Milewicz Tomasz, Krzysiek Józef, Janczak-Saif Agnieszka, Sztefko Krystyna, Krzyczkowska-Sendrakowska Magdalena
Department of Gynecological Endocrinology Jagiellonian University, and Department of Clinical Biochemistry, Universtiy Children Hospital, Cracow, Poland.
Endokrynol Pol. 2005 Nov-Dec;56(6):883-90.
As the link between body fat and leptin is well known, the aim of the study was to seek for secondary regulators of plasma leptin level.
86 women (mean: age 47.0+/-14.3 years; estradiol 50.0+/-60.6 ng/l; FSH 52.4+/-42.9 IU/l; BMI 26.9+/-5.9) divided into three groups according to their BMI. Group A: 39 normal weight women (mean: age 44.4+/-16.0 years; estradiol 69.6+/-79.8 ng/l; FSH 50.4+/-47.7 IU/l; BMI 22.9+/-1.3). Group B: 27 overweighted women (mean: age 55.0+/-6.4 years; estradiol 25.1+/-17.2 ng/l; FSH 75.6+/-26.3 IU/l; BMI 27.7+/-1.6). Group C: 21 obese women with mean: age 48.7+/-12.2 years; estradiol 36.9+/-44.0 ng/l; FSH 42.3+/-36.6 IU/l and BMI 34.6+/-4.9.
Standard clinical evaluation and hormone evaluation (LH, FSH, prolactin, estradiol, leptin, insulin-like growth factor-I (IGF-I), human growth hormone (hGH), insulin-like growth factor binding protein-3 (IGFBP-3), insulin, dihydroepiandrosterone sulphate (DHEAS), sex hormone binding globin (SHBG) and testosterone were done in basic condition which levels of were measured by RIA kits. Statistical analysis. Shapiro-Wilk test, Mann-Whitney-Wilcoxon u test, Spearman rank correlation coefficient and stepwise multiple regression: p values of 0.05 or less were considered as significant.
Taking all women into account (n=86) the plasma leptin level correlated directly with age (r=0.32; p<0.02), body mass (r=0.60; p<0.001), BMI (r=0.71; p<0.001) as well as inversely with estradiol (r=-0.21; p<0.05), IGF-I (r=-0.24; p<0.05), SHBG (r=-0.34; p<0.01) and DHEAS (r=-0.30; p<0.01). However only in the group B leptin/age relation remained (r=0.40; p<0.05) after the division according to BMI. In the group B the leptin /DHEAS (r=-0.40; p<0.05) and leptin/PRL (r=0.51; p<0.05) links were also present. In the group C the leptin/SHGB relation (r=-0.56; p<0.02) only remained and an association between insulin and leptin was found (r=0.48; p<0.05). The body mass and BMI relation to age were again present only in all 86 women (r=0.30; p<0.002: r=0.36; p<0.001 resp.). Having split the women into groups, these links either disappeared or became inverse (rC=-0.39; p<0.05). Taking into consideration age/leptin relation in all women, the division according to the menopausal status revealed the direct relation in premenopausal women (n=29; r=0.43; p<0.02) and a reverse one in postmenopausal women (n=38; r=-0.32; p<0.05). The plasma leptin level was the highest (p<0.001) in group C (23.2+/-10.4 microg/l) and the lowest was found in the group A (8.9+/-4.1 microg/l). That corresponded with the differences in mean body mass index and mean body mass. The stepwise multiple regression revealed that body mass index accounted for 31% (p<0.001) and plasma SHBG level accounted for 17.7% (p<0.02) of plasma leptin variance in all women. In the group A body mass and age together accounted for 61% (p<0.01) and estradiol alone accounted for 44% (p<0.02) of plasma leptin variance. In the group B insulin alone accounted for 39% (p<0.05) and together with testosterone accounted for 46% (p<0.05) of plasma leptin variance. Finally in obese women none of the evaluated parameters significantly accounted for leptin variance.
The results presented in this paper confirmed the strong influence of body fat mass on serum leptin concentration. However insulin, SHBG, sex steroids as well as age may also exert secondary influence on plasma leptin level in certain groups of women.
鉴于体脂与瘦素之间的联系已广为人知，本研究旨在探寻血浆瘦素水平的二级调节因子。
86名女性（平均年龄47.0±14.3岁；雌二醇50.0±60.6 ng/l；促卵泡激素52.4±42.9 IU/l；体重指数26.9±5.9），根据体重指数分为三组。A组：39名体重正常的女性（平均年龄44.4±16.0岁；雌二醇69.6±79.8 ng/l；促卵泡激素50.4±47.7 IU/l；体重指数22.9±1.3）。B组：27名超重女性（平均年龄55.0±6.4岁；雌二醇25.1±17.2 ng/l；促卵泡激素75.6±26.3 IU/l；体重指数27.7±1.6）。C组：21名肥胖女性，平均年龄48.7±12.2岁；雌二醇36.9±44.0 ng/l；促卵泡激素42.3±36.6 IU/l，体重指数34.6±4.9。
在基础状态下进行标准临床评估和激素评估（促黄体生成素、促卵泡激素、催乳素、雌二醇、瘦素、胰岛素样生长因子-I（IGF-I）、人生长激素（hGH）、胰岛素样生长因子结合蛋白-3（IGFBP-3）、胰岛素、硫酸脱氢表雄酮（DHEAS）、性激素结合球蛋白（SHBG）和睾酮），其水平通过放射免疫分析试剂盒测定。统计分析采用夏皮罗-威尔克检验、曼-惠特尼-威尔科克森U检验、斯皮尔曼等级相关系数和逐步多元回归分析：p值小于或等于0.05被视为具有统计学意义。
将所有女性（n = 86）纳入考虑，血浆瘦素水平与年龄直接相关（r = 0.32；p < 0.02）、体重（r = 0.60；p < 0.001）、体重指数（r = 0.71；p < 0.001），与雌二醇（r = -0.21；p < 0.05）、IGF-I（r = -0.24；p < 0.05）、SHBG（r = -0.34；p < 0.01）和DHEAS（r = -0.30；p < 0.01）呈负相关。然而，根据体重指数分组后，仅在B组中瘦素与年龄的关系仍然存在（r = 0.40；p < 0.05）。在B组中，瘦素与DHEAS（r = -0.40；p < 0.05）和瘦素与催乳素（r = 0.51；p < 0.05）之间也存在联系。在C组中，仅瘦素与SHGB的关系仍然存在（r = -0.56；p < 0.02），并且发现胰岛素与瘦素之间存在关联（r = 0.48；p < 0.05）。体重和体重指数与年龄的关系仅在所有86名女性中再次出现（r = 0.30；p < 0.002；r = 0.36；p < 0.001）。将女性分组后，这些联系要么消失，要么变为相反（rC = -0.39；p < 0.05）。考虑到所有女性中年龄与瘦素的关系，根据绝经状态分组显示，绝经前女性（n = 29；r = 0.43；p < 0.02）呈正相关，绝经后女性（n = 38；r = -0.32；p < 0.05）呈负相关。血浆瘦素水平在C组中最高（p < 0.001）（23.2±10.4 μg/l），在A组中最低（8.9±4.1 μg/l）。这与平均体重指数和平均体重的差异相对应。逐步多元回归分析显示，在所有女性中，体重指数占血浆瘦素变异的31%（p < 0.001），血浆SHBG水平占17.7%（p < 0.02）。在A组中，体重和年龄共同占血浆瘦素变异的61%（p < 0.01），单独雌二醇占44%（p < 0.02）。在B组中，单独胰岛素占血浆瘦素变异的39%（p < 0.05），与睾酮共同占46%（p < 0.05）。最后，在肥胖女性中，所评估的参数均未显著解释瘦素变异。
本文呈现的结果证实了体脂量对血清瘦素浓度有强烈影响。然而，胰岛素、SHBG、性类固醇以及年龄在某些女性群体中也可能对血浆瘦素水平产生二级影响。
