Testosterone

Testosterone

• Testosterone is an anabolic/androgenic hormone.
• Naturally produced in both men and women.
  • Men: Testis and Adrenal Cortex
  • Women: Adrenal Cortex
  • Men normally have 10 times the resting serum testosterone concentration of women (Kraemer et al. 1991)
• Function
  • Increased body growth
  • Increased deposition of bone salts
  • Adult levels stimulate epiphyseal plate closure
  • Postnatal increases contributes to larger fibers from induction of muscle protein accretion
• SHBG Protein Binding
  • More binding
    • less free testosterone
• Bioavailable Testosterone
  • Increased by diets high in fat and protein
  • Decreased in vegan diets (as is IGF-I)
  • Decreased in diets high in carbs
  • Decreased if soy protein is substituted for meat protein
    • Habito RC, Montalto J, Leslie E, Ball MJ (2000). Effects of replacing meat with soyabean in the diet on sex hormone concentrations in healthy adult males. Br J Nutr. 84(4):557-63.
  • Percentage free is 1.6 to 2.9 percent

Testosterone Production

• Pituitary
  • secretes Luteinizing Hormone (LH)
  • affects Testes
• Cholesterol
  • -> Pregnenolone
    • -> Progesterone
      • -> Aldosterone (mineral balance)
      • -> Cortisol (stress)
      • -> Androstenedione
        • See Androstenedione's conversion below
    • -> DHEA
      • -> Androstenedione
        • -> Estrone
        • <-> Testosterone
          • Free (active)
            • decreases with SHBG (see below)
          • Bound (inactive)
            • Sex Hormone Binding Globulin (SHBG)
              • Increases with age
              • Increases with high estrogen
                • brought about by blood sugar imbalance
          • -> Dihydrotestoterone (DHT)
          • -> Estradiol
            • About one percent of testosterone is converted to estrogen

Defects Resulting in Low Testosterone Symptoms

• Elevated Stress
  • increases Cortisol
    • suppresses Pituitary function
      • decreases Luteinizing Hormone (LH)
        • decreases testosterone production
    • 'Pregnenolone Steal' during chronic stress
      • body favors Cortisol production
        • over sex hormone production
        • for survival
    • increased blood sugar (see below)
• Blood Sugar Imbalances
  • increases Progesterone -> Androstenedione -> Estrone
    • Androstenedione is weak androgen
      • 5 times weaker than testosterone
      • competes with testosterone for binding on androgen receptors
    • Higher Estrone to testosterone balance
      • causes further insulin secretions in body
      • normal testosterone
    • Estrogen increases SHBG
      • decreases free testosterone
• Impaired Liver Detoxification
  • impedes estrogen's breakdown
    • half life of testosterone: 7 minutes
    • half life of estrogen: hours
    • increases estrogen : testosterone ratio
• Increased Dihydrotestoterone (DHT) production
  • 5-delta Desaturase converts testosterone to DHT
  • DHT has 10 times stronger infinity to receptor as compared to testosterone
    • leads to receptor resistance to testosterone
• Dietary Deficiencies
  • Zinc
    • Low Zinc decreases testosterone production
    • Low stomach acid decreases absorption of zinc

Diagnostics

• Get tested if you have symptoms of low testosterone
• Many defects possible, creating low testosterone symptoms
  • many may not require hormone replacement
  • normal testosterone but low testosterone symptoms
• Testosterone
• Male hormone panel includes
  • total and free testosterone
  • estrogens (estrione, estradiol, estriol)
  • androstenedione
  • sex hormone binding globulin
  • DHEA
  • DHT
  • Luteinizing hormone.
  • Cortisol
    • Adrenal salivary panel
  • Salivary testing can be used for male hormones

See more information on BPA and other Hormone Disruptors.