Smith and colleagues (2005) undertook a prospective study on the contribution of stress to coronary heart disease. Their study, which involved 2512 men aged 45 to 59 years, looked at a number of metabolic parameters. They found that an increased cortisol to testosterone ratio was associated with a high risk of coronary artery disease and that this risk was mediated by components of the insulin resistance syndrome. They reported that high cortisol and low testosterone levels are associated with a worsening of insulin resistance and that there is evidence to support the possibility of improving this pattern by treatment with testosterone.
Opioid substances are in common use both licit and illicit. Opiates are potent analgesics but they are also highly addictive. They are frequently prescribed for both acute and chronic pain and when used chronically, often induce opiate dependence in the user. Pain clinics regularly use narcotic agents in many of their patients. Methadone, in particular, is regularly prescribed to opiate addicts who have entered a program aimed at reducing narcotic dosage and ultimately weaning the patient off it altogether. Most men who are on chronic high doses of an opiate become hypogonadal. This was first recognized in the 1970’s when heroin addicts were found to have suppressed levels of testosterone (Brambilla et al 1977). Also suppressed were LH and FSH pointing to a probable inhibition of GnRH release.
The Organon group in the Netherlands were the first to isolate the hormone, identified in a May 1935 paper "On Crystalline Male Hormone from Testicles (Testosterone)". They named the hormone testosterone, from the stems of testicle and sterol, and the suffix of ketone. The structure was worked out by Schering's Adolf Butenandt, at the Chemisches Institut of Technical University in Gdańsk.
Testosterone makes a contribution to nitric oxide formation. Nitric oxide, released from penile nerves stimulates guanylate cyclase which catalyzes the transformation of guanosine-5-triphosphate into 3′,5′-cyclic, guanosine monophosphate (cyclic GMP). Gyclic GMP causes vasodilatation and hence erection formation (Morelli et al 2005). The breakdown of cyclic GMP to GMP is mediated by the enzyme, phosphodiesterase type-5, the inhibitors of which (eg, sildenafil citrate) enhance erection formation and maintanence (Carson and Lue 2005).
If you still feel the need to supplement, keep in mind that supplemental magnesium is more likely than dietary magnesium to cause adverse effects, which is why the FDA fixed at 350 mg the Tolerable Upper Intake Level for magnesium supplementation in adults. Also, you may want to avoid magnesium oxide: it has poor bioavailability (rats absorbed only 15% in one study, and humans only 4% in another) and can cause intestinal discomfort and diarrhea.
The researchers found that the dose of testosterone required to produce different effects in the body varied widely. The influence of testosterone and estradiol also differed. As the testosterone gel dose was reduced, the scientists showed, reductions in lean mass, muscle size, and leg-press strength resulted from decreases in testosterone itself. In contrast, increases in body fat were due to the related declines in estradiol. Both testosterone and estradiol levels were associated with libido and erectile function.