scholarly journals The Evolutionarily Conserved Gonadotropin-Releasing Hormone II Modifies Food Intake

Endocrinology ◽  
2004 ◽  
Vol 145 (2) ◽  
pp. 686-691 ◽  
Author(s):  
Alexander S. Kauffman ◽  
Emilie F. Rissman
Keyword(s):  
Food Intake ◽  
Food Restriction ◽  
Similar Function ◽  
Structural Variants ◽  
Short Term ◽  
Primate Brain ◽  
Evolutionarily Conserved ◽  
Ad Libitum ◽  
Ad Libitum Feeding ◽  
Permissive Role

Abstract GnRH is an evolutionarily conserved peptide of which there are multiple structural variants. One form, GnRH II, is the most widespread in vertebrates, but its primary function remains unclear. In female musk shrews, administration of GnRH II, but not GnRH I, reinstates mating behavior previously inhibited by food restriction. Because this finding suggests that the function of GnRH II may be linked to energetic status, we tested whether GnRH II directly affects food intake. Adult female musk shrews were maintained on ad libitum feeding or food restricted for 48 h, after which they were infused centrally with GnRH I (1 μg), GnRH II (1 μg), or saline. Food intake was recorded 90 min, and 3, 6, 24, and 48 h after infusion. GnRH II administration, but not saline or GnRH I, reduced 24-h food intake in ad libitum animals. Short-term food intake (90 min and 3 h) of both ad libitum and underfed shrews receiving GnRH II was also reduced by as much as 33%, relative to the food intake of saline-infused controls. GnRH I infusion did not affect short-term food intake differently than saline infusion in shrews fed ad libitum. In underfed females, GnRH I had an effect on short-term food intake that was intermediate to saline and GnRH II. We conclude that, in addition to its permissive role in regulating reproduction, GnRH II may also modulate food intake in mammals. Because GnRH II is present in primate brain, it may also serve a similar function in humans.

Short-term hormonal responses to food intake in peripubertal female rats

1990 ◽  
Vol 259 (1) ◽  
pp. R25-R31 ◽  
Author(s):  
F. H. Bronson ◽  
P. D. Heideman
Keyword(s):  
Food Intake ◽  
Food Restriction ◽  
Pubertal Development ◽  
Female Rats ◽  
Blood Levels ◽  
Catch Up ◽  
Ad Libitum ◽  
Ad Libitum Feeding ◽  
Circulating Levels ◽  
Stimulating Hormone

These studies focused on the phenomenon of "catch-up" pubertal development. Circulating levels of several hormones were characterized in 8-wk-old female rats whose growth and reproductive development had been blocked before puberty by restricting their food intake. Some of these females were fed ad libitum for 24 h to initiate rapid pubertal development. Blood levels of luteinizing hormone (LH) and growth hormone (GH) were suppressed by food restriction and then partially restored to adult diestrus levels by 24 h of ad libitum feeding. Prolactin titers were also suppressed by food restriction but not significantly elevated by 24 h of ad libitum feeding. Circulating levels of follicle-stimulating hormone (FSH) and thyroid-stimulating hormone (TSH) were unaffected by either treatment. It is concluded that GH could play an active supplementary role to LH in eliciting catch-up pubertal development but that FSH and TSH could play only passive roles at best. The role of prolactin remains uncertain. On a finer time scale, when food-restricted females were examined in relation to the time of day at which they were fed, most showed high-amplitude LH pulses 2-4 h after eating but rarely at any other time. Thus under some conditions LH secretion can be modulated by food intake on an almost hour-by-hour basis. Overall, blood levels of corticosterone were generally but not always inversely correlated with the frequency of LH pulsing in these experiments. Finally, the present results argue against the concept that puberty is dependent on a critical whole body characteristic.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of the subfornical organ on meal-associated drinking in rats

2001 ◽  
Vol 280 (3) ◽  
pp. R669-R677 ◽  
Author(s):  
Elizabeth M. Starbuck ◽  
Douglas A. Fitts
Keyword(s):  
Food Intake ◽  
Hypertonic Saline ◽  
Food Deprivation ◽  
Water Deprivation ◽  
Plasma Osmolality ◽  
Subfornical Organ ◽  
Intragastric Administration ◽  
Drinking Patterns ◽  
Ad Libitum ◽  
Ad Libitum Feeding

A lesion of the subfornical organ (SFO) may disrupt drinking after a meal of dry chow as it does drinking after intragastric administration of hypertonic saline. Food and water intakes of SFO-lesioned (SFOX) and sham-lesioned rats were measured during 90-min tests following various lengths of food deprivation. During the tests, all rats began eating before they began drinking. After 20–24 h of food deprivation, latency to begin drinking after eating had started was longer for SFOX than for sham-lesioned rats. Plasma osmolality was elevated by 2–3% in both lesion groups at 12 min, the latency for sham-lesioned rats to drink, but SFOX rats nevertheless continued eating and delayed drinking. Eating after shorter 4-h food deprivations and ad libitum feeding produced more variable drinking latencies and less consistent effects of SFO lesion. During 24 h of water deprivation, SFO lesion had no effect on the suppression of food intake and did not affect food or water intakes during the first 2 h of subsequent rehydration. These findings indicate that the SFO is involved in initiating water intake during eating and in determining drinking patterns and the amount of water ingested during a meal.

A comparison of the effects of body condition and short-term food restriction on the feeding behaviour of sheep

1996 ◽  
Vol 1996 ◽  
pp. 174-174
Author(s):  
A.M. Sibbald
Keyword(s):  
Food Intake ◽  
Body Condition ◽  
Feeding Behaviour ◽  
Food Restriction ◽  
Term Effect ◽  
Short Term ◽  
Daily Food ◽  
Long Term Effect ◽  
Single Meal

Voluntary food intake is generally inversely related to body condition or fatness in mature sheep (Foot, 1972). Since the intake of pelleted diets by housed sheep consists of a number of discrete feeding bouts or 'meals' (e.g. Bermudez et al., 1989), the relatively long-term effect of body condition on intake will be achieved through changes in feeding behaviour at the level of a single meal. The aim of this experiment was to compare the effects of body condition and short-term food restriction on meal patterns in sheep, to investigate the mechanism by which body condition influences daily food intake.

Brief food restriction increases FA oxidation and glycogen synthesis under insulin-stimulated conditions

2002 ◽  
Vol 282 (4) ◽  
pp. R1210-R1218 ◽  
Author(s):  
Michelle Z. Tucker ◽  
Lorraine P. Turcotte
Keyword(s):  
Fatty Acid ◽  
Insulin Sensitivity ◽  
Food Intake ◽  
Glucose Uptake ◽  
Food Restriction ◽  
Glycogen Synthesis ◽  
Palmitate Uptake ◽  
Ad Libitum ◽  
Muscle Triglyceride ◽  
White Gastrocnemius

To determine the effects of brief food restriction on fatty acid (FA) metabolism, hindlimbs of F344/BN rats fed either ad libitum (AL) or food restricted (FR) to 60% of baseline food intake for 28 days were perfused under hyperglycemic-hyperinsulinemic conditions (20 mM glucose, 1 mM palmitate, 1,000 μU/ml insulin, [3-3H]glucose, and [1-14C]palmitate). Basal glucose and insulin levels were significantly lower ( P < 0.05) in FR vs. AL rats. Palmitate uptake (34.3 ± 2.7 vs. 24.5 ± 3.1 nmol/g/min) and oxidation (3.8 ± 0.2 vs. 2.7 ± 0.3 nmol · g−1 · min−1) were significantly higher ( P < 0.05) in FR vs. AL rats, respectively. Glucose uptake was increased in FR rats and was accompanied by significant increases in red and white gastrocnemius glycogen synthesis, indicating an improvement in insulin sensitivity. Although muscle triglyceride (TG) levels were not significantly different between groups, glucose uptake and total preperfusion TG concentration were negatively correlated ( r 2 = 0.27, P < 0.05). In conclusion, our results show that under hyperglycemic-hyperinsulinemic conditions, brief FR resulted in an increase in FA oxidative disposal that may contribute to the improvement in insulin sensitivity.

scholarly journals Effects of White Potato Preparation on Subjective Appetite, Food Intake and Glycemic Response in Healthy Older Adults (P08-083-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Jennifer Lee ◽  
Robena Amalraj ◽  
Neil Brett ◽  
Sarah Proteau ◽  
Alexander Schwartz ◽  
...  
Keyword(s):  
Older Adults ◽  
Food Intake ◽  
Glycemic Response ◽  
Short Term ◽  
White Potato ◽  
Healthy Older Adults ◽  
Meal Skipping ◽  
Treatment Conditions ◽  
Ad Libitum ◽  
All Treatment

Abstract Objectives Although some epidemiological studies have linked potato consumption to obesity, diabetes, and mortality, there are limited studies on the effects of potatoes on appetite, food intake, and glycemic regulation in older adults. Therefore, the objective was to compare the effects of white potato preparation on subjective appetite, short-term food intake, and glycemic response in healthy older adults (>65 y). Methods Using a within-subject, repeated-measures design, 20 participants (age: 70.5 ± 0.7 y; BMI: 24.2 ± 0.6 kg/m2) completed five treatment conditions. Following an overnight fast, participants completed five treatment conditions (∼283 kcal) of baked potatoes, mashed potatoes, fried French fries, white bread, or continued to fast. Treatment meals were matched for available carbohydrates (33.1 g) and total fat (13.7 g). Subjective appetite and glycemic response were measured at baseline and over 120 min post-meal consumption using visual analogue scales and capillary blood samples, respectively. An ad libitum pizza lunch was provided to measure food intake at 120 min. Results Change from baseline subjective appetite and subjective appetite incremental area under the curve (iAUC) were lower after all treatment meals compared with meal skipping (P < 0.01). Ad libitum pizza lunch food intake was lower after all treatment meals compared with meal skipping by 175–215 kcal (P < 0.02). However, cumulative food intake (treatment meal + ad libitum food intake) did not differ among test conditions (P = 0.26). Change from baseline blood glucose and blood glucose iAUC were higher after all treatment meals compared with meal skipping (P < 0.001), but did not differ from each other. Conclusions White potatoes suppressed subjective appetite and short-term food intake compared with meal skipping, suggesting that white potatoes do not bypass regulatory control mechanisms of energy intake in healthy older adults. Funding Sources Alliance for Potato Research & Education.

The food intake and growth of Australian feral cross Angora kids when fed whole grain barley-lupins diets with three levels of roughage intake

1984 ◽  
Vol 24 (124) ◽  
pp. 77 ◽  
Author(s):  
BA McGregor
Keyword(s):  
Food Intake ◽  
Crude Protein ◽  
Dry Matter ◽  
Barley Grain ◽  
Whole Grain ◽  
Total Food Intake ◽  
Total Food ◽  
Ad Libitum ◽  
Ad Libitum Feeding ◽  
Basal Ration

Kids six months old and of mean liveweight 22 kg were offered a basal ration of barley and lupins (crude protein 15 .4%) supplemented with three levels of chopped hay (0, 13% of total intake and ad libitum). Supplementation of the basal ration with 13% hay increased total dry matter intake from 479 to 753 g/d (P< 0.001) and liveweight gain from 10 to 54 g/d (P<0 .01). Non-significant increases in total food intake and liveweight gains were achieved by supplementing with ad libitum hay; kids fed ad libitum hay actually consumed 26.9% of their diet as hay. They were then offered various mixtures of barley, oats and lupins with 13% chopped hay at near ad libitum feeding. Differences in intake or growth were not significant at P= 0.05 with kids growing at 74, 65 and 101 g/d for those fed barley, oats and lupins respectively. Results indicate that highest food intake was obtained when 13% chopped hay was added to whole barley grain rations.

The effect of housing and food restriction during winter on growth of male red deer calves

1997 ◽  
Vol 64 (1) ◽  
pp. 171-176 ◽  
Author(s):  
J. R. Webster ◽  
I. D. Corson ◽  
J. M. Suttie
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Energy Expenditure ◽  
Food Restriction ◽  
Red Deer ◽  
Management Practice ◽  
Live Weight ◽  
Normal Growth ◽  
Cold Weather ◽  
Ad Libitum

AbstractLow winter growth is a characteristic of male red deer and is caused, in part by a combination of reduced appetite and higher energy expenditure due to cold weather. This study aimed to determine whether housing during winter would reduce energy expenditure and increase the growth rate of male red deer calves. An additional aim was to investigate whether food restriction in winter would be compensated for by increased spring growth. In each of two consecutive years, 80 calves were randomly allocated to eight groups (no. = 10) comprising two replicates of four treatments during winter. Groups were housed inside (I) or outside (O) and given food either ad libitum (AL) or restricted (R) to maintain live weight. Winter treatments (southern hemisphere) ran from 22 May to 25 August (year 1) and from 5 June to 5 September (year 2). During these periods, animals were weighed weekly and group food intake recorded daily. At the end of winter animals were moved outside onto pasture and weighed monthly until the end of spring (27 November, year 1 and 7 December, year 2). In year 2 weighing continued during summer, until 4 April. The animals were slaughtered on 28 November and 18 January (year 1) and 5 April (year 2). The effect of housing on live-weight gain (LWG) and dry-matter intake (DM1) in AL groups was not significant in either year. However in R groups, O had a higher DMI than I in both years (P < 0·05) and a higher LWG than I in year 1 (P < 0·05). LWG was loiver in R than in AL groups in winter in year 1 (P < 0·05) and year 2 (P < 0·001) and live weight was lower in R than in AL groups at the end of winter in both years. Live weight was still lower in R than in AL groups at the end of spring in both years (P < 0·01). In year 2, this live-weight difference was not significant by the end of summer. Hot carcass weight (HCW) was greater in AL animals than R animals (P < 0·05) and dressing proportion was higher in R than in AL (P < 0·05) in year 1. GR (an index of body fatness) was greater (P < 0·05) in O than I in year 1 and was greater (P < 0·05) in AL than in R animals in year 2. Differences in GR between treatments were not significant in either year, with HCW as a covariate.In conclusion, housing calves given food ad libitum during winter did not reduce DMI or increase growth rate. When normal growth rates were prevented by restricting food intake, housing lowered DMI requirement, although such a situation is unlikely to be a useful farm management practice as recovery from the growth check was slow. Annual variations in climate may determine both the food savings made by housing and the extent of compensatory growth of food-restricted animals in spring.

scholarly journals Novel energy-saving strategies to multiple stressors in birds: the ultradian regulation of body temperature

2016 ◽  
Vol 283 (1839) ◽  
pp. 20161551 ◽  
Author(s):  
Glenn J. Tattersall ◽  
Damien Roussel ◽  
Yann Voituron ◽  
Loïc Teulier
Keyword(s):  
Body Temperature ◽  
Multiple Stressors ◽  
Energetic Cost ◽  
Short Term ◽  
Ad Libitum ◽  
Key Sites ◽  
Ad Libitum Feeding ◽  
Reduced Surface ◽  
Internal Body

This study aimed to examine thermoregulatory responses in birds facing two commonly experienced stressors, cold and fasting. Logging devices allowing long-term and precise access to internal body temperature were placed within the gizzards of ducklings acclimated to cold (CA) (5°C) or thermoneutrality (TN) (25°C). The animals were then examined under three equal 4-day periods: ad libitum feeding, fasting and re-feeding. Through the analysis of daily as well as short-term, or ultradian, variations of body temperature, we showed that while ducklings at TN show only a modest decline in daily thermoregulatory parameters when fasted, they exhibit reduced surface temperatures from key sites of vascular heat exchange during fasting. The CA birds, on the other hand, significantly reduced their short-term variations of body temperature while increasing long-term variability when fasting. This phenomenon would allow the CA birds to reduce the energetic cost of body temperature maintenance under fasting. By analysing ultradian regulation of body temperature, we describe a means by which an endotherm appears to lower thermoregulatory costs in response to the combined stressors of cold and fasting.

scholarly journals Gonadotropin-Releasing Hormone-II Messenger Ribonucleic Acid and Protein Content in the Mammalian Brain Are Modulated by Food Intake

Endocrinology ◽  
2006 ◽  
Vol 147 (11) ◽  
pp. 5069-5077 ◽  
Author(s):  
Alexander S. Kauffman ◽  
Karolina Bojkowska ◽  
Aileen Wills ◽  
Emilie F. Rissman
Keyword(s):  
Food Intake ◽  
Food Restriction ◽  
Mammalian Brain ◽  
Mrna Levels ◽  
Female Reproduction ◽  
Messenger Ribonucleic Acid ◽  
Medial Habenula ◽  
Sufficient Energy ◽  
Peptide Family ◽  
Ad Libitum

GnRH-II is the most evolutionarily conserved member of the GnRH peptide family. In mammals, GnRH-II has been shown to regulate reproductive and feeding behaviors. In female musk shrews, GnRH-II treatment increases mating behaviors and decreases food intake. Although GnRH-II-containing neurons are known to reside in the midbrain, the neural sites of GnRH-II action are undetermined, as is the degree to which GnRH-II is regulated by energy availability. To determine whether GnRH-II function is affected by changes in food intake, we analyzed the levels of GnRH-II mRNA in the midbrain and GnRH-II protein in numerous target regions. Adult musk shrews were ad libitum fed, food restricted, or food restricted and refed for varying durations. Compared with ad libitum levels, food restriction decreased, and 90 min of refeeding reinstated, GnRH-II mRNA levels in midbrain and GnRH-II peptide in several target areas including the medial habenula and ventromedial nucleus. Refeeding for 90 min also reinstated female sexual behavior in underfed shrews. In male shrews, abundant GnRH-II peptide was present in all sites assayed, including the preoptic area, a region with only low GnRH-II in females. In contrast to females, food restriction did not affect GnRH-II protein in male brains or inhibit their mating behavior. Our results further define the relationship between GnRH-II, energy balance, and reproduction, and suggest that food restriction may inhibit female reproduction by reducing GnRH-II output to several brain nuclei. We postulate that this highly conserved neuropeptide functions similarly in other mammals, including humans, to fine-tune reproductive efforts with periods of sufficient energy resources.

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