leptin is secreted mainly by fat, which is involved in energy metabolism and reproduction. leptin and itsreceptor (ob-r) have been detected in human spermatozoa and testis, thus it can be concluded leptin involves in male physiology. the goal of this study was determination of the presence of leptin receptor mrna in the ram testis, epididymis and spermatozoa by reverse transcription polymerase ...

Leptin is secreted mainly by fat, which is involved in energy metabolism and reproduction. Leptin and itsreceptor (Ob-R) have been detected in human spermatozoa and testis, thus it can be concluded leptin involves in male physiology. The goal of this study was determination of the presence of leptin receptor mRNA in the ram testis, epididymis and spermatozoa by reverse transcription polymerase ...

Leptin receptors are constitutively endocytosed in a ligand-independent manner. To study their endocytosis, leptin receptors OB-Ra and OB-Rb were expressed in HeLa cells. Both receptor isoforms were ubiquitylated, internalized by clathrin-mediated endocytosis and transported to Hrs-positive endosomes after their internalization. Proteasome inhibitors inhibited OB-Ra but not OB-Rb internalizatio...

Mutations of the leptin receptor have been found to cause obesity in rodents. The fa mutation that is responsible for obesity in Zucker rats is a missense mutation (269 gln-->pro) in the extracellular domain of the leptin receptor. We have characterized the effects of this mutation on the two major isoforms of the leptin receptor, Ob-Rb and Ob-Ra, by studying cell-surface expression, leptin bin...

Obesity and type 2 diabetes are associated with nonalcoholic steatohepatitis (NASH), but an obese/diabetic animal model that mimics human NASH remains undefined. We examined the induction of steatohepatitis and liver fibrosis in obese and type 2 diabetic db/db mice in a nutritional model of NASH and determined the relationship of the expressions of osteopontin (OPN) and leptin receptors to the ...

We investigated the effects of lactation on diurnal changes in serum leptin and hypothalamic expression of the leptin receptor isoforms, Ob-Ra, -Rb, -Rc, -Re and -Rf in rats. In non-lactating rats, serum leptin concentration was increased at night while hypothalamic mRNA levels of Ob-Rb, -Rc and -Re decreased; by contrast, expression of Ob-Ra and Ob-Rf was unchanged at night. There were signifi...

To explore the regulation of CX3CL1 in inflammatory bone diseases, CX3CL1 expression by osteoblasts (OB) was examined. Human OB isolated from rheumatoid arthritis (RA) patients, osteoarthritis patients, and normal individuals were incubated in the presence of cytokines. Soluble CX3CL1 levels were determined with an enzyme-linked immunosorbent assay. Expression of CX3CL1 mRNA was examined using ...

Plasma leptin concentrations increase as growing dairy heifers approach puberty and have greater plasma estrogen. In intact and ovariectomized rodents, estrogen has been shown to modulate expression of leptin and its receptor (Ob-R). To determine if estrogen regulates the bovine leptin system, prepubertal dairy heifers were ovariectomized at 140 d of age or left intact. A month later, both grou...

The antiobesity effects of leptin are mediated by the obese receptor (OB-R), a member of the cytokine receptor superfamily. Several isoforms of OB-R that differ in the length of the cytoplasmic domain have been described. An isoform with a long cytoplasmic domain of 302 amino acids, termed OB-Rb, contains the conserved box 1 and box 2 motifs and is likely to be responsible for leptin-induced si...

Leptin is an adipose tissue-secreted hormone that acts via specific receptors (Ob-R), of which six isoforms are at present recognized (from Ob-Ra to Ob-Rf). Ob-Rb is the only isoform able to activate JAK-STAT and MAPK signaling cascades. A large body of evidence suggests that leptin and its receptors are involved in prostate physiology and pathophysiology in humans, but studies on the leptin sy...