ABSTRACT
BACKGROUND: Leptin is known to affect bone metabolism both centrally and peripherally. This study was performed to investigate the relationship between leptin and bone mineral density(BMD) in healthy premenopausal and postmenopausal Korean women. METHODS: 140 women were recruited for a routine health check-up. Anthro-pometric and biochemical data were checked as usual. BMDs were measured by dual x-ray absorptiometry of the spine and femur in 67 premenopausal women and 73 postmenopausal women, in addition to their serum leptin levels. RESULTS: Serum leptin level showed no correlation with BMD in premenopausal women, but there was a positive correlation betwen serum leptin and spinal BMD in postmenopausal women(r=0.468, p<0.001). After the correcting for age, body mass index, and duration of menopause, the serum leptin level and BMD still showed a positive correlation(r=0.217, p=0.088) although weak. The women in the lowest quartile of serum leptin level showed significantly lower lumbar and femoral neck BMD. CONCLUSION: Leptin level seems to have a weak relationship with BMD showing different features in premenopausal and postmenopausal women.
Subject(s)
Female , Humans , Absorptiometry, Photon , Body Mass Index , Bone Density , Femur , Femur Neck , Leptin , Menopause , Metabolism , SpineABSTRACT
The ob gene product leptin is thought to be an adipostatic hormone through the regulation of food intake and energy expenditure. There are many reports that serum leptin concentration was increased in CRF patients, especially CAPD patients. The causes of elevated serum leptin concentration in CRF are believed to be multifactorial. Increased body fat mass, decreased residual renal function, active inflammation and hyperinsulinemia all are suggested to influence serum leptin concentration in CAPD patients. In this study, in order to investigate the pathogenic mechanism of increased serum leptin level in CAPD patients, we observed the changes of serum leptin concentration, leptin expression in the abdominal subcutaneous fat tissue, body fat composition, residual renal function, serum insulin concentration and CRP. Thirteen patients(7 men and 6 women, mean age 53+/-14 years) were enrolled in this study. Serum leptin concentration was measured by RIA before start of CAPD(baseline data), 5 days and 1, 3 months after start of CAPD. Simultaneously, fat tissues were aspirated from the abdominal subcutaneous fat tissues for analysis of ob gene expression. Ob mRNA expression was measured by semiquantitative RT-PCR method. The changes of serum insulin concentration, C-reactive protein, residual renal function were measured. All studies were done immediately before starting CAPD, 5 days, 1 month and 3 months after starting CAPD. Total body fat was estimated by dual energy X-ray absorptiometry and abdominal visceral and parietal fat area measured by computed tomography were done at 1-3 days(baseline data), 1 month, 3 months after start of CAPD. Serum leptin concentration increased significantly as early as 5 days after start of CAPD and maintained high up to 3 months(4.3+/-2.6->8.2+/-7.6->7.4+/-6.5->10.8+/-13.8ng/mL), while leptin expression in the abdominal subcutaneous fat tissue did not change during the study period(0.24+/-0.06->0.25+/-0.08->0.20+/-0.07->0.34+/-0.21ng/mL). No significant changes of body fat composition, residual renal function and serum insulin concentration were observed during the study period. These results suggest that increase of serum leptin concentration after CAPD may be due to increase of local leptin production, especially from the peritoneum, as has also been suggested by several reports of relatively higher dialysate leptin.
Subject(s)
Female , Humans , Male , Absorptiometry, Photon , Adipose Tissue , C-Reactive Protein , Eating , Energy Metabolism , Gene Expression , Hyperinsulinism , Inflammation , Insulin , Leptin , Peritoneal Dialysis, Continuous Ambulatory , Peritoneum , Prospective Studies , Rabeprazole , RNA, Messenger , Subcutaneous Fat, AbdominalABSTRACT
PURPOSE: Leptin is a highly hydrophilic 16-kDa protein which is produced in the adipose tissue and participates in the regulation of food intake and energy expenditure. The aim of the present study was to examine the relation between umbilical cord blood leptin concentration and intrauterine growth. METHODS: Ninety-seven full-term newborn infants who were born in Yeungnam University Hospital from July to August 1998 were included in the study. They were divided into 3 groups related to birth weight : appropriate for gestational age(AGA) group(n=73), large for gestational age(LGA) group(n=17), small for gestational age(SGA) group(n=7). Birth weight, head circumference, mid-arm circumference, mid-arm circumference to head circumference ratio, Ponderal index, and BMI were measured at birth. Maternal body weight and placental weight were measured. Leptin concentrations of cord blood and maternal serum were measured by a RIA method, and testosterone, estradiol, insulin, c-peptide, glucose, white blood cell, hemoglobin, platelet count of cord blood were also measured. RESULTS: Leptin concentration in cord blood was positively correlated to birth weight and body length. Leptin concentrations(microgram/L) in cord blood were significantly different among groups(10.1+/-1.1 in LGA group, 8.7+/-0.9 in AGA group, 1.7+/-0.1 in SGA group). There was a statistically significant difference in leptin concentration of cord blood between female and male infants(11.6+/-1.9, versus 6.7+/-0.9). There was no significant correlations between leptin concentration of cord blood and placental weights or maternal leptin concentration. Therefore leptin concentration of cord blood can not inflect maternal leptin concentration but intrauterine fetal growth. CONCLUSION: Leptin in cord blood might originate mainly from fetal adipose tissue rather than the placenta, and may be related to fetal growth.