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Biomedical subjects

Z Glick

Publications and source records attributed to Z Glick.

At least 37 records · Page 2Linked to original sources
PubMed1983

Physiologic responses to exercise in normal and obese women.

The present study examines the possibility that the reduced activity commonly found in obese individuals could stem from a reduced physiological responsiveness to exercise. Responses to bicycle ergometer exercise (300 kpm/min) of four obese and four normal weight women were observed in a metabolic ward. This resulted in decreases in exercise heart rate and oxygen consumption, indicating an improvement in mechanical efficiency and suggesting an increase in physical working capacity. It also resulted in some decreases of resting oral temperature. The differences in the response to exercise between the obese and the normal weight groups were small and not statistically significant. The normal weight subjects showed a trend for greater decreases in heart rate and O2 consumption during exercise, while in the obese resting oral temperature tended to be more reduced. The results suggest that obesity in our subjects was not related to a deranged physiological response to physical activity.

Adolescent↗
PubMed1982

Sodium potassium dependent ATPase in hypophysectomized rats: response to growth hormone, triiodothyronine, and cortisone.

Groups of hypophysectomized rats were treated with pharmacologic doses of growth hormone, triiodothyronine or cortisone acetate alone or with a combination of growth hormone plus triiodothyronine or growth hormone plus cortisone. After a 7 day period of treatment the hydrolysis of ATP in the presence of ouabain (mg ATPase) and in the absence of ouabain (total ATPase) was determined. Ouabain-suppressible sodium, potassium-dependent ATPase or (Na+ + K+) ATPase was calculated as the difference in the rate of hydrolysis in the presence and absence of ouabain. The activity of the Mg ATPase was significantly reduced in brain after treatment with growth hormone regardless of whether other hormone. In liver there was a significant increase in (Na+ + K+) ATPase in growth hormone, triiodothyronine, or (Na+ + K+) ATPase but there was no effect of triiodothyronine or cortisone and no interaction with the effect of growth hormone. In liver there was a significant increase in (Na+ + K+) ATPase in growth hormone, triiodothyronine, or cortisone-treated animals but Mg ATPase was unaffected by hormone treatment except for the group receiving both growth hormone and cortisone. In kidney homogenates both growth hormone and triiodothyronine significantly increased the activity of the (Na+ + K+) ATPase. There was no effect of cortisone. These data suggest that growth hormone and triiodothyronine may both be calorigenic through their effect on the sodium pumping mechanism in the call membrane.

Animals↗
PubMed1982

Opiate receptors, food intake and obesity.

The present studies tested the effect of acute and chronic administration of naloxone on food intake of lean and genetically obese (ob/ob) mice. Acute administration of naloxone, a drug which blocks opiate receptors, produced a greater reduction of food intake in obese (ob/ob) mice than in the lean littermates. For chronic experiments with naloxone, the daily feeding period was shortened to eight hours and two injections of naloxone were given four hours apart. With this procedure of scheduled-feeding the food intake of both lean and obese mice was depressed during the first hour after injecting naloxone. However, beginning on the second day of treatment, the lean mice began to eat more food than the untreated controls during the eight hour feeding period. Food consumption by lean mice reached values 140 to 200% above the control levels between the fourth and sixth day. In the obese mice the rise in food intake was more gradual and did not reach 200% of the control value until the sixth day. Body weight changes reflected the changes in food intake. In contrast to naloxone, chronic treatment with morphine lowered food intake and blocked the stimulatory effect of naloxone. Our findings suggest that endogenous opioids may play a role in signalling satiety and in regulating long-term energy balance.

Animals↗
PubMed1982

Inverse relationship between brown fat thermogenesis and meal size: the thermostatic control of food intake revisited.

This study examines a new hypothesis whereby heat production from brown fat in response to eating may serve as a feedback signal for satiety. To test this hypothesis, in vitro respiration rate of brown adipose tissue (BAT) was determined in relation to the voluntary caloric intake of the preceding test meal. This relationship was examined as a function of meal composition and of obesity. It was found that in rats fed a high fat diet, as well as in two types of obese rats (VMH and Zucker), respiration rate per 100 mg tissue was significantly reduced, and energy intake of the preceding test meal increased compared to rats receiving a low fat diet or to respective lean rats. These data lend support to a brown fat mediated thermostatic hypothesis for the control of food intake.

Adipose Tissue, Brown↗
PubMed1982

Protein synthesis rate in liver and muscle of rats following four days of overfeeding.

Protein synthesis rate in liver and in muscle were determined in control and in 4-day overfed rats. Both the control and the overfed rats received their entire food (liquid diet) by a continuous intragastric infusion through permanently implanted cannulas. Each of the control rats received a daily quantity of the liquid diet which matched its own mean voluntary (ad libitum) intake as determined prior to the experiment. Each of the overfed rats received a daily excess of 35% over its mean daily voluntary intake. Protein synthesis rate was determined using a continuous intravenous infusion of 14C tyrosine. Overfeeding resulted in a 24% reduction (P less than 0.02) in the fractional rate of protein synthesis in the liver, and in a 16% reduction in the muscle. Overfeeding also resulted in a reduction in the ratio of RNA/protein amounting to 11% in the liver (P less than 0.05) and 21% in the muscle (P less than 0.02). These significant reductions ins RNA/protein indicate a relative loss of ribosomes that overnutrition can be associated with a reduced rate of protein synthesis.

Animals↗
PubMed1981

Modes of action of gallic acid in suppressing food intake of rats.

Gallic acid (3,4,5,trihydroxybenzoic acid) is a naturally occurring polyphenol comprising the major hydrolytic product of tannic acid. Gallic acid and tannic acid were previously shown to suppress food intake of animals to a similar extent. However, the mechanism by which this effect takes place has not been previously reported. Reported here is that the effect of gallic acid on food intake is not mediated entirely through taste aversion or through other gastrointestinal factors, since a continuous daily infusion of a gallic acid solution (18 ml; 2%) resulted in a significant reduction of food intake. The catechol moiety of gallic acid plays an important role in its suppression of food intake since administration of tis 4-0 methyl derivative was significantly less effective is suppressing food intake (P less than 0.01). The effectiveness of gallic acid in suppressing food intake diminishes with time, indicating adaptation to the consumption of this polyphenol. Propyl gallate is a more potent suppressor of food intake than gallic acid. Adaptation to the consumption of this polyphenol, it it exists at all, is much slower than with gallic.

Animals↗
PubMed1977

Responses to temperate, cold, and hot environments and the effect of physical training.

Ten young men underwent several tests before and after a training program: a bicycle ergometer test and 60 min of moderate exercise performed at a temperate 24 degrees C; the same work load performed in heat (40.0 degrees C DB, 30.4 degrees C WB) for 3 h; and cold (10 degrees C) exposure for 60 min. Training consisted of 13 1-h sessions of hard, strenuous, and exhaustive work performed in temperate conditions four times a week. Training resulted in substantial decreases in heart rate and rectal temperature responses to exercise in temperate, minor increases in hot, and no significant changes in cold conditions. Subjects who showed good responses to heat, also showed good responses at 24 degrees C, and poor compensatory responses to cold, which were indicated by relatively low heat production and rectal temperature values, and relatively high body heat loss and extremities temperature values. Subjects who showed poor heat tolerance also showed poor responses in temperate and good compensatory responses in cold conditions. Positive correlation coefficients were found between rectal temperatures in the three environments, and between heart rate and sweat rate responses in temperate and hot conditions. The results indicated that moderately severe training causes minor tolerance improvements in heat and no changes in cold, and that responses in temperate, cold, and hot environments are interdependent.

Acclimatization↗
PubMed1976

Weight and skinfold thickness changes during a physical training course.

The effect of an intensive physical training program on body weight and skinfold thickness was compared in subjects who had initially small (group S), medium (group M) and large (group L) skinfold thickness representing mostly thin, normal and obese recruits, respectively. Weight and skinfold thickness at three sites (triceps, subscapula and abdomen) were measured at the beginning and end of a 6 week intensive military training program. Subjects were on an ad-lib diet. Seventy-one percent of the subjects in group S increased their body weight and 60% increased the sum of their skinfold thickness (SSFT) at the three sites during the training period. These increases were significant at P less than 0.001 and P less than 0.01 for weight and SSFT respectively. In groups M and L the trends for changes in SSFT were in the opposite direction, with 68% of the former and 98% of the latter showing decreases in SSFT. The mean decreases were significant at P less than 0.02 and P less than 0.001 for groups M and L respectively. While the subjects in group L lost weight significantly (P less than 0.001), those in group M reduced their weight only slightly. Our data indicate that changes in body fat, indicated by changes in SSFT, during several weeks of physical activity are not unidirectional and are related to the initial skinfold thickness.

Body Composition↗