Sex hormones in Malay and Chinese men in Malaysia: are there age and race differences?

The Effects of Testosterone Deficiency and Its Replacement on Inflammatory Markers in Rats: A Pilot Study

BACKGROUND

Testosterone deficiency is linked to low-grade inflammation in humans, but this condition is not replicated in an animal study. The current study aims at determining the effects of testosterone deficiency and its replacement on the circulating inflammatory cytokine level in orchidectomized male rats.

METHODS

Three-month-old Sprague-Dawley male rats (n = 18) were randomized equally into 3 groups. Bilateral orchidectomy was performed on 2 groups. The sham group was subjected to similar surgical stress, but their testes were retained. One of the orchidectomized groups received intramuscular injection of 7 mg/kg testosterone enanthate suspended in peanut oil weekly and the other 2 groups received equivolume of peanut oil injection. After 8 weeks, the rats were sacrificed and their blood was collected for the analysis of the levels of inflammatory cytokines and testosterone.

RESULTS

Testosterone level was significantly lower in the untreated orchidectomized group compared to the sham group. Testosterone replacement significantly increased the level of testosterone in the orchidectomized rats compared to the sham and untreated orchidectomized rats. Interleukin-1 alpha (IL-1α), interleukin-1 beta (IL-1β), and tumor necrosis factor alpha (TNFα) showed an increasing trend in orchidectomized rats, albeit not statistically significant. Interleukin-6 (IL-6) level increased significantly in the orchidectomized group compared to the sham group. Testosterone replacement at the supraphysiological dose did not alter the level of inflammatory cytokines significantly in orchidectomized rats.

CONCLUSIONS

Testosterone deficiency can elicit a state of low-grade inflammation, shown by an increase in interleukin-6 level, but exogenous supraphysiological testosterone replacement does not suppress the inflammation.

The Effects of Annatto Tocotrienol on Bone Biomechanical Strength and Bone Calcium Content in an Animal Model of Osteoporosis Due to Testosterone Deficiency

Osteoporosis reduces the skeletal strength and increases the risk for fracture. It is an underdiagnosed disease in men. Annatto tocotrienol has been shown to improve bone structural indices and increase expression of bone formation genes in orchidectomized rats. This study aimed to evaluate the effects of annatto tocotrienol on biomechanical strength and calcium content of the bone in orchidectomized rats. Thirty three-month-old male Sprague-Dawley rats were randomly assigned to five groups. The baseline control (BC) group was sacrificed at the onset of the study. The sham-operated group (SHAM) received olive oil (the vehicle of tocotrienol) orally daily and peanut oil (the vehicle of testosterone) intramuscularly weekly. The remaining rats were orchidectomized and treated with three different regimens, i.e., (1) daily oral olive oil plus weekly intramuscular peanut oil injection; (2) daily oral annatto tocotrienol at 60 mg/kg plus weekly intramuscular peanut oil injection; (3) daily oral olive oil plus weekly intramuscular testosterone enanthate injection at 7 mg/kg. Blood, femur and tibia of the rats were harvested at the end of the two-month treatment period for the evaluation of serum total calcium and inorganic phosphate levels, bone biomechanical strength test and bone calcium content. Annatto-tocotrienol treatment improved serum calcium level and tibial calcium content (p < 0.05) but it did not affect femoral biomechanical strength (p > 0.05). In conclusion, annatto-tocotrienol at 60 mg/kg augments bone calcium level by preventing calcium mobilization into the circulation. A longer treatment period is needed for annatto tocotrienol to exert its effects on bone strength.

A concise review of testosterone and bone health

Osteoporosis is a condition causing significant morbidity and mortality in the elderly population worldwide. Age-related testosterone deficiency is the most important factor of bone loss in elderly men. Androgen can influence bone health by binding to androgen receptors directly or to estrogen receptors (ERs) indirectly via aromatization to estrogen. This review summarized the direct and indirect effects of androgens on bone derived from in vitro, in vivo, and human studies. Cellular studies showed that androgen stimulated the proliferation of preosteoblasts and differentiation of osteoblasts. The converted estrogen suppressed osteoclast formation and resorption activity by blocking the receptor activator of nuclear factor k-B ligand pathway. In animal studies, activation of androgen and ERα, but not ERβ, was shown to be important in acquisition and maintenance of bone mass. Human epidemiological studies demonstrated a significant relationship between estrogen and testosterone in bone mineral density and fracture risk, but the relative significance between the two remained debatable. Human experimental studies showed that estrogen was needed in suppressing bone resorption, but both androgen and estrogen were indispensable for bone formation. As a conclusion, maintaining optimal level of androgen is essential in preventing osteoporosis and its complications in elderly men.

Lessons from the Bone Chapter of the Malaysian Aging Men Study

Male osteoporosis in Malaysia is a largely neglected problem. Therefore, a bone health study in men using quantitative ultrasonometry was launched as part of the Malaysian Aging Men Study in 2009–2012. This review aimed to summarize the findings of the aforementioned bone health study. The study examined the bone health of Chinese and Malaysian men aged 20 years and above living in Kuala Lumpur using a quantitative ultrasound device. Participants answered a questionnaire on their demographic details and physical activity status. Body anthropometry of the participants was measured and their blood collected for biochemical analysis. Results showed that a significant proportion of the Malaysian Chinese and Malay men had suboptimal bone health indicated by calcaneal speed of sound and vitamin D status. Age-related decline of the calcaneal speed of sound in these men was gradual and biphasic without ethnic difference. Body anthropometry such as height, weight, body mass index, and body fat percentage contributed to the variation of the calcaneal speed of sound in Malaysian men. Age-related changes in testosterone, insulin-like growth factor 1, and thyroid stimulating hormone also influenced the calcaneal speed of sound in these men. This study serves as a reminder that male osteoporosis in Malaysia should be an issue of concern. It is also a basis for a more comprehensive study on bone health in men in the future.

Vitamin D is significantly associated with total testosterone and sex hormone-binding globulin in Malaysian men

OBJECTIVE

Cross-sectional studies in the Caucasian population have shown a significant relationship between vitamin D and testosterone levels, but data in the Asian population are limited. This study aimed to determine the association between vitamin D and testosterone levels in Malaysian men.

METHODS

Chinese and Malay men (n = 382) aged 20 years or above residing in the Klang Valley, Malaysia were recruited. Their fasting blood was collected for serum testosterone, sex hormone-binding globulin (SHBG) and 25-hydroxyvitamin D (25(OH)D) assays. Relationship between 25(OH)D and testosterone levels was analyzed using multiple regression analysis. Testosterone and SHBG levels among subjects with different vitamin D status were compared using univariate analysis. Confounders such as age, ethnicity and body mass index (BMI) were adjusted.

RESULTS

25(OH)D was significantly and positively associated with total testosterone and SHBG levels before and after adjustment for age and ethnicity (p < 0.05). Only association with SHBG remained significant after further adjustment for BMI (p < 0.05). Total testosterone and SHBG values displayed an increasing trend from subjects with vitamin D deficiency to those with optimal level (p < 0.05). The trend was attenuated after adjustment for BMI (p > 0.05).

CONCLUSION

25(OH)D is significantly associated with total testosterone and SHBG in Malaysian men but this association is BMI-dependent.