Biomedical subjects

A Geloen

Publications and source records attributed to A Geloen.

6 recordsLinked to original sources

PubMed2001

Angiotensinogen-deficient mice exhibit impairment of diet-induced weight gain with alteration in adipose tissue development and increased locomotor activity.

White adipose tissue is known to contain the components of the renin-angiotensin system, which gives rise to angiotensin II from angiotensinogen (AGT). Recent evidence obtained in vitro and ex vivo is in favor of angiotensin II acting as a trophic factor of adipose tissue development. To determine whether AGT plays a role in vivo in this process, comparative studies were performed in AGT-deficient (agt(-/-)) mice and control wild-type mice. The results showed that agt(-/-) mice gain less weight than wild-type mice in response to a chow or high fat diet. Adipose tissue mass from weaning to adulthood appeared altered rather specifically, as both the size and the weight of other organs were almost unchanged. Food intake was similar for both genotypes, suggesting a decreased metabolic efficiency in agt(-/-) mice. Consistent with this hypothesis, cellularity measurement indicated hypotrophy of adipocytes in agt(-/-) mice with a parallel decrease in the fatty acid synthase activity. Moreover, AGT-deficient mice exhibited a significantly increased locomotor activity, whereas metabolic rate and mRNA levels of uncoupling proteins remained similar in both genotypes. Thus, AGT appears to be involved in the regulation of fat mass through a combination of decreased lipogenesis and increased locomotor activity that may be centrally mediated.

Adipose Tissue↗

PubMed2000

Day-night pattern of energy expenditure and body temperature in cachectic tumour-bearing rats.

The implication of an increase in energy expenditure in cancer cachexia, which seems to be related to the type of tumour, remains unclear. We therefore investigated the energy metabolism and body temperature in anorectic and cachectic rats bearing the Yoshida sarcoma (TB), in comparison with pair-fed (PF) and ad-libitum fed (AL) control rats. The resting energy expenditure was higher in the TB than in the two control groups when corrected for the modifications of body composition. However, the total energy expenditure did not differ between the TB and the AL, presumably because of the drop of activity in TB. There was a temporal distribution of differences in energy expenditure with higher energy expenditure in TB than in AL during the diurnal phase and a lack of difference during the nocturnal phase. The TB presented a fever, which was limited to the diurnal period. Moreover, the acrophase of the body temperature rhythm was delayed in the TB. These results highlight the circadian effects of tumour development on the energy metabolism of the host and hint to the possible implication of cytokines.

Adipose Tissue↗

PubMed1991

Effects of high fat diets on hibernation and adipose tissue in Turkish hamsters.

The effects of dietary fat saturation and fat content on hibernation and several properties of white and brown adipose tissue (WAT and BAT, respectively) were investigated in Turkish hamsters (Mesocricetus brandti). Male hamsters were housed in a long photoperiod (LD 16:8) at 23 degrees C and fed one of three diets: (1) chow (6.5% fat per weight), (2) chow + 13.5% vegetable oil (OIL, 20% fat per weight [largely unsaturated fat]) and (3) chow + 13.5% vegetable shortening [(SHORTENING, 20% fat per weight (largely saturated fat)]. Five weeks later body weights had stabilized and the animals were transferred to a short photoperiod (LD 8:16) at 3 degrees C. At the peak of the hibernation season (17 weeks) the animals were sacrificed within 24 h of arousal. Chow-fed hamsters had the greatest percentage of animals hibernating and days found torpid compared with the two fat-fed groups, with no differences found between the latter two groups for these measures. There were no differences between hibernating (HIB) and non-hibernating (NON-HIB) hamsters across or within the diet groups for any of the BAT measures [uncoupling protein content, mitochondrial mass, lipoprotein lipase (LPL) activity, and in vivo lipogenesis], nor were there significant effects of the diet on these measures. CHOW- and OIL-fed HIB hamsters showed decreases in body weight. All HIB groups had decreases in each carcass component, several fat pad weights, testes weight, and food intake. No consistent differences in WAT LPL activity or in vivo lipogenesis were found between HIB and NON-HIB hamsters.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed1989

Hypotensive and peripheral vascular effects in healthy volunteers of repeated oral administration of pinacidil.

The hypotensive and peripheral vascular effects of two different oral formulations of pinacidil were investigated in twelve healthy male volunteers. Arterial blood pressure, heart rate and calf blood flow were measured on Days 1 and 7. The vasodilator activity of both formulations was confirmed by a significant increase in calf blood flow on both days, which was correlated with a significant decrease in diastolic blood pressure. There was no differences between the tablet and the pellet.

Adult↗

PubMed1989

Sleep changes in emperor penguins during fasting.

The proportion and the distribution over 24 h of the different arousal stages characterized in emperor penguins [wakefulness (W), drowsiness (D), slow-wave sleep (SWS), and paradoxical sleep (PS)] were studied under natural ambient conditions in four subjects that were first fed and then deprived of food for 7-18 days. In both fed and fasting states, each arousal stage was distributed through numerous episodes of short duration. The fasting state provoked only a slight increase in D. There was, however, a large increase in SWS, which increased from 37.5 to 55.4%/day, mainly at the expense of W, which fell from 42.7 to 21.9%/day, in close relation to the first two fasting phases when proteins were saved and when most of the energy was derived from lipids. PS proportions were lower during fasting (from 5.7 to 2.4%/day). These changes in the arousal stages in emperor penguins are examined for their implications in sleep mechanisms and energy saving. Their possible consequences, due to the reduced alertness, are also discussed.

Animals↗

PubMed1985

Potentiated muscular thermogenesis in cold-acclimated muscovy duckling.

The capacity for nonshivering thermogenesis (NST) was examined in 26- to 27-day cold-acclimated (CA) muscovy ducklings reared for 21 days at 4 degrees C. Metabolic rate and integrated electromyographic (EMG) muscle activity were measured at ambient temperature ranging from -10 to 28 degrees C. Compared with controls reared at 30 degrees C, CA ducklings were more resistant to cold and had higher peak metabolic rate in extreme cold. Shivering threshold temperature of CA ducklings was 14.2 degrees C lower than lower critical temperature, whereas for controls the two temperatures were similar. Thus CA ducklings exhibited an NST in moderate cold. In addition, at temperatures that produced shivering, EMG activity in CA duckling muscle was lesser than that of controls, even at a higher metabolic rate. Because these ducklings are devoid of brown adipose tissue, these results indicated an increased thermogenic efficiency of muscular activity in CA ducklings.

Acclimatization↗