Background: Leptin, the product of the obesity (ob) gene, acts as a signaling adipokine for modulating food intake, energy metabolism and reproductive functions in mammals. Leptin’s effects on the reproductive system at various levels of the hypothalamic-pituitary-gonadal axis have been established. Moreover, the direct and local effect of leptin on bovine oocyte maturation and corpus luteum fu...

Background: Many hormones are involved in the regulation of reproduction. Leptin hormone which is mainly secreted by adipose tissue plays an important role in energy homeostasis and reproduction. It seems that leptin is an important linkage between body metabolism and reproductive system. Moreover, it has been shown that leptin and leptin receptor express in reproductive organs of some species....

Background: The present study aimed to investigate the presence of leptin mRNA transcript in epididymal spermatozoa of Holstein cattle by RT-PCR analysis. Materials and Methods: To collect sperm from epididymis, the whole testes of three adult Holstein bulls were quickly removed after slaughtering. Samples were transferred to the laboratory on ice and subsequently the epididymal contents were c...

Leptin, the product of the ob gene, is involved in the control of ovarian functions. Leptin transcripts and OB proteins were localized in the porcine corpus luteum, but the regulatory mechanism of leptin mRNA expression and leptin secretion in porcine luteal cells remains unexplained. The aim of the present study was to: 1) determine level of leptin and long form of leptin receptor (OB-Rb) tran...

Leptin has been shown to exert positive effects during the maturation of bovine oocytes, influencing blastocyst development, apoptosis, and the transcript levels of developmentally important genes. The present study was conducted to characterize further the mechanisms of leptin action on oocytes and the role of cumulus cells (CCs) in this context. In the first series of experiments, cumulus-ooc...

Seasonal Siberian hamsters lose fat reserves, decrease body weight and leptin concentrations, and suppress reproduction on short-day photoperiod (SD). Chronic leptin infusion at physiological doses caused body weight and fat loss in SD animals but was ineffective in long-day (LD) hamsters. Using ovariectomized estrogen-treated females, we tested the hypothesis that responsiveness to leptin is r...

The leptin receptor (OB-R) is a single membrane- spanning protein that mediates the weight-regulatory effects of leptin (OB protein). Several mRNA splice variants have been described which either encode OB-R proteins with cytoplasmic domains of different length or the OB-R and B219/OBR variants, which have different 5'-untranslated regions. Here we report evidence for the synthesis of a human m...

The reductions in circulating levels of leptin, insulin, and glucose with fasting serve as important homeostasis signals to neurons of the hypothalamic arcuate nucleus that synthesize neuropeptide Y (NPY)/agouti-related protein (AGRP) and alpha-MSH/cocaine and amphetamine-regulated transcript. Because the central administration of leptin is capable of preventing the inhibitory effects of fastin...

Leptin receptors are distributed throughout the body and leptin has been shown to have various effects. As we have recently demonstrated a positive correlation between serum leptin levels and TSH in euthyroid subjects, we investigated the effect of leptin on the thyroids. It was observed that serum leptin levels were negatively correlated with free thyroxine/TSH ratios in the serum of euthyroid...

BACKGROUND/AIMS Alzheimer's disease (AD) is known to be related to alterations in neuronal intracellular calcium activity ([Ca2+]i). The present study revealed the distinct role of leptin in Na+/Ca2+-exchanger activity. METHODS [Ca2+]i was determined utilizing Fura-2 fluorescence. The activity of NCX was measured by removal of extracellular Na+ in the presence of external Ca2+. Na+/Ca2+-excha...