Enhanced food intake by progesterone-treated female rats is related to changes in neuropeptide genes expression in hypothalamus

Wstęp: Podanie progesteronu samicom szczura prowadzi do wzrostu ilości spożywanego przez nie pokarmu, jednak mechanizmy odpowiedzialne za ten efekt nie są do końca znane. Celem tej pracy było sprawdzenie, czy obserwowane pod wpływem progesteronu zmiany w ilości spożywanego pokarmu przez szczury mogą być związane ze zmianami ekspresji genów neuropeptydów w podwzgórzu.Materiał i metody: Doświadczenie zostało przeprowadzone na samicach i samcach szczura rasy Wistar. Po 28 dniach po podaniu progesteronu (100 mg/szczura) pobrano podwzgórza i zmierzono poziom mRNA NPY i CART w oparciu o metodę PCR w czasie rzeczywistym. Stężenie progesteronu w surowicy krwi badanych zwierząt oznaczono metodą radioimmunologiczną.Wyniki: Podanie progesteronu prowadzi do wzrostu masy ciała, tkanki tłuszczowej i ilości spożywanego pokarmu u samic szczura. Zmianom tym towarzyszy wzrost ekspresji genu NPY i obniżenie ekspresji genu CART w podwzgórzu. U samców podanie progesteronu nie ma wpływu na masę ciała, masę tkanki tłuszczowej i ilość spożywanego pokarmu oraz ekspresję genów neuropeptydów w podwzgórzu. Ponadto wykazano, że podanie progesteronu samicom szczura prowadzi do obniżenia ekspresji genu receptora progesteronowego w podwzgórzu. Zmian takich nie zaobserwowano u samców.Wnioski: Zmiany ekspresji genów neuropeptydów w podwzgórzu samic szczura, którym podano progesteron, mogą prowadzić do stymulacji apetytu, co w konsekwencji wpływa na wzrost ilości spożywanego pokarmu, zwiększenie masy ciała i masy tkanki tłuszczowej. (Endokrynol Pol 2014; 65 (1): 46–53)Introduction: Progesterone-treated females eat more food, but the mechanism underlying this effect is not well understood. The aim of the study was to analyse the effect of progesterone on neuropeptide genes expression in rat hypothalamus.Material and methods: Experiments were carried out on female and male Wistar rats. Animals were treated with progesterone (100 mg per rat) for 28 days. NPY and CART mRNA levels in hypothalamus were quantified by real-time PCR. The serum progesterone concentration was determined by radioimmunoassay.Results: Progesterone administration to females caused an increase in food intake, body mass, and white adipose tissue mass. Elevated circulating progesterone concentration up-regulated NPY and down-regulated CART genes expression in hypothalamus of females. In males, elevated blood progesterone concentration had no effect on food intake, body and fat mass and on the neuropeptide genes expression in hypothalamus. Moreover, administration of progesterone in females resulted in decrease of PR mRNA level in hypothalamus. No effect of progesterone administration on PR mRNA level in hypothalamus of males was found.Conclusions: The changes in neuropeptide genes expression in hypothalamus may lead to stimulation of appetite and might explain the observed increase in food intake, body and adipose tissue mass in progesterone-treated females. (Endokrynol Pol 2014; 65 (1): 46–53

Modulatory Effects of Breed, Feeding Status, and Diet on Adipogenic, Lipogenic, and Lipolytic Gene Expression in Growing Iberian and Duroc Pigs

Meat quality depends on tissue composition which is in turn influenced by different factors, such as diet, genotype, age, or sex. We evaluated the effects of breed, 24 h fasting, and dietary energy source (HO: oleic acid versus CH: carbohydrates) on the expression of candidate genes involved in adipogenesis, lipogenesis, and lipolysis in the adipose tissue from Iberian and Duroc growing pigs. The Iberian pigs showed greater feed intake, backfat thickness, and saturated fatty acids (SFA) content in the subcutaneous fat, whereas the Duroc pigs had greater ham weight and polyunsaturated fatty acids (PUFA) content. In both breeds, the diet induced changes in the fatty acid (FA) composition of subcutaneous fat samples. The HO group had higher monounsaturated fatty acids (MUFA) and oleic acid, and lower SFA than the CH group. Regarding gene expression, breed and feeding status (fasting versus postprandial) had significant effects on gene expression, with quantitative interactions between them, while diet showed negligible effects. In general, adipogenic and lipogenic genes were upregulated in the Iberian pigs and in postprandial samples. In contrast, the expression of lipolytic genes showed complex interaction effects. Our results agree with the phenotypic differences between the Iberian and Duroc breeds and with the inhibition of lipogenesis by fasting. Quantitative interactions between breed and feeding status effects were observed, which indicates a different response to fasting of the two breeds, with the obese Iberian breed showing a more stable expression of lipogenic genes. These results highlight the complexity of lipid metabolism regulation, especially in relation to lipolysis processes