area by RM was 1.42 times. RM has an anti-hyperplastic effect on the prostate of adult mice when hyperplasia was induced with TE acting first at prostatic stromal level.