Perinatal exposure to a high-fat diet alters proopiomelanocortin, neuropeptide Y and dopaminergic receptors gene expression and the food preference in offspring adult rats / Exposição perinatal a uma dieta hiperlipídica altera a expressão gênica de proopiomelanocortina, neuropepitídeo Y e receptores dopaminérgicos e a preferência alimentar em ratos adultos descendentes

Exposure to the hight-fat diet may alter the control of food intake promoting hyperphagia and obesity. The objective of this study was to investigate the effects of this diet on dopamine receptors (drd1 and drd2), proopiomelanocortin (pomc), neuropeptideY (npy) genes expression, and preference food in adult rats. Wistar female rats were fed a hight-fat or control diet during pregnancy and lactation. The offspring were allocated into groups: Lactation Control (C) and High-fat (H). Post- weaning Control Control (CC), offspring of mothers C, fed a control diet after weaning; Control Hight-fat (CH), offspring of mothers C, fed a hight-fat diet after weaning; Hight-fat Control (HC), offspring of mothers H, fed with control diet after weaning; and Hight-fat Hight-fat (HH), offspring of mothers H, fed a H diet after weaning. The groups CH and HH presented greater expression of drd1 in comparison to the CC. The drd2 of CH and HC presented higher gene expression than did CC. HH presented higher pomc expression in comparison to the other groups. HC also presented greater expression in comparison to CH. The npy of HH presented greater expression in relation to CH and HC. HH and HC have had a higher preference for a high-fat diet at 102º lifes day. The high-fat diet altered the gene expression of the drd1, drd2, pomc and npy, and influencing the food preference for high-fat diet.(AU)

A exposição à dieta hiperlipídica pode alterar o controle da ingestão de alimentos, promovendo hiperfagia e obesidade. O objetivo deste estudo foi investigar os efeitos dessa dieta sobre a expressão gênica dos receptores de dopamina (drd1 e drd2), da proopiomelanocortina (pomc) e neuropeptídeo Y (npy), e preferência alimentar em ratos adultos. Ratas Wistar foram alimentadas com uma dieta hiperlipídica ou controle durante a gestação e lactação. Os descendentes foram alocados em grupos: Lactação Controle (C) e Hiperlipídica (H). Pós-desmame Controle Controle (CC), descendentes das genitoras do grupo controle e alimentados com dieta controle após o desmame; Controle Hiperlipídica (CH), descendentes das genitoras do grupo controle e alimentados com dieta hiperlipídica após o desmame; Hiperlipídica Controle (HC), descendentes das genitoras do grupo hiperlipídica e alimentados com dieta controle após o desmame; Hiperlipídica Hiperlipídica (HH), descendentes das genitoras do grupo hiperlipídica e alimentados com dieta hiperlipídica após o desmame. Os grupos CH e HH apresentaram maior expressão de drd1 em comparação ao CC. O drd2 de CH e HC apresentou maior expressão gênica que o CC. HH apresentou maior expressão de pomc em comparação com os outros grupos. O HC também apresentou maior expressão de pomc em comparação ao CH. O npy do HH apresentou maior expressão em relação ao CH e HC. HH e HC tiveram uma preferência maior por uma dieta rica em gordura no 102º dia de vida. A dieta hiperlipídica alterou a expressão gênica dos drd1, drd2, pomc e npy e influenciou na preferência alimentar pela dieta hiperlipídica.(AU)

Perinatal exposure to a high-fat diet alters proopiomelanocortin, neuropeptide Y and dopaminergic receptors gene expression and the food preference in offspring adult rats / Exposição perinatal a uma dieta hiperlipídica altera a expressão gênica de proopiomelanocortina, neuropepitídeo Y e receptores dopaminérgicos e a preferência alimentar em ratos adultos descendentes

Exposure to the hight-fat diet may alter the control of food intake promoting hyperphagia and obesity. The objective of this study was to investigate the effects of this diet on dopamine receptors (drd1 and drd2), proopiomelanocortin (pomc), neuropeptideY (npy) genes expression, and preference food in adult rats. Wistar female rats were fed a hight-fat or control diet during pregnancy and lactation. The offspring were allocated into groups: Lactation – Control (C) and High-fat (H). Post- weaning – Control Control (CC), offspring of mothers C, fed a control diet after weaning; Control Hight-fat (CH), offspring of mothers C, fed a hight-fat diet after weaning; Hight-fat Control (HC), offspring of mothers H, fed with control diet after weaning; and Hight-fat Hight-fat (HH), offspring of mothers H, fed a H diet after weaning. The groups CH and HH presented greater expression of drd1 in comparison to the CC. The drd2 of CH and HC presented higher gene expression than did CC. HH presented higher pomc expression in comparison to the other groups. HC also presented greater expression in comparison to CH. The npy of HH presented greater expression in relation to CH and HC. HH and HC have had a higher preference for a high-fat diet at 102º life’s day. The high-fat diet altered the gene expression of the drd1, drd2, pomc and npy, and influencing the food preference for high-fat diet.

A exposição à dieta hiperlipídica pode alterar o controle da ingestão de alimentos, promovendo hiperfagia e obesidade. O objetivo deste estudo foi investigar os efeitos dessa dieta sobre a expressão gênica dos receptores de dopamina (drd1 e drd2), da proopiomelanocortina (pomc) e neuropeptídeo Y (npy), e preferência alimentar em ratos adultos. Ratas Wistar foram alimentadas com uma dieta hiperlipídica ou controle durante a gestação e lactação. Os descendentes foram alocados em grupos: Lactação – Controle (C) e Hiperlipídica (H). Pós-desmame – Controle Controle (CC), descendentes das genitoras do grupo controle e alimentados com dieta controle após o desmame; Controle Hiperlipídica (CH), descendentes das genitoras do grupo controle e alimentados com dieta hiperlipídica após o desmame; Hiperlipídica Controle (HC), descendentes das genitoras do grupo hiperlipídica e alimentados com dieta controle após o desmame; Hiperlipídica Hiperlipídica (HH), descendentes das genitoras do grupo hiperlipídica e alimentados com dieta hiperlipídica após o desmame. Os grupos CH e HH apresentaram maior expressão de drd1 em comparação ao CC. O drd2 de CH e HC apresentou maior expressão gênica que o CC. HH apresentou maior expressão de pomc em comparação com os outros grupos. O HC também apresentou maior expressão de pomc em comparação ao CH. O npy do HH apresentou maior expressão em relação ao CH e HC. HH e HC tiveram uma preferência maior por uma dieta rica em gordura no 102º dia de vida. A dieta hiperlipídica alterou a expressão gênica dos drd1, drd2, pomc e npy e influenciou na preferência alimentar pela dieta hiperlipídica.

Early weaning by maternal prolactin inhibition leads to higher neuropeptide Y and astrogliosis in the hypothalamus of the adult rat offspring.

The suppression of prolactin production with bromocriptine (BRO) in the last 3 d of lactation reduces milk yield (early weaning) and increases the transfer of leptin through the milk, causing hyperleptinaemia in pups. In adulthood, several changes occur in the offspring as a result of metabolic programming, including overweight, higher visceral fat mass, hypothyroidism, hyperglycaemia, insulin resistance, hyperleptinaemia and central leptin resistance. In the present study, we investigated whether overweight rats programmed by early weaning with maternal BRO treatment have hypothalamic alterations in adulthood. We analysed the expression of neuropeptide Y (NPY), cocaine- and amphetamine-regulated transcript (CART), pro-opiomelanocortin (POMC) and α-melanocyte-stimulating hormone (α-MSH) by immunohistochemistry in the following hypothalamic nuclei: medial and lateral arcuate nucleus (ARC); paraventricular nucleus (PVN); lateral hypothalamus (LH). Additionally, we sought to determine whether these programmed rats exhibited hypothalamic inflammation as indicated by astrogliosis. NPY immunostaining showed a denser NPY-positive fibre network in the ARC and PVN (+82% in both nuclei) of BRO offspring. Regarding the anorexigenic neuropeptides, no difference was found for CART, POMC and α-MSH. The number of astrocytes was higher in all the nuclei of BRO rats. The fibre density of glial fibrillary acidic protein was also increased in both medial and lateral ARC (6·06-fold increase and 9·13-fold increase, respectively), PVN (5·75-fold increase) and LH (2·68-fold increase) of BRO rats. We suggest that early weaning has a long-term effect on the expression of NPY as a consequence of developmental plasticity, and the presence of astrogliosis indicates hypothalamic inflammation that is closely related to overweight and hyperleptinaemia observed in our model.

Early weaning is associated with higher neuropeptide Y (NPY) and lower cocaine- and amphetamine-regulated transcript (CART) expressions in the paraventricular nucleus (PVN) in adulthood.

The interruption of lactation for a short period, without the use of pharmacological substances or maternal separation, causes offspring malnutrition and hypoleptinaemia and programmes for metabolic disorders such as higher body weight and adiposity, hyperphagia, hyperleptinaemia and central leptin resistance in adulthood. Here, in order to clarify the mechanisms underlying the phenotype observed in adult early-weaned (EW) rats, we studied the expression of neuropeptide Y (NPY), agouti-related peptide (AgRP), pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) in different hypothalamic nuclei by immunohistochemistry and Western blot. In the EW group, the teats of lactating rats were blocked with a bandage to interrupt lactation during the last 3 d, while control pups had free access to milk throughout the entire lactation period. At age 180 d, EW offspring showed higher NPY staining in the paraventricular nucleus (PVN), as well as NPY protein content (+68 %) in total hypothalamus than control ones. AgRP showed no changes in staining or Western blot. POMC content was not affected; however, its distribution pattern was altered. CART-positive cells of EW offspring had lower immunoreactivity associated with reduced cell number in the PVN and lower protein content ( - 38 %) in total hypothalamus. The present data indicate that precocious weaning can imprint the neuronal circuitry, especially in the PVN, and cause a long-term effect on the expression of specific orexigenic and anorexigenic neuropeptides, such as NPY and CART, that can be caused by leptin resistance and are coherent with the hyperphagia observed in these animals.

Identification of neuronal enhancers of the proopiomelanocortin gene by transgenic mouse analysis and phylogenetic footprinting.

The proopiomelanocortin (POMC) gene is expressed in the pituitary and arcuate neurons of the hypothalamus. POMC arcuate neurons play a central role in the control of energy homeostasis, and rare loss-of-function mutations in POMC cause obesity. Moreover, POMC is the prime candidate gene within a highly significant quantitative trait locus on chromosome 2 associated with obesity traits in several human populations. Here, we identify two phylogenetically conserved neuronal POMC enhancers designated nPE1 (600 bp) and nPE2 (150 bp) located approximately 10 to 12 kb upstream of mammalian POMC transcriptional units. We show that mouse or human genomic regions containing these enhancers are able to direct reporter gene expression to POMC hypothalamic neurons, but not the pituitary of transgenic mice. Conversely, deletion of nPE1 and nPE2 in the context of the entire transcriptional unit of POMC abolishes transgene expression in the hypothalamus without affecting pituitary expression. Our results indicate that the nPEs are necessary and sufficient for hypothalamic POMC expression and that POMC expression in the brain and pituitary is controlled by independent sets of enhancers. Our study advances the understanding of the molecular nature of hypothalamic POMC neurons and will be useful to determine whether polymorphisms in POMC regulatory regions play a role in the predisposition to obesity.

Anorexia in rats infected with the nematode, Nippostrongylus brasiliensis: experimental manipulations.

Nippostrongylus brasiliensis induces a biphasic anorexia in laboratory rats, the first phase coincident with lung invasion (ca day 2) and the second when the worms mature in the intestine (ca day 8). Using the anthelminthic, mebendazole (MBZ), N. brasiliensis infections of the rat were eliminated between the first and second anorexic episodes. This intervention prevented the expression of the second phase of anorexia. Rats exposed to a second infection with N. brasiliensis, 3 weeks after the primary infection, exhibited only a first phase anorexic response which was not influenced by MBZ termination of the primary infection. The lower cumulative food intake and weight gain of all infected rats after 8 days of infection were accompanied by elevated plasma insulin and, in some individuals, by elevated plasma leptin, compared with uninfected controls and previously-infected MBZ-treated rats. Messenger RNA levels for neuropeptide Y were higher in the hypothalamic arcuate nucleus of 8-day infected rats than in recovering MBZ-treated animals. Inoculation of rats with heat-killed N. brasiliensis larvae failed to induce anorexia and did not alter the severity of biphasic anorexia on subsequent injection of viable larvae. The first anorexic episode is therefore dependent upon viable migrating larvae. The second phase of anorexia clearly requires the continuing presence of the parasite beyond the lung phase. Viable migrating larvae are also required to confer 'resistance' to reinfection.

Corticotropin-releasing factor and vasopressin production in the rat pituitary tumor 7315a: biochemical and immunohistochemical studies.

In order to investigate the production and secretion of hypothalamic factors by the prolactin and proopiomelanocortin (POMC)-derived, peptide-producing, transplantable rat pituitary tumor 7315a, we determined the concentrations of corticotropin-releasing factor (CRF)- and vasopressin (AVP)-like immunoreactivities (IR) in the tumor extracts [14.0 +/- 1.6 (SE) and 4.2 +/- 0.9 pmol/g, respectively] and incubation media (0.26 +/- 0.01 and 0.07 +/- 0.01 pmol/10(7) cells/h, respectively). Total peptide content correlated well with tumor weight. Moreover, there is a very good correlation between the CRF and AVP IR, but not as good between CRF or AVP IR and POMC peptide IR tumor contents. Tumor extracts were chromatographed on Sephadex G-75 and compared with chromatograms of stalk median eminence (SME) extracts from normal Buffalo rats. CRF IR in tumor chromatograms gave an unusual pattern of peaks. About 31% of the total CRF IR was eluted in the high molecular weight region. The major portion of CRF IR was located in a wide region of lower molecular weight. The AVP radioimmunoassay revealed a similar pattern of peaks in tumor and SME chromatograms. A propressophysin-like peak and a smaller peak coeluting with synthetic AVP were detected. Immunohistochemical staining of consecutive sections of the tumor indicated that AVP and CRF are often found in the same cell, but the CRF and AVP-producing cells are clearly distinct from the POMC peptide-producing cells.