A composição corporal, resistência à leptina e função tireóidea são programadas em ratos cujas mães foram tratadas com leptina no início da lactação

• Autor(a) principal: Toste, Fernanda Pereira
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/12774
• topic: Programming; Leptin; lLptin resistance; Thyroid function; Body composition; Resistência à insulina; HOMA; Sensibilidade à insulina; Perda de peso; Circunferência da cintura; Relação cintura quadril; Composição corporal; Baixo índice glicêmico; CNPQ::CIENCIAS BIOLOGICAS::FISIOLOGIA::FISIOLOGIA DE ORGAOS E SISTEMAS::FISIOLOGIA ENDOCRINA

Pup´s leptin injection on the first 10 days of lactation programmes for higher food intake (FI), body mass (BM), lean mass, thyroid function, hyperleptinemia and resistance to its action and lower leptin receptor (ObRb) expression on 150 days-old rats. When mothers were leptin-treated on the last 3 days of lactation, it seems to reproduce partially this programming effect, except for higher visceral fat mass (VFM). So, we evaluated the offspring metabolic phenotype when the mothers were treated with leptin in the first 10 days of lactation. On birth, the lactating Wistar rats were divided into: Leptin (LEP) treated with recombinant leptin (8mg/100g, PC, sc) for the first 10 days of lactation and Control (C) saline-treated in the same conditions. The mothers´ BM and FI were monitored daily and they were milked at the 21st day of lactation. LEP mothers had lower BM during lactation (~6%, p <0.05) and normal FI. The mothers sacrifice occurred to the end of lactation. The leptin concentration of LEP mothers was normal in serum and milk, while T3 was normal in serum and higher in milk (+30%, p <0.05). The offspring BM and FI was monitored daily and accompanied by 4 on 4 days after weaning until 180 days of age. The LEP offspring had lower BM during lactation (~5%, p<0.05) and from the day 69 onward higher BM (+10%, p<0.05), while the FI was higher (+17%, p<0.05) at day 145 onward. The leptin resistance test was performed at 30 and 180 days. Both group was subdivided into: CLEP and LEPLEP treated with leptin (0.5 mg / kg / ip PC); CSAL and LEPSAL treated with saline. The animals were sacrificed at 21, 30 and 180 days. We collected the VFM, carcass, blood (glycemia, leptin, total T3 and T4, TSH, insulin) and liver (GPDm activity). LEP offspring had higher T3 at 21 days, but not significant (p = 0.06) and when they were 30 days-old they already present leptin resistance and lower serum T3 (-20%,p<0.05). At 180 days they had higher VFM (+57%, p<0.05), total body fat (+40%, p<0.05), leptin resistance, hyperleptinemia (+1,35x, p<0.05) with normal 125I thyroid uptake, serum T4 and TSH and lower GPDm activity at 30 and 180 day (-42% and -57%,p< 0.05 respectively). So, the mother's hyperleptinaemia in the beginning of lactation programs as early as the 30 days-old offspring: leptin resistance and hypothyroidism, probably by a higher leptin transfer through the milk. We suggested that the levels of leptin in early lactation are determinants of the physiological regulation of energy balance in adulthood. We suggest that the programming effects are dependent on the way that leptin reaches the offspring. The present study seems more physiological and reproduces almost completely the programming effect in the adulthood when the mothers were leptin-injected at the end of lactation and, partially reproduces the effects when leptin was directally injected in the pups.