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Biomedical subjects

L L Bellinger

Publications and source records attributed to L L Bellinger.

At least 91 records · Page 5Linked to original sources
PubMed1979

Relative normophagia and organ growth in growth-retarded weanling rats with dorsomedial hypothalamic lesions.

Weanling rats with ventromedial (VMNL) and dorsomedial (DMNL) hypothalamic lesions and sham-operated controls were maintained up to 198 days after operation. Food intake was measured throughout the experiment and organ weights were recorded at various periods of sacrifice. Comparisons were made between controls and VMNL and DMNL rats, respectively. Food intake and organ weights were expressed in absolute terms and relative to body mass and Kleiber's "metabolic size." VMNL rats were always normophagic and showed lower organ weights, regardless of manner of computation. Rats with DMNL, on the other hand, were absolutely hypophagic but relatively normophagic for considerable periods of time when food intake was referred to body mass. A similar relationship obtained for organ weights. The data fit well with previous results and with a hypothesis that holds that DMNL bring about a "resetting" of some central nervous control system that not only allows the rat so operated to subsist on lower substrate levels but also regulates normal growth in relation to body mass.

Adrenal Glands↗
PubMed1979

Mesencephalic lesions in female rats resulting in normophagia and reduced body weight.

The effects of bilateral mescencephalic lesions in the area of the ventral noradrenergic bundle (VNA) were studied in immature and mature female rats. The food intake consumption of the immature lesioned rats did not differ from sham operated controls whether fed a chow or high fat diet. However, after the surgery the body weights of the two groups began to diverge with the immature lesioned rats obtaining a significantly lower body weight. By the end of the study the immature lesioned rats were also significantly shorter than the controls. Both groups showed normal body composition throughout the measurement period. Upon refeeding after a one day fast the immature female rats defended their lower than normal pre-fast body weight. These data are in good agreement with our earlier findings using immature male rats. The mature lesioned animals also showed normal food consumption when fed a chow type diet. However the lesioned animals did show a brief hyperphagia when placed on a high fat diet. Unlike the immature lesioned rats the body weight of these lesioned animals did not differ from their sham operated controls. It is suggested that lesions in the area of the VNA may result in hyperphagia or, in no effects on food intake or body weight as reported by others or normophagia with reduced body weight. Exact lesion placement may be responsible for these divergent findings.

Animals↗
PubMed1979

Somatic and endocrine consequences of electrolytic lesions in the epi and subthalamus of weanling and mature rats.

Weanling rats received lesions in the zona incerta (ZIN). Sham-operated rats served as controls. Two experiments were performed several months apart. The animals were maintained on lab chow and tap water for 30 days and then sacrificed. Ponderal and linear growth, food and water intake, water/food-intake ratio, and pituitary weights were significantly reduced in rats with ZIN lesions. Plasma, growth hormone, insulin, glucose, and body composition were normal, however. Weanling and mature rats received lesions in the medial habenula (HAB). Sham-operated rats served as controls. The experiment lasted 44 days postoperatively. In the weanling Hab-lesioned rats, body weight changes, body composition pituitary, weight, food and water intake, water/food-intake ratio, and plasma insulin were normal. Linear growth was slightly (p < 0.05) reduced. In the mature HAB-lesioned rats, all the above parameters were normal except for water intake, which was slightly (p < 0.05) reduced. The pathways by which the epi- and subthalamus may influence the observed changes--or the lack thereof--are discussed.

Animals↗
PubMed1978

Feeding responses of rats with dorsomedial hypothalamic lesions given ip 2DG or glucose.

The glucoprivation effects of 2-deoxy-D-glucose (2DG) on feeding behavior were studied in rats with bilateral lesions of the dorsomedial hypothalamic nucleus (DMN) and sham-operated controls. The lesioned and sham-operated rats were injected intraperitoneally with 2DG (5% wt/vol) at doses of either 150 mg/kg, 300 mg/kg, or 500 mg/kg, or with saline ("control days"). At all doses significantly more sham-operated rats ate and showed an increased food consumption during the first few hours after 2DG injection when compared to saline control days. However, their 24-h food consumption was normal or less than normal, depending on the dose of 2DG. On the other hand, rats with DMN lesions (DMN-L) did not increase their food consumption during the 4 h after the injection at any of the 2DG doses. In a second experiment DMN-L and sham-operated controls were injected intraperitoneally with glucose (1.36 g/kg body wt or 2.72 g/kg body wt) or saline after an overnight fast. Glucose loads, compared to saline injections, significantly depressed the controls' food consumption only during the first hour of refeeding. On the other hand, glucose injections did not depress food intake of the DMN-L rats. It is suggested that DMN lesions may have either destroyed glucoreceptors in the DMN that monitor glucose or the glucoprivation effects caused by 2DG and/or glucoreceptive pathways that pass through the DMN.

Animals↗
PubMed1977

Failure of hepatic infusion of amino acids and/or glucose to inhibit onset of feeding in the deprived dog.

Nine mongrels dogs were fed for only 1 hour/day for 7-8 days and the time of onset of their eating and hourly intakes were recorded. At the end of this period, the hepatic portal vein was cannulated and the polyethylene cannula was exteriorized. Upon recovery to their preoperative food intake, the dogs were infused after a 23 hour fast over a 4 minute period with an amino acid (AA) mixture (FreAmine II, McGaw Laboratories) equal to 7.2% (37 trials), 14.4% (28 trials), or 21.6% (28 trials) of the dogs' daily AA requirements and presented with food 4 minutes later. In all 93 trials the dogs ate within 30 seconds of presentation of food and their hourly intakes were not significantly different from isotonic saline infusions. Six 23 hour deprived dogs were infused with 21.6% of their AA requirement and then presented with food 11 minutes later. Again, these dogs began eating within 30 seconds of presentation of food. Finally, 4 dogs were infused over a 4 minute period after a 23 hour fast (12 trials) with 7.2% of their daily AA requirements mixed with 6 g of glucose and presented with food 4 minutes later. The dogs began eating within 30 seconds in all 12 trials and their hourly intakes were not significantly depressed. These results question the existence or role of hepatic glucoammonium receptors involved in the control of feeding behavior.

Amino Acids↗
PubMed1977

Effect of diet consistency, taste and calories on food intake of weanling rats with dorsomedial hypothalamic lesions.

Male weanling Sprague-Dawley rats with dorsomedial hypothalamic lesions (DMNL rats) primarily destroying the dorosomedial hypothalamic nuclei (DMN) showed significant hypophagia on lab chow chunks compared to sham-operated controls. When given a choice between lab chow in the form of chunks or powder, both controls and DMNL rats ate similar amounts of lab chow powder while DMNL rats ate less lab chow chunks. Total caloric consumption was the same as on chunks alone. When returned to lab chow chunks as the only source of calories, the pattern and magnitude of intake was again depressed for the DMNL rats. When offered a choice between Ginger Snaps cookies in chunk form versus powder, DMNL rats remained hypophagic in terms of chunk consumption while the intake from powder was similar in both controls and DMNL rats. When offered a choice between chunks of lab chow and Ginger Snaps, DMNL rats were again hypophagic on lab chow chunks, ate the same as the controls of the cookies, and the total caloric intake was of the same magnitude and pattern as observed in previous tests. The data suggest, but do not conclusively show, that DMNL rats are not hypophagic because they have an aversion to chewing hard food and that, when offered a diet similar in hardness to lab chow chunks i.e., hard cookies, will prefer the less tasty but nutritionally complete lab chow. They are apparently capable of choosing a diet for complete nutrition and, as previously reported, can meter calories competently.

Animal Nutritional Physiological Phenomena↗
PubMed1976

Mesencephalic lesions followed by normophagia but decreased body weight.

Twenty mature male Sprague-Dawley rats were lesioned in the area of the ascending ventral noradrenergic bundle in the mesencephalon. Nine sham-operated animals served as controls. Food intake between the lesioned and nonlesioned groups was not significantly different except for the first day post surgery. However, body weight of the lesioned group was significantly below that of the controls when measured 15 days after the operation. The lesioned animals weighed significantly less than the controls throughout the rest of the experiment. They also were hypoactive when compared to the sham-operated rats. Control rats and lesioned rats did not differ significantly in deep rectal temperature. It is suggested that the significant decrease in body weight of the lesioned rats in the presence of normophagia may be caused by alterations in the animal's metabolism.

Adipose Tissue↗
PubMed1976

Mesencephalic lesions resulting in normophagia, reduced weight and altered metabolism.

The effects of bilateral lesions of the ventral noradrenergic bundle (VNA) were studied in male rats. In contrast to data reported by others, hyperphagia and obesity were not observed following VNA lesions. Indeed, except for a depression during the first three postoperative days, food intake (FI) of the VNA lesioned animals (VNAL) was normal. Interestingly, the body weight (BW) of the VNAL was significantly reduced compared to the controls, and a pair feeding study indicated that this depression of BW was not due to their FI. Computation of FI per metabolic size showed that the VNAL actually had a significantly increased FI compared to the controls. After a two day fast the VNAL lost more metabolic size than controls and upon refeeding they defended their pre-fast BW. The VNAL rats showed normal body composition and circulating glucose, insulin and prolactin. They had reduced free fatty acids, triglycerides, growth hormone and body length. The data suggest that the mesencephalon influences BW set point, some metabolites and possibly overall metabolism.

Animals↗
PubMed1976

Failure to demonstrate alterations in gluconeogenesis in growth-retarded weanling rats with dorsomedial hypothalamic lesions.

Bilateral electrolytic lesions were placed in the dorsomedial hypothalamic nuclei (DMN) of weanling male Sprague-Dawley rats. Sham-operated rats served as controls. After 22 days on lab chow and tap water ad libitum, the animals were injected with U-14 C-alanine 0.167 muC/mu moles intraperitoneally (5 muC and 30 mu moles/100 gm body weight) and sacrificed 2 hr later. There was no significant difference, in the incorporation of the label into total lipid, free fatty acids, glycogen, or tissue protein of both liver and diaphragm, between the DMN-lesioned and the sham-operated rats. Similarly, there was no significant difference in the incorporation into plasma glucose or protein. It is concluded that in spite of profound alterations in both ponderal and linear growth and food intake, there is no disruption of normal gluconeogenesis in the weanling rat with DMN lesions.

Alanine↗
PubMed1976

The weanling rat ventromedial syndrome: males get just as fat as females.

Weanling female and male Holtzman rats received bilateral electroytic lesions in the ventromedial hypothalamic nucleus (VMN) at the age of 27 and 26 days, respectively. Sham-operated rats served as controls. The animals were maintained on a synthetic diet (4.2 Cal/g) and tap water ad lib, and body weight, Lee (obesity) Index, tail length and food and water intake were recorded weekly for 6 weeks. The only parameters in which a significant sex difference could be demonstrated were body weight gains and water intake which were greater in the male VMN rats. Female and male VMN rats also utilized food energy for fat deposition, body weight and body length change to the same extent. The data also show that in growing animals, body weight is a poor criterion for the accurate assessment of obesity status and true growth.

Animals↗