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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Biosciences & Biotechnology Laboratory » Research » Publications at this Location » Publication #341001
Title: Insulin immuno-neutralization decreases food intake in chickens without altering hypothalamic mRNA levels for genes involved in regulation of food intake and metabolism

Author
item Proszkowiec-Weglarz, Monika
item DUPONT, JOELLE - Institut National De La Recherche Agronomique (INRA)
item RIDEAU, NICOLE - Institut National De La Recherche Agronomique (INRA)
item GESPACH, CHRISTIAN - Institut National De La Recherche Agronomique (INRA)
item SIMON, JEAN - Institut National De La Recherche Agronomique (INRA)
item PORTER, TOM - University Of Maryland

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/10/2017
Publication Date: 9/25/2017
Citation: Proszkowiec-Wegla, M.K., Dupont, J., Rideau, N., Gespach, C., Simon, J., Porter, T.E. 2017. Insulin immuno-neutralization decreases food intake in chickens without altering hypothalamic mRNA levels for genes involved in regulation of food intake and metabolism. Poultry Science. http://dx.doi.org/10.3382/ps/pex247.

Interpretive Summary: In mammals, insulin regulates blood glucose level but also plays a key role in appetite regulation at the level of the hypothalamus. In contrast to mammals, chickens are characterized by relatively high blood glucose levels and large resistance to exogenous insulin. The aim of the present study was to investigate effects of fasting for 5 h and the injections of antiserum to insulin (insulin-immuno-neutralization) on selected gene expression levels associated with food intake, energy balance, and glucose metabolism in the chicken hypothalamus. Injections of antiserum to insulin decreased feed intake and increased plasma glucose levels in chickens, while 5 h fasting only slightly decreased plasma glucose levels. Surprisingly, insulin antiserum had no effect on gene expression of any of selected genes. In contrast, 5 h fasting altered expression of genes related to feed intake control as well as glucose transporters in hypothalamus in chickens. Therefore the feed intake inhibition or “satiety” regulating mechanism induced by insulin antiserum injections does not rely on changes at the level of gene expression but most likely on changes in glucose sensing or metabolism and/or a decrease in insulin signaling. However, the short period of fasting (5 hr) had an effect on the gene expression level.

Technical Abstract: Chickens are characterized by rather unique glucose homeostasis, with relatively high blood glucose levels, reduced glucose sensitivity of pancreatic cells, and large resistance to exogenous insulin. In mammals, insulin regulates blood glucose level but also plays a key role in appetite regulation at the level of the hypothalamus. The aim of the present study was to investigate effects of 5h-fasting and 5h-insulin immuno-neutralization in chickens using an antiserum to insulin (AI) on mRNA levels of 23 selected genes associated with food intake, energy balance, and glucose metabolism in the chicken hypothalamus. AI significantly decreased food intake and increased plasma glucose levels, while 5h-fasting only slightly and non-significantly decreased plasma glucose levels. Most other plasma metabolic and endocrine changes were observed in both experimental groups. AI had no effect on the levels of any selected mRNA. In contrast, 5h fasting altered mRNA expression of NPY, TAS1R1, DIO2, LEPR, GLUT1, GLUT3, GLUT8, and GCK. Therefore the food intake inhibition or “satiety” mechanism induced by insulin immuno-neutralization does not rely on changes at the level of transcript abundance (within the 5-hrperiod investigated) but most likely on changes in glucose sensing or metabolism and/or a decrease in insulin signaling. In contrast, the short period of fasting (5 hr) had an effect at the transcript level. The “fast responder” genes presently identified, which are involved in food intake, glucose transport, and metabolism, are likely components of a mechanism of emergency adaptation to fasting.