Dundar Bumin, Dundar Nihal, Erci Tayfun, Bober Ece, Büyükgebiz Atilla
Department of Pediatric Endocrinology, Faculty of Medicine, Süleyman Demirel University, Turkey.
J Pediatr Endocrinol Metab. 2005 Oct;18(10):929-34. doi: 10.1515/jpem.2005.18.10.929.
It has been reported that there is a relationship between circulating leptin and sex steroid hormones and leptin is able to stimulate estrogen secretion by increasing aromatase activity in adipose stromal cells and breast tissue. Leptin receptors have been also shown in mammary epithelial cells and it has been suggested that leptin is involved in the control of the proliferation of both normal and malignant breast cells.
To investigate circulating leptin levels in boys with pubertal gynecomastia.
Twenty boys with pubertal gynecomastia who were in early puberty and had no obesity, and 20 healthy individuals matched for age, pubertal stage and body mass index (BMI) with the study group, were enrolled in the study. Body weight, height and left midarm circumference (MAC) and left arm triceps skinfold thickness (TSF) were measured and BMI was calculated. A fasting blood sample was collected and routine hormonal parameters including prolactin, beta-human chorionic gonadotropin (betaHCG), total and free testosterone, estradiol, luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin, androstenedione (AS) and dehydroepiandrosterone sulfate (DHEAS) levels were studied. Serum leptin levels were analyzed using radioimmunoassay.
The mean ages of the study and control group were not different (13.9 +/- 0.89 and 14.2 +/- 0.66, respectively). No significant difference was found for BMI, MAC and TSF values between the two groups. There was no significant difference for hormonal parameters including FSH, LH, total and free testosterone, estradiol, AS, DHEAS and estradiol/total testosterone ratio between boys with pubertal gynecomastia and the controls. Serum leptin levels were found significantly higher in the study group compared with the healthy controls (5.58 +/- 0.81 and 2.39 +/- 0.29 ng/ml, respectively; p <0.001). No correlation could be determined between serum leptin levels and hormonal parameters.
The presence of higher leptin levels in boys with pubertal gynecomastia indicates that leptin may be involved in the pathogenesis of pubertal gynecomastia. The role of circulating leptin in pubertal gynecomastia is probably related to increase in estrogen and/or estrogen/ androgen ratio by the stimulating effect of leptin on aromatase enzyme activity in both adipose and breast tissues, or a direct growth stimulating effect of leptin on mammary epithelial cells, or increase in sensitivity of breast epithelial cells to estrogen with inducing functional activation of estrogen receptors by leptin in breast tissue.
据报道，循环中的瘦素与性类固醇激素之间存在关联，并且瘦素能够通过增加脂肪基质细胞和乳腺组织中的芳香化酶活性来刺激雌激素分泌。乳腺上皮细胞中也已发现瘦素受体，有人提出瘦素参与正常和恶性乳腺细胞增殖的控制。
研究青春期男性乳腺增生男孩的循环瘦素水平。
选取20名青春期早期、无肥胖的青春期男性乳腺增生男孩，以及20名年龄、青春期阶段和体重指数（BMI）与研究组相匹配的健康个体作为研究对象。测量体重、身高、左中臂围（MAC）和左肱三头肌皮褶厚度（TSF），并计算BMI。采集空腹血样，研究包括催乳素、β-人绒毛膜促性腺激素（βHCG）、总睾酮和游离睾酮、雌二醇、黄体生成素（LH）、卵泡刺激素（FSH）、催乳素、雄烯二酮（AS）和硫酸脱氢表雄酮（DHEAS）水平在内的常规激素参数。采用放射免疫分析法分析血清瘦素水平。
研究组和对照组的平均年龄无差异（分别为13.9±0.89岁和14.2±0.66岁）。两组间BMI、MAC和TSF值无显著差异。青春期男性乳腺增生男孩与对照组之间，包括FSH、LH、总睾酮和游离睾酮、雌二醇、AS、DHEAS以及雌二醇/总睾酮比值在内的激素参数无显著差异。与健康对照组相比，研究组的血清瘦素水平显著更高（分别为5.58±0.81和2.39±0.29 ng/ml；p<0.001）。血清瘦素水平与激素参数之间未发现相关性。
青春期男性乳腺增生男孩中存在较高的瘦素水平，这表明瘦素可能参与青春期男性乳腺增生的发病机制。循环瘦素在青春期男性乳腺增生中的作用可能与瘦素对脂肪和乳腺组织中芳香化酶活性的刺激作用导致雌激素和/或雌激素/雄激素比值增加有关，或者与瘦素对乳腺上皮细胞的直接生长刺激作用有关，或者与瘦素诱导乳腺组织中雌激素受体功能激活从而增加乳腺上皮细胞对雌激素的敏感性有关。
