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Neuropeptide Y-related peptides and feeding: Evidence for multiple receptor interactions in the hindbrain
ABSTRACTS
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of flumazenil, a BZR antagonist. These results can be related to recent proposals that BZs enhance the palatability of taste and possibly other food-related stimuli.
Neuropeptide Y-related Peptides and Feeding: Evidence for Multiple Receptor Interactions in the Hindbrain. E. S. CORP and G. P. SMITH. Bourne Laboratory, Cornell University Medical College, White Plains, NY 10605, U.S.A. To determine the specific neuropeptide Y (NPY) receptor involved in the orexigenic effects of NPY, we compared the potency and efficacy with which NPY-related peptides elicit food intake following fourth ventricular administration. The peptides tested include: NPY [YI, Y2 and Y3 receptor activity]; peptide YY (PYY) [YI and Y2 activity]; [Leu 3~, Pro34]NpY (LPNPY) [Y1 and Y3 selective]; NPYI3 36 [Y2 selective]; and NPY2-36 [Y2>>Y1]. Based on halfmaximal and maximal response, PYY was the most potent peptide tested. At low doses, NPY2-36 was as potent as PYY, and more potent than NPY. At higher doses, however, NPY2-36 showed a reduced efficacy (50% of the maximal elicited by PYY) that was apparent across a broad range of doses tested. The YI selective agonist, LP-NPY was less potent and 50% less efficacious than PYY. The Y2 selective agonist, NPYI3_36 was the weakest agonist tested. Potency and efficacy data support the hypothesis that two NPY receptor subtypes are implicated in the stimulation of feeding induced by NPY-related peptides acting in the hindbrain. (Supported by The Whitehall Foundation).
The Effects of Sucrose and Aspartame on Hunger, Taste Preferences and Energy Intakes in Lean and Obese Women. A. DREWNOWSKI, J. LOUIS-SYLVESTRE, C. MASSIEN, J. FRICKER, D. CHAPELOT and M. APFELBAUM. Human Nutrition Program, University of Michigan School of Public Health, Ann Arbor, U.S.A. and INSERM U286, Nutrition Humaine, Faculte de Medecine X. Bichat, Paris, France. The effects of four breakfast preloads on motivational ratings, taste preferences, and energy intakes were examined in 12 lean and 12 massively obese but non-dieting women. The breakfasts, consumed at 0930 hrs consisted of 400 g of sweetened creamy white cheese ("fromage blanc"). Two high-calorie breakfasts (700 kcal) contained either sucrose or maltodextrin with aspartame, while low calorie ones (300 kcal) were aspartame-sweetened or plain. The study followed a within-subject design, with subjects serving as their own controls. Taste preferences for sugar/fat stimuli were measured both before and 2.5 h after breakfast. Hunger ratings were measured every 30 min. The subjects were served three buffet-style meals: lunch (1230 hrs), snack (1600 hrs) and dinner (1900 hrs), always composed of the same 21 foods. As expected, consumption of 300 kcal as opposed to 700 kcal led to more elevated hunger ratings later on, and the consumption of more calories at lunch. However, daily energy intakes exclusive of breakfast (lean women: 1484 kcal; obese women: 2596 kcal) were the same for all four preloads. No caloric compensation was observed by the end of the day: women who consumed 300kcal breakfasts had lower caloric intakes that day. There was no evidence that intense sweeteners promote hunger or result in increased energy intakes in lean or in obese women.
Prediction of Basal Energy Expenditure from Organ Weights in the Rat. P. C. EVEN, A. PELE and S. NICOLAIDIS. Laboratoire de Neurobiologie, CNRS URA 1860, Coll~ge de France, 11 PI. Berthelot 75005 Paris. The problem of matching energy expenditure to body mass, or to its various correlates, always prevented the creation of a predictive equation reliable enough to reveal subtle changes that
79
of flumazenil, a BZR antagonist. These results can be related to recent proposals that BZs enhance the palatability of taste and possibly other food-related stimuli.
Neuropeptide Y-related Peptides and Feeding: Evidence for Multiple Receptor Interactions in the Hindbrain. E. S. CORP and G. P. SMITH. Bourne Laboratory, Cornell University Medical College, White Plains, NY 10605, U.S.A. To determine the specific neuropeptide Y (NPY) receptor involved in the orexigenic effects of NPY, we compared the potency and efficacy with which NPY-related peptides elicit food intake following fourth ventricular administration. The peptides tested include: NPY [YI, Y2 and Y3 receptor activity]; peptide YY (PYY) [YI and Y2 activity]; [Leu 3~, Pro34]NpY (LPNPY) [Y1 and Y3 selective]; NPYI3 36 [Y2 selective]; and NPY2-36 [Y2>>Y1]. Based on halfmaximal and maximal response, PYY was the most potent peptide tested. At low doses, NPY2-36 was as potent as PYY, and more potent than NPY. At higher doses, however, NPY2-36 showed a reduced efficacy (50% of the maximal elicited by PYY) that was apparent across a broad range of doses tested. The YI selective agonist, LP-NPY was less potent and 50% less efficacious than PYY. The Y2 selective agonist, NPYI3_36 was the weakest agonist tested. Potency and efficacy data support the hypothesis that two NPY receptor subtypes are implicated in the stimulation of feeding induced by NPY-related peptides acting in the hindbrain. (Supported by The Whitehall Foundation).
The Effects of Sucrose and Aspartame on Hunger, Taste Preferences and Energy Intakes in Lean and Obese Women. A. DREWNOWSKI, J. LOUIS-SYLVESTRE, C. MASSIEN, J. FRICKER, D. CHAPELOT and M. APFELBAUM. Human Nutrition Program, University of Michigan School of Public Health, Ann Arbor, U.S.A. and INSERM U286, Nutrition Humaine, Faculte de Medecine X. Bichat, Paris, France. The effects of four breakfast preloads on motivational ratings, taste preferences, and energy intakes were examined in 12 lean and 12 massively obese but non-dieting women. The breakfasts, consumed at 0930 hrs consisted of 400 g of sweetened creamy white cheese ("fromage blanc"). Two high-calorie breakfasts (700 kcal) contained either sucrose or maltodextrin with aspartame, while low calorie ones (300 kcal) were aspartame-sweetened or plain. The study followed a within-subject design, with subjects serving as their own controls. Taste preferences for sugar/fat stimuli were measured both before and 2.5 h after breakfast. Hunger ratings were measured every 30 min. The subjects were served three buffet-style meals: lunch (1230 hrs), snack (1600 hrs) and dinner (1900 hrs), always composed of the same 21 foods. As expected, consumption of 300 kcal as opposed to 700 kcal led to more elevated hunger ratings later on, and the consumption of more calories at lunch. However, daily energy intakes exclusive of breakfast (lean women: 1484 kcal; obese women: 2596 kcal) were the same for all four preloads. No caloric compensation was observed by the end of the day: women who consumed 300kcal breakfasts had lower caloric intakes that day. There was no evidence that intense sweeteners promote hunger or result in increased energy intakes in lean or in obese women.
Prediction of Basal Energy Expenditure from Organ Weights in the Rat. P. C. EVEN, A. PELE and S. NICOLAIDIS. Laboratoire de Neurobiologie, CNRS URA 1860, Coll~ge de France, 11 PI. Berthelot 75005 Paris. The problem of matching energy expenditure to body mass, or to its various correlates, always prevented the creation of a predictive equation reliable enough to reveal subtle changes that