Cloning and Sequence Analysis of Partial Exons of Sex Hormone Binding Globulin Gene in Pig

[Objedive] To clone the partial exons of sex hormone binding globulin （SHBG） gene in pig and provide experimental references for ac- curate separation and allocation of SHBG gene in pig. [Method] According to the sequences of SHBG gene in human and cow, one pair of primers was designed to amplify the DNA sequences of SHBG gene in pig, and the partial exons of SHBG gene were determined according to the principles of comparative genomics. Then the sequences and homology were analyzed. [ Result] The amplified SHBG gene was 841 bp in size, and its se- quences had 100.00% nucleotide homology to the CH242-411 E2 fragment on pig chromosome 12. The determined exon 4, exon 5 and exon 6 of SHBG gene were 162, 159 and 156 bp in size, respectively, and the amino acids sequences encoded by these three exons had 74.51% homology to that of human and 73.86% homology to that of cow, respectively. [ Conclusionl The partial exons of SHBG gene were determined successfully, which provides a basis for further research on the structure, accurate determination and allocation of SHBG gene in pig.

Interactions among age, adiposity, bodyweight, lifestyle factors and sex steroid hormones in healthy Singaporean Chinese men

Aim： To examine the inter-relationships among age, lifestyle factors, anthropometric parameters, percent body fat and steroid hormone parameters in 531 healthy Singaporean Chinese men aged between 29 and 72 years old. Methods： Various lifestyle parameters were quantified through a survey, and testosterone （T）, estradiol （E2）, dehydroepiandrosterone sulphate （DHEAS） and sex hormone binding globulin （SHBG） were measured using established methods. Anthropometric parameters were collected and computed, and percent body fat （Siri） was measured using the DEXA scanner. Results： SHBG, DHEAS, bioavailable-T （Bio-T）, E2, Siri, Ht, W/H, W/Ht and work stress were independently correlated with age. Using multivariate analyses and adjusting for age and other related factors, exercise, smoking and alcohol consumption have positive impacts on androgen levels and body composition. However, black and green tea consumption was associated with negative effects on body composition and with higher levels of E2 and Free Estradiol Index （FEI）. Men with shorter sleep duration had significantly lower T levels as compared to those with 6 h or more of nightly sleep. Higher T levels were associated with lower levels of adiposity and other indices of adiposity, whereas higher E2 levels were related to higher levels of adiposity. Men with higher DHEAS were significantly taller and heavier than those with low DHEAS levels. Conclusion： The study showed the close interactions among the gonadal/adrenal and metabolic compartments, with age being a key determinant in their interactions. Lifestyle factors such as exercise, smoking, sleeping and alcohol and tea consumption might play significantly roles in determining the status of health in men.

Testosterone and metabolic syndrome

Controversies surround the usefulness of identifying patients with the metabolic syndrome （MetS）. Many of the components are accepted risk factors for cardiovascular disease （CVD）. Although the MetS as defined includes many men with insulin resistance, insulin resistance is not universal. The low total testosterone （TT） and sex hormone binding globulin （SHBG） levels in these men are best explained by the hyperinsulinism and increased inflammatory cytokines that accompany obesity and increased waist circumference. It is informative that low SHBG levels predict future development of the MetS. Evidence is strong relating low TT levels to CVD in men with and without the MetS; however, the relationship may not be causal. The recommendations of the International Diabetes Federation for managing the MetS include cardiovascular risk assessment, lifestyle changes in diet, exercise, weight reduction and treatment of individual components of the MetS. Unfortunately, it is uncommon to see patients with the MetS lose and maintain a 10% weight loss. Recent reports showing testosterone treatment induced dramatic changes in weight, waist circumference, insulin sensitivity, hemoglobin Alc levels and improvements in each of the components of the MetS are intriguing. While some observational studies have reported that testosterone replacement therapy increases cardiovascular events, the Food and Drug Administration in the United States has reviewed these reports and found them to be seriously flawed. Large, randomized, placebo-controlled trials are needed to provide more definitive data regarding the efficacy and safety of this treatment in middle and older men with the MetS and low TT levels.