The Meal Patterns of the Oestrous Cycle and Their Motivational Significance

1974 ◽  
Vol 26 (3) ◽  
pp. 489-494 ◽  
Author(s):  
R. F. Drewett

Food intake was monitored continuously throughout the oestrous cycle of the rat by operant methods. On the night of oestrus the size of meals eaten was reduced and the average intermeal interval was shorter; and even after meals of the same size, oestrous animals returned to eat again more quickly than dioestrous animals. These results suggest that the way in which ovarian oestrogens reduce food intake is by intensifying processes responsible for the short-term satiation of hunger without affecting the motivational processes responsible for its arousal. Signs of motivational arousal at oestrus could thus be the result of a self-imposed nutritional deprivation, rather than a direct effect of ovarian hormones on sexual receptivity.

2012 ◽  
Vol 37 (3) ◽  
pp. 520-529 ◽  
Author(s):  
Shlomi Tamam ◽  
Nick Bellissimo ◽  
Barkha P. Patel ◽  
Scott G. Thomas ◽  
G. Harvey Anderson

The effect of short duration exercise (EXR) on food intake (FI) and energy balance (EB) is not well understood in either normal weight (NW) or overweight (OW) and obese (OB) 9–14 years old children. Our purpose was to describe the effects of activity and a glucose drink on short term FI, appetite, and EB in NW, OW, and OB boys. Each boy received in random order either a noncaloric Sucralose sweetened control or glucose (1.0 g·kg–1 body weight) drink 5 min after either exercise (EXR) or sedentary (SED) activity. Boys exercised for 15 min at their ventilation threshold (VT) in experiment 1 or at 25% above their VT in experiment 2. FI was measured at an ad libitum pizza meal 30 min after drink consumption. FI was lower after the glucose drink (p < 0.001) but not affected by activity, even though EXR increased appetite (p < 0.001). OW/OB boys ate more total food than NW boys (p = 0.020). EB over the duration of the experiments was reduced by EXR in OW/OB boys (p = 0.013) but not in NW boys in either experiment (p > 0.05). We conclude that intake regulation in OW/OB boys in response to a glucose drink is similar to NW boys, but it may be less responsive to activity.


2012 ◽  
Vol 213 (3) ◽  
pp. 277-284 ◽  
Author(s):  
Sara Baldassano ◽  
Anna Lisa Bellanca ◽  
Rosa Serio ◽  
Flavia Mulè

We investigated the potential anorectic action of peripherally administered glucagon-like peptide 2 (GLP2) in lean and diet-induced obese (DIO) mice. Mice, fasted for 16 h, were injected i.p. with native GLP2 or [Gly2]GLP2, stable analog of GLP2, before or after GLP2 (3–33), a GLP2 receptor (GLP2R) antagonist, or exendin (9–39), a GLP1R antagonist. Food intake was measured at intervals 1, 2, 4, 8, and 24 h postinjection. In addition, we tested in lean mice the influence of [Gly2]GLP2 on gastric emptying and the effects of GLP1 alone or in combination with [Gly2]GLP2 on food intake. [Gly2]GLP2 dose dependently and significantly inhibited food intake in lean and DIO mice. The reduction of food intake occurred in the first hour postinjection and it was sustained until 4 h postinjection in lean mice while it was sustained until 2 h postinjection in DIO mice. GLP2 significantly inhibited food intake in both lean and DIO mice but only in the first hour postinjection. The efficiency of [Gly2]GLP2 or GLP2 in suppressing food intake was significantly weaker in DIO mice compared with lean animals. The [Gly2]GLP2 anorectic actions were blocked by the GLP2R antagonist GLP2 (3–33) or by the GLP1R antagonist exendin (9–39). The coadministration of [Gly2]GLP2 and GLP1 did not cause additive effects. [Gly2]GLP2 decreased the gastric emptying rate. Results suggest that GLP2 can reduce food intake in mice in the short term, likely acting at a peripheral level. DIO mice are less sensitive to the anorectic effect of the peptide.


Endocrinology ◽  
2006 ◽  
Vol 147 (12) ◽  
pp. 5940-5947 ◽  
Author(s):  
Y. C. Loraine Tung ◽  
Sarah J. Piper ◽  
Debra Yeung ◽  
Stephen O’Rahilly ◽  
Anthony P. Coll

Functional disruption of either MC3R or MC4R results in obesity, implicating both in the control of energy homeostasis. The ligands for these receptors are derived from the prohormone proopiomelancortin (POMC), which is posttranslationally processed to produce a set of melanocortin peptides with a range of activities at the MC3R and MC4R. The relative importance of each of these peptides α-MSH, γ3-MSH, γ2-MSH, γ-lipotropin (γ-LPH) and, in man but not in rodents, β-MSH] in the maintenance of energy homeostasis is, as yet, unclear. To investigate this further, equimolar amounts (2 nmol) of each peptide were centrally administered to freely feeding, corticosterone-supplemented, Pomc null (Pomc−/−) mice. After a single dose at the onset of the dark cycle, α-MSH had the most potent anorexigenic effect, reducing food intake to 35% of sham-treated animals. β-MSH, γ-LPH, and γ3- and γ2-MSH all reduced food intake but to a lesser degree. The effects of peptide administration over 3 d were also assessed. Only α-MSH significantly reduced body weight, affecting both fat and lean mass. Other peptides had no significant effect on body weight. Pair-feeding of sham-treated mice to those treated with α-MSH resulted in identical changes in total weight, fat and lean mass indicating that the effects of α-MSH were primarily due to reduced food intake rather than increased energy expenditure. Although other melanocortins can reduce food intake in the short-term, only α-MSH can reduce the excess fat and lean mass found in Pomc−/− mice, mediated largely through an effect on food intake.


1995 ◽  
Vol 74 (3) ◽  
pp. 427-436 ◽  
Author(s):  
J. Tomlin

A novel substance called liquid fibre (LF) has been developed which gels in the stomach and dramatically delays gastric emptying. The prolonged stomach distension LF causes would be expected to reduce food intake. The present study tested whether LF affected psychological factors connected with eating behaviour and short-term food intake. Paired studies were carried out on seventeen healthy but overweight volunteers (ten male, seven female) with body mass indices of 24–34 kg/m2 who were non-restricted eaters. On one occasion (randomized) they took drinks of LF (300 ml each) at 09·05, 11·55 and 18·00 hours, and on the other they took placebo drinks. Subjective feelings were assessed by visual analogue scales. The amount of food consumed at an appetizing pre-selected meal presented at 12·15 hours was measured covertly. Food diaries were kept until 16·00 hours on the following day. The visual analogue scales indicated that LF reduced hunger and the amount of food desired, and increased fullness, all of which would be expected to cause a reduction in food intake. However, there were no differences in the amount or type of food eaten at the appetizing test-meal (6073 v. 5824 kJ, P = 0·41). Food eaten later in the day was significantly delayed by LF (7·0 v. 5·9 h, P = 0·030), and the amount tended to be reduced (4328 v. 5439 kJ, P = 0·088). The energy consumed on the following day also tended to be lower after LF (3802 v. 4737 kJ, P = 0·130). This suggests that gastric distension is a relatively unimportant influence on eating behaviour when non-restricted eaters are presented with an appetizing meal and that intestinal factors seem more important for prolonging satiety and reducing subsequent food intake.


2020 ◽  
Vol 134 (4) ◽  
pp. 389-401
Author(s):  
Carla El-Mallah ◽  
Omar Obeid

Abstract Obesity and increased body adiposity have been alarmingly increasing over the past decades and have been linked to a rise in food intake. Many dietary restrictive approaches aiming at reducing weight have resulted in contradictory results. Additionally, some policies to reduce sugar or fat intake were not able to decrease the surge of obesity. This suggests that food intake is controlled by a physiological mechanism and that any behavioural change only leads to a short-term success. Several hypotheses have been postulated, and many of them have been rejected due to some limitations and exceptions. The present review aims at presenting a new theory behind the regulation of energy intake, therefore providing an eye-opening field for energy balance and a potential strategy for obesity management.


1968 ◽  
Vol 59 (3) ◽  
pp. 442-446 ◽  
Author(s):  
G. H. Zeilmaker

ABSTRACT Virgin mice received 2 blastocysts under the kidney capsule. Following an oestrous cycle which occurred 1–4 days after the operation, nearly all the animals became pseudopregnant. It was found that pseudopregnancy induced by ectopic trophoblast could not be terminated by ergocornine administration. In contrast, this drug was effective in interrupting pseudopregnancy induced by sterile mating. The results confirm previous findings a) that placental luteotrophic hormone starts acting soon after blastocyst implantation and b) that ergocornine exerts no direct effect on the ovary.


Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 658
Author(s):  
Erin L. Wood ◽  
David G. Christian ◽  
Mohammed Arafat ◽  
Laura K. McColl ◽  
Colin G. Prosser ◽  
...  

Adjustment of protein content in milk formulations modifies protein and energy levels, ensures amino acid intake and affects satiety. The shift from the natural whey:casein ratio of ~20:80 in animal milk is oftentimes done to reflect the 60:40 ratio of human milk. Studies show that 20:80 versus 60:40 whey:casein milks differently affect glucose metabolism and hormone release; these data parallel animal model findings. It is unknown whether the adjustment from the 20:80 to 60:40 ratio affects appetite and brain processes related to food intake. In this set of studies, we focused on the impact of the 20:80 vs. 60:40 whey:casein content in milk on food intake and feeding-related brain processes in the adult organism. By utilising laboratory mice, we found that the 20:80 whey:casein milk formulation was consumed less avidly and was less preferred than the 60:40 formulation in short-term choice and no-choice feeding paradigms. The relative PCR analyses in the hypothalamus and brain stem revealed that the 20:80 whey:casein milk intake upregulated genes involved in early termination of feeding and in an interplay between reward and satiety, such as melanocortin 3 receptor (MC3R), oxytocin (OXT), proopiomelanocortin (POMC) and glucagon-like peptide-1 receptor (GLP1R). The 20:80 versus 60:40 whey:casein formulation intake differently affected brain neuronal activation (assessed through c-Fos, an immediate-early gene product) in the nucleus of the solitary tract, area postrema, ventromedial hypothalamic nucleus and supraoptic nucleus. We conclude that the shift from the 20:80 to 60:40 whey:casein ratio in milk affects short-term feeding and relevant brain processes.


2011 ◽  
Vol 35 (5) ◽  
pp. 613-628 ◽  
Author(s):  
Erik Gómez-Baggethun ◽  
Manuel Ruiz-Pérez

In the last decade a growing number of environmental scientists have advocated economic valuation of ecosystem services as a pragmatic short-term strategy to communicate the value of biodiversity in a language that reflects dominant political and economic views. This paper revisits the controversy on economic valuation of ecosystem services in the light of two aspects that are often neglected in ongoing debates. First, the role of the particular institutional setup in which environmental policy and governance is currently embedded in shaping valuation outcomes. Second, the broader economic and sociopolitical processes that have governed the expansion of pricing into previously non-marketed areas of the environment. Our analysis suggests that within the institutional setup and broader sociopolitical processes that have become prominent since the late 1980s economic valuation is likely to pave the way for the commodification of ecosystem services with potentially counterproductive effects in the long term for biodiversity conservation and equity of access to ecosystem services benefits.


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