Disease relevance of LEP

• Among those with the LEP 19G allele, an increased risk estimate was found for all NHL [OR = 1.6, confidence interval (CI) 1.1-2.3], DLCL (OR = 1.6, CI 0.86-3.0), and FL lymphoma (OR = 1.9, CI 0.98-3.6) [1].
• Findings varied with leptin genotype, the risks being decreased with LEP 19AA (OR = 0.7, 95% CI 0.5-1.0) and increased with LEP -2548GA (OR = 1.3, 95% CI 1.0-1.7) and -2548AA (OR = 1.4, 95% CI 1.0-1.9), particularly for follicular lymphoma [2].
• The present study is to investigate whether chromosomal regions 7q and 11q, which contain LEP and UCP2/UCP3, respectively, can be excluded for linkage with obesity phenotypes [3].
• A modest elevated spina bifida risk, irrespective of maternal BMI, was observed for two LEP microsatellite alleles (257 and 271) [4].
• CONCLUSION: Our results indicated that the polymorphisms in LEP and LEPR genes are associated with increased breast cancer risk as well as disease progress, supporting our hypothesis for leptin involvement in cancer pathogenesis [5].
• Hyperleptinemia and high FF leptin are important pathologies of PCOS with infertility [6].
• Following weight loss there were leptin-reversible increases in neural activity in response to visual food cues in the brainstem, culmen, parahippocampal gyrus, inferior and middle frontal gyri, middle temporal gyrus, and lingual gyrus [7].

Psychiatry related information on LEP

• The inverse association between the Q223R polymorphism and obesity (OR = 0.62; 95% CI: 0.39-0.99) remained significant even after additional adjustment for education, tobacco smoking, alcohol, physical activity, origin of the obese patient, and the -2548G > A polymorphism in the LEP gene (OR = 0.54; 95% CI: 0.32-0.89) [8].
• The circadian rhythm of several plasma hormones (prolactin, growth hormone, adrenocorticotropic hormone (ACTH), cortisol, and melatonin) was simultaneously evaluated in 23 women with anorexia nervosa (AN), in 27 obese (OB) women, and in gender and age-matched healthy controls [9].
• Finally, we discuss the possibility that leptin, the OB gene product, may be the link of some of these endocrine abnormalities, and that its abnormal secretion during stroke may contribute to the eating disorders and poor nutritional status often seen in these patients [10].
• Reaction time, subjective pain intensities and evoked vertex potentials to laser (LEP) and electrical (SEP) stimuli were recorded and compared with auditory evoked potentials (AEP) [11].
• The MMPI profiles of the obese subjects were compared to those of a general medical population of 50,000 patients seen in the Department of Internal Medicine at the Mayo Clinic. Obese male subjects had significantly higher scores on the F and MA scales [12].

High impact information on LEP

• BACKGROUND: Obese women with the polycystic ovary syndrome are relatively unresponsive to the induction of ovulation by clomiphene [13].
• CONCLUSIONS: Obese patients who took fenfluramine and phentermine, dexfenfluramine alone, or dexfenfluramine and phentermine had a significantly higher prevalence of cardiac valvular insufficiency than a matched group of control subjects [14].
• CONCLUSIONS: Obese children under three years of age without obese parents are at low risk for obesity in adulthood, but among older children, obesity is an increasingly important predictor of adult obesity, regardless of whether the parents are obese [15].
• The adipocyte hormone, leptin (OB protein), is proposed to be an "adiposity signal" that acts in the brain to lower food intake and adiposity [16].
• Peripheral and central administration of microgram doses of OB protein reduced food intake and body weight of ob/ob and diet-induced obese mice but not in db/db obese mice [17].

Chemical compound and disease context of LEP

• ENPP1 Variants and Haplotypes Predispose to Early Onset Obesity and Impaired Glucose and Insulin Metabolism in German Obese Children [18].
• Chronic Treatment with Pioglitazone Does Not Protect Obese Patients with Diabetes Mellitus Type II from Free Fatty Acid-Induced Insulin Resistance [19].
• Relationship of Serum Interleukin-6 and Tumor Necrosis Factor alpha Levels with Abdominal Fat Distribution Evaluated by Ultrasonography in Overweight or Obese Postmenopausal Women [20].
• BACKGROUND: Obese premenopausal women are thought to be at low risk for osteoporosis due to increased body weight and effects of estrogen on weight-bearing bone [21].
• 5) Obese men have elevated levels of estrone and both free and total estradiol, and subnormal levels of free and total testosterone and of FSH; all these abnormalities are proportional to the degree of obesity [22].

Biological context of LEP

• Variations in the LEP and LEPR genes are associated with the magnitude of the effects of regular exercise on glucose homeostasis in nondiabetic individuals [23].
• The decrease in insulin was strongest in the LEP A19A homozygotes who carried the LEPR 109R allele [23].
• Leptin (LEP) and the uncoupling proteins 2 and 3 (UCP2/UCP3) are key molecules involved in the regulation of food intake and energy expenditure [3].
• We also demonstrated that both PRL and leptin (LEP) are capable of transactivation of the oncogenic receptors erbB2 and erbB3 [24].
• Leptin (OB protein), the product of the adipose-specific ob gene, exerts important effects in the regulation of food intake and energy expenditure [25].

Anatomical context of LEP

• Northern blot analysis revealed that OB RNA is present at a high level in adipose tissue but at much lower levels in placenta and heart [26].
• No increase in AdipoR1 gene expression was measured in myotubes derived from Obese, Diabetic, or Wt Loss subjects [27].
• Attention has focused on the hypothalamus as its potential site of action, but OB could also act on other brain regions [28].
• OBJECTIVE: Obstructive sleep apnoea syndrome (OSAS) is strongly associated with obesity (OB) and is characterized by several changes in endocrine functions, e.g. GH/IGF-I axis, adrenal and thyroid activity [29].
• 3H-ouabain concentration on erythrocytes (OBS) was also determined [30].

Associations of LEP with chemical compounds

• Therefore, the objective of the current study was to determine the mechanism of estrogen action on LEP promoter activation in divergent cell types [31].
• In OB women, IGF-I concentrations positively correlated with PRL (r = 0.31), testosterone (r = 0.30), androstenedione (r = 0.30), and dehydroepiandrosterone-sulfate (DHEAS) concentrations (r = 0.41) [32].
• Simultaneous evaluation of different neuroendocrine rhythms in these three groups revealed similar circadian abnormalities, (namely daytime persistence of melatonin secretion in AN and OB, and similar cortisol profile changes in AN and BN), together with evidence of internal desynchronization among the different bioperiodic functions [33].
• The arginine-induced insulin release in HP and OB was similar (4219.4 +/- 631.7 and 4107.3 +/- 643.2 mU x min x l(-1), respectively), both being higher (p < 0.02) than in NS (2178.1 +/- 290.9 mU x min x l(-1) [34].
• RESULTS: Obese rats had significantly higher (P < 0.05) body and liver weight, as well as plasma insulin, lactate, cholesterol, triglyceride and tumor necrosis factor (TNF)-alpha compared to their Ln counterparts [35].
• Contrarily, we found that dibutyryl cAMP counteracted hCG effect on leptin expression [36].

Regulatory relationships of LEP

• GH administration induced a similar plasma GH peak in NW and OB women (49.8 +/- 10.4 vs. 45.1 +/- 5.6 mU/liter) [37].
• These data suggest that TGF beta stimulates hOB cells to actively produce collagen matrix and proliferate [38].
• In the rat acute LEP administration enhances blood ACTH levels while prolonged treatment lowers blood corticotropin concentrations [39].
• CONCLUSIONS: This large family study shows that the rare T allele at the C538T polymorphism of LEP substantially influences pulse pressure and CIMT, but does not appear to exert this effect through actions on plasma leptin level or BMI [40].
• Serum Amyloid A and Obstructive Sleep Apnea Syndrome before and after Surgically-Induced Weight Loss in Morbidly Obese Subjects [41].
• Using deletion constructs of CYCLIN D1 promoter and chromatin immunoprecipitation assay, we show that leptin induced increase in CYCLIN D1 promoter activity is mediated through binding of activated Stat3 at the Stat binding sites and changes in histone acetylation and methylation [42].

Other interactions of LEP

• Basal ghrelin levels in NW were higher than in OB (P < 0.05) [43].
• METHOD: Obese and lean mice were treated with hGH, AOD or saline for 14 days using mini-osmotic pumps [44].
• These results demonstrate that OB protein can functionally antagonize and dominate the actions of exogenous NPY on feeding [45].
• Our results suggest that the LEP and UCP2/UCP3 genes are unlikely to have a substantial effect on variation in obesity phenotypes in this particular US Caucasian population [3].
• Circulating Serum Adiponectin Concentrations do not Differ between Obese and Non-obese Caucasians and are Unrelated to Insulin Sensitivity [46].

Analytical, diagnostic and therapeutic context of LEP

• Moreover, the presence of the LEP (-2548) A allele showed a significant association with decreased disease-free survival in breast carcinoma patients, and the presence of the LEPR 223R allele showed a significant association with decreased overall survival [5].
• OBJECTIVES: Because of their location in known candidate gene regions for obesity the associations between six microsatellite markers (D2S2170, D2S144, D2S1268, D2S1788, D2S1348 and a tetranucleotide repeat in the 3' UTR of the LEP locus) and body mass index (BMI) were studied in adult Samoans [47].
• RESEARCH METHODS AND PROCEDURES: Four distinct primary cell culture groups were established [Lean, Obese, Diabetic, Weight Loss (Wt Loss); n = 7 in each] from rectus abdominus muscle biopsies obtained from surgical patients [27].
• Our objective has been to conduct a population-based case-control study to estimate the risk of obesity arising from the -2548G > A and Q223R polymorphisms in the LEP and LEPR genes, respectively [8].
• To test the relevance of these observations to human obesity, the location of the human homologue (OB) was established by radiation hybrid mapping and eight microsatellite markers spanning the OB gene region (7q3l.3) were genotyped in 101 obese French families [48].

References