Leptin, the peptide hormone product of the ob gene, regulates food intake and energy expenditure at the hypothalamic level via the long-form of the leptin receptor (Ob-Rb). Leptin also plays a key role in determining the onset of puberty, but there is controversy as to whether leptin provides a trigger for puberty or is a permissive signal. Thus, although leptin administration can advance puber...

Leptin is a multifunctional regulator in numerous tissues, including the pituitary. It is not known, whether the porcine pituitary is a source of leptin synthesis and possesses the leptin receptor protein. It is also unknown, if a relationship exists between expression levels of these proteins in the pituitary and physiological status of sows. Therefore, the aim of the study was 1] to examine, ...

The Retinoblastoma protein, Rb, was shown to regulate distinct aspects of neurogenesis in the embryonic and adult brain besides its primary role in cell cycle control. It is still unknown, however, whether Rb is required for tissue morphogenesis and the establishment of synaptic connections between adjacent tissues during development. We have investigated here the role of Rb during development ...

This experiment was designed to investigate leptin receptors (Ob-R and Ob-Rb) mRNA in ram epididymal spermatozoa by RT-PCR. Ten testes were obtained from abattoir and epididymal spermatozoa recovery was performed. To purify spermatozoa, motile sperm were isolated by the swim-up procedure. Total RNA was isolated from epididymal spermatozoa and placental cotyledon, as a positive control, and then...

The expression and localization of long-form leptin receptor (OB-Rb) were studied immunocytochemically in the brain of fetal and adult rats using a polyclonal antibody that specifically recognized OB-Rb. At 14 days of gestation, immunoreactive cells were observed in the ventricular layer, which contains premature neuronal cells. At 18 days of gestation, they were weakly stained but obvious in t...

Adult neural stem cells (aNSCs) are relatively quiescent populations that give rise to distinct neuronal subtypes throughout life, yet, at a very low rate and restricted differentiation potential. Thus, identifying the molecular mechanisms that control their cellular expansion is critical for regeneration after brain injury. Loss of the Retinoblastoma protein, Rb, leads to several defects in ce...

Leptin or obesity receptor (Ob-R) is a member of class I cytokine receptor family. Ob-R, expressed in six isoforms, is the product of alternative RNA splicing of db gene. According to its structural differences, the receptor's isoforms are divided into three classes: long, short, and secretory isoforms. A long, fully active isoform of Ob-Rb is expressed mainly in the hypothalamus, where it take...

Leptin and its long form receptor, Ob-Rb, in the hypothalamus play a key function in regulating food intake and body weight. We demonstrate here that apolipoprotein D (Apo D), a lipocalin that is heavily expressed in brain, interacts specifically with the cytoplasmic portion of Ob-Rb but not the short form receptor, Ob-Ra. This finding is detected in yeast two-hybrid systems as well as in prote...

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...

Leptin, a hormone secreted by adipocytes, plays an important role in the regulation of metabolism and reproduction. The effect of leptin is mediated mainly via the long isoform of the leptin receptor (OB-Rb). Expression of leptin and its receptor has been identified in the central nervous system (hypothalamus, pituitary) and reproductive tract (uterus, ovary and placenta) in prepubertal gilts. ...