Androgens in general and testosterone in particular may have some protective effects on the cardiovascular system through their metabolic and direct effects upon human vasculature.

Here's a nice review of "sarcopenia," and the effects of aging on muscle fiber and type.

These data demonstrate a clear relationship between restoring serum testosterone concentrations and improvement in certain parameters of sexual function.

Testosterone gel augmentation may be helpful in hypogonadal males with depression.

Testosterone supplementation may benefit selective cognitive functions in men with Alzheimer disease and mild cognitive impairment.

This paper addresses the evidence to date regarding the safety aspects of testosterone replacement therapy.

Prostate cancer may become clinically apparent within months to a few years after the initiation of testosterone treatment. Digital rectal examination is particularly important in the detection of these cancers. Physicians prescribing testosterone supplementation and patients receiving it should be cognizant of this risk, and serum PSA testing and digital rectal examination should be performed frequently during treatment.

These data demonstrate that aromatase inhibition increases serum bioavailable and total testosterone levels to the youthful normal range in older men with mild hypogonadism. Serum estradiol levels decrease modestly but remain within the normal male range.

While short-term administration of anastrozole is an effective method of normalizing serum testosterone levels in elderly men with mild hypogonadism, it does not appear to adversely affect lipid profiles, inflammatory markers of cardiovascular risk or insulin resistance.

These results suggest that anastrozole therapy is unlikely to have an adverse effect on bone metabolism when taken over extended periods and may prove to be a valuable method of normalizing testosterone production in older men.

Epidemiological and experimental evidence strongly supports a role for estrogens in the development and growth of breast tumors. A role for estrogen in prostate neoplasia has also been postulated. Therefore, one chemopreventive strategy for breast and prostate cancers is to decrease estrogen production. This can be accomplished by inhibiting aromatase, the enzyme that catalyzes the final, rate-limiting step in estrogen biosynthesis. The use of aromatase inhibitors is of clinical interest for cancer therapy, and selective, potent aromatase inhibitors have been developed. Several of these agents have demonstrated chemopreventive efficacy in animal models. The rationale for the use of aromatase inhibitors as chemopreventives and identification of inhibitors to serve as potential chemopreventive agents are the subjects of this review. On the basis of results from preclinical studies, aromatase inhibitors may be promising agents for clinical trials in populations at high risk for developing estrogen-dependent cancers.

Arimidex increases IGF-1 levels.