Lecomte P, Lecureuil N, Lecureuil M, Lemonnier Y, Mariotte N, Valat C, Garrigue M A
Endocrinology, CHU, Tours, France.
Eur J Endocrinol. 1998 Aug;139(2):178-83. doi: 10.1530/eje.0.1390178.
Serum levels of sex-hormone-binding globulin (SHBG) have been reported in the literature to increase with age in both sexes. We have investigated the variations in levels of androgens, insulin and IGF-I with age and have evaluated their putative roles to obtain a better understanding of the increase in SHBG.
Cross-sectional pilot study of blood samples in healthy elderly subjects aged 50 to 90 years.
Forty-four postmenopausal women and 40 men were classified into three age groups. Subjects who were obese, undernourished or smokers and postmenopausal women receiving hormone replacement therapy were excluded from the study. Body mass index and waist/hip ratio were evaluated in each subject. Fasting levels of blood glucose, insulin, triglycerides, cholesterol, SHBG, testosterone, dehydroepiandrosterone sulfate (DHEAS) and IGF-I were measured. Free testosterone and glucose/insulin ratio were calculated.
The results are based on variance analysis of the mean of each parameter in the three age groups. Multiple regression analysis was performed to define the role of age, insulin and IGF-I in the increase in SHBG. The increase in SHBG with age in older men was significant but that in postmenopausal women was not. Decreasing DHEAS with age was confirmed. No significant variations in glucose and insulin were observed with age in our selected population. A positive correlation was observed between insulin and triglycerides in elderly men and women. IGF-I decreased significantly with age in both sexes. Insulin was the main factor explaining SHBG increase with age in women. In men, both age and IGF-I contributed to the SHBG increase.
The factors regulating the increase in SHBG with age appear to be different in the two sexes. Insulin plays a major role in women, whereas a decrease in IGF-I is the predominant regulating factor in men. These results should be thought of as a working hypothesis rather than a reflection of physiology.
文献报道，两性血清性激素结合球蛋白（SHBG）水平均随年龄增长而升高。我们研究了雄激素、胰岛素和胰岛素样生长因子-I（IGF-I）水平随年龄的变化，并评估了它们的假定作用，以更好地理解SHBG升高的原因。
对50至90岁健康老年受试者的血液样本进行横断面初步研究。
44名绝经后女性和40名男性被分为三个年龄组。肥胖、营养不良或吸烟的受试者以及接受激素替代疗法的绝经后女性被排除在研究之外。评估每个受试者的体重指数和腰臀比。测量空腹血糖、胰岛素、甘油三酯、胆固醇、SHBG、睾酮、硫酸脱氢表雄酮（DHEAS）和IGF-I水平。计算游离睾酮和血糖/胰岛素比值。
结果基于对三个年龄组中每个参数均值的方差分析。进行多元回归分析以确定年龄、胰岛素和IGF-I在SHBG升高中的作用。老年男性中SHBG随年龄的升高显著，但绝经后女性中不显著。证实DHEAS随年龄降低。在我们选定的人群中，未观察到血糖和胰岛素随年龄的显著变化。老年男性和女性中胰岛素与甘油三酯之间存在正相关。两性中IGF-I均随年龄显著降低。胰岛素是解释女性SHBG随年龄升高的主要因素。在男性中，年龄和IGF-I均导致SHBG升高。
调节SHBG随年龄升高的因素在两性中似乎不同。胰岛素在女性中起主要作用，而IGF-I降低是男性中的主要调节因素。这些结果应被视为一个工作假设，而非生理反映。
