Thyrotropin-releasing hormone regulates the diurnal variation of pyroglutamyl aminopeptidase II activity in the male rat adenohypophysis

Vargas, Miguel; Uribe, R.M.; Cisneros, Miguel; Romero, Fidelia; González, Sergio; Joseph‐Bravo, Patricia; Charlí, Jean-Louis

doi:10.1530/eje.0.1470363

Cited by 12 publications

References 31 publications

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A possible role of neuropeptide Y, agouti-related protein and leptin receptor isoforms in hypothalamic programming by perinatal feeding in the rat

et al. 2004

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Aim/hypothesis: Perinatal overfeeding predisposes humans and rats to obesity and diabetes in later life. One classical model for studying the effect of early feeding is manipulation of the size of rat litters. Rats growing up in small litters gain more weight than rats growing up in normal-sized litters. Interestingly, these obese rats maintain this phenotype in adulthood. Conversely, rats raised in large litters show a delay in growth and a decrease in body weight. The aim of this work was to assess the hypothalamic control mechanisms of food intake regulated by perinatal feeding. Methods: Leptin levels were analysed using RIA. Leptin receptor mRNA levels were analysed using RT-PCR. Neuropeptide mRNA levels were analysed using in situ hybridisation. Results: Perinatally overfed neonatal male rats exhibited hyperleptinaemia and a decrease in hypothalamic mRNA levels of the long isoform of the leptin receptor (OB-Rb), explaining their leptin resistance. Moreover, this obese model showed an increase in the mRNA expression of cocaine-and amphetamine-regulated transcript, neuropeptide Y and agouti-related protein in the hypothalamic arcuate nucleus (ARC). In contrast, perinatally underfed neonatal male rats with hypoleptinaemia showed an increase in hypothalamic mRNA of the short isoforms of the leptin receptor. Furthermore, they exhibited an increase in expression of neuropeptide Y and agoutirelated protein in the ARC. Conclusions/interpretation: Rats overfed during early postnatal life show a leptinresistant state mediated by down-regulation of the hypothalamic OB-Rb. These data, together with the increased expression of neuropeptide Y and agouti-related protein in specific neurons in the ARC, might indicate the existence of regulated programming in this nucleus and may provide a new aetiopathogenic concept in susceptibility to obesity.

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A possible role of neuropeptide Y, agouti-related protein and leptin receptor isoforms in hypothalamic programming by perinatal feeding in the rat

et al. 2004

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A Group of Weakly Bound to Neurons Extracellular Metallopeptidases (NEMPs)

Kropotova

Mosevitsky

2016

Neurochem Res

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We have found that isolated from mammalian brain (rat, bovine) axonal endings (synaptosomes) degrade peptides of different composition. With the use of low concentration of non ionic detergent Triton X-100 (0.05-0.1 %) four low specific metallopeptidases were detached from synaptosomes. These peptidases were named Neuronal EctoMetalloPeptidases (NEMPs). Using specially designed test-peptides they were characterized as: carboxypeptidase (NEMP1), aminopeptidase (NEMP2) and endopeptidases NEMP3 and NEMP4. NEMPs are true peptidases (oligopeptidases), because they are able efficiently degrade peptides containing less than 40 amino acid residues. Specific properties of some NEMPs were revealed. NEMP1 is a small protein (molecular mass of about 10 kDa), which tends to dynamic oligomerization. NEMP3 needs activation. Some amino acids activate this enzyme. As far as we know, these properties were not ascribed to the known similarly localized peptidases. A possible physiological function of low specific NEMPs is participation in control of wide range of neuropeptides secreted in the synaptic cleft. However, NEMPs also due to their low specificity can destroy introduced in brain therapeutic peptides. The data obtained in this study open new opportunities for the protection of synthetic therapeutic peptides in brain and, possibly, in other tissues.

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