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Circulating Leptin Levels (circulating + leptin_level)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Circulating leptin levels and bone mineral density in children with biliary atresia

ACTA PAEDIATRICA, Issue 2 2008
Sittisak Honsawek
Abstract Aim: To investigate circulating leptin levels in biliary atresia (BA) patients and the association of leptin with bone mineral density (BMD) and the severity of BA. Methods: We have examined 50 patients with BA and 15 matched healthy controls. Serum leptin, osteocalcin and C-terminal telopeptide of type I collagen (CTX) levels were measured by sandwich enzyme-linked immunosorbent assay (ELISA). BMD of the lumbar spine was measured by dual energy X-ray absorptiometry. Results: Serum leptin levels of BA patients were lower than those of healthy controls (2.7 ± 0.3 vs. 7.1 ± 1.7 ng/mL, p = 0.0001). Among the BA patients, serum leptin levels were significantly lower in patients with jaundice than patients without jaundice (1.7 ± 0.2 vs. 3.4 ± 0.4 ng/mL, p = 0.001). BMD of BA patients was correlated (p < 0.001) with leptin levels, age and BMI (r = 0.55, r = 0.75 and r = 0.58, respectively). The serum CTX levels were significantly higher in jaundice patients compared with jaundice-free patients and the healthy controls (0.6 ± 0.2 vs. 0.2 ± 0.1 ng/mL, p = 0.01), whereas the serum osteocalcin levels in BA patients were not different from those in the controls. Conclusion: Circulating leptin levels are correlated with BMD and the presence of jaundice in BA, suggesting that the leptin may play a physiological role in maintaining bone mass of BA patients with jaundice. [source]

Hypothalamic Suppressor-of-Cytokine-Signalling 3 mRNA is Elevated and Pro-Opiomelanocortin mRNA is Reduced During Pregnancy in Brandt's Voles (Lasiopodomys brandtii,)

JOURNAL OF NEUROENDOCRINOLOGY, Issue 9 2008
G.-B. Tang
Leptin acts within the hypothalamus to diminish food intake. In Brandt's voles (Lasiopodomys brandtii), both circulating leptin levels and food intake are elevated during pregnancy, suggesting an ineffectiveness of leptin to reduce food intake. Diminished hypothalamic leptin receptors and impaired leptin signal transduction are characteristic of central leptin resistance. The present study aimed to determine whether these characteristic modulations of leptin sensitivity occurred in pregnant Brandt's voles. The mRNA expression of the long form of the leptin receptor (Ob-Rb), suppressor-of-cytokine-signalling 3 (SOCS3), neuropeptide Y (NPY), agouti-related protein (AgRP), pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) in the hypothalamus were examined on dioestrous, day 5, day 10 and day 18 of pregnancy. Compared to controls, there was no significant change in hypothalamic Ob-Rb mRNA during the pregnancy. SOCS3 mRNA was increased significantly by 68% on day 10% and 93% on day 18 of pregnancy compared to controls. Despite elevated leptin levels, POMC mRNA was decreased significantly by 60% on day 18 of pregnancy, whereas no differences were found in the mRNA expression of NPY, AgRP and CART in pregnant voles compared to controls. The elevation of SOCS3 mRNA together with disrupted leptin regulation of neuropeptides in the hypothalamus suggests that leptin resistance may develop in pregnant Brandt's voles. [source]

Reduced lipolysis and increased lipogenesis in adipose tissue from pinealectomized rats adapted to training

JOURNAL OF PINEAL RESEARCH, Issue 2 2005
Cristina N. Borges-Silva
Abstract:, The current study investigated the effects of chronic training and pinealectomy on the lipogenic and lipolytic activity of adipose tissue. Pinealectomized and sham-operated adult male Wistar rats were distributed in to four subgroups: pinealectomized untrained, pinealectomized trained, control untrained and control trained. At the end of the training period (8 wk) the rats were killed. Blood samples were collected for glucose, insulin and leptin determinations. Peri-epididymal adipocytes were isolated for measurement of in vitro rates of lipolysis and incorporation of substrates (d -[U- 14C]-glucose, l -[U- 14C]-lactate, [2- 14C]-acetate and [1- 14C]-palmitate) into lipids, and samples of epididymal adipose tissue were homogenized for evaluation of glucose-6-phosphate dehydrogenase maximal activity. Pinealectomy resulted in a significantly increased lipolytic capacity in response to isoproterenol and a decrease in circulating leptin levels without affecting the rates of incorporation of different substrates into lipids. However, only in the intact control group did training promote a higher basal and isoproterenol-stimulated lipolysis, increase the incorporation of palmitate (esterification), decrease the incorporation of acetate (lipogenesis) into lipids and diminish circulating leptin levels. These effects of exercise training were not seen in pinealectomized rats. However, pinealectomized trained animals showed a marked reduction in lipolysis and an increased rate of acetate incorporation. In conclusion, we demonstrated for the first time that the pineal gland plays an important role in the regulation of lipid metabolism in such a way that its absence caused a severe alteration in the balance between lipogenesis and lipolysis, which becomes evident with the adaptation to exercise training. [source]