Sterol regulatory element binding protein 1c (SREBP-1c) expression in human obesity.

OBJECTIVE: Investigation of the expression of sterol regulatory element binding protein-1c (SREBP-1c) in different adipose tissue depots in morbidly obese subjects before and after 1 year of weight loss induced by gastric banding operation. RESEARCH METHODS AND PROCEDURES: SREBP-1c expression was studied in 20 massively obese subjects (6 men and 14 women; age: 41 +/- 9 years; weight: 148 +/- 34 kg; percentage of body fat: 42 +/- 4; mean +/- SD) using reverse transcription competitive polymerase chain reaction. Adipose tissue biopsies were taken from omental, subcutaneous abdominal, and femoral depots before weight loss, and from subcutaneous depots after weight loss. Subcutaneous samples were taken also from 6 normal weight subjects. RESULTS: The level of SREBP-1c mRNA was significantly lower in omental (1.8 +/- 0.2 amol/microg of total RNA) than in subcutaneous abdominal (3.7 +/- 0.4 amol/microg of total RNA) or femoral (3.9 +/- 0.4 amol/microg of total RNA; p < 0.001, mean +/- SEM) depots. The values in subcutaneous depots were about twice as high in normal weight (7.4 +/- 2.5 for abdominal and 6.5 +/- 1.5 for femoral, p < 0.01) as in obese subjects. After weight loss, the mRNA levels of SREBP-1c increased in obese subjects, both in subcutaneous abdominal (5.3 +/- 0.7, p < 0.01) and in femoral (4.8 +/- 0.8, p < 0.05) tissue. DISCUSSION: SREBP-1c mRNA expression was lower in omental adipose tissue than in subcutaneous depots in obese subjects before weight loss. Furthermore, the expression of SREBP-1c in obese subjects was clearly lower than in normal weight subjects, but mRNA levels increased along with weight reduction. Weight reduction was associated with increased mRNA levels of SREBP-1c in obese subjects. The reduced expression of SREBP-1c in obesity could be ascribed to lowered action or concentration of insulin, changeable along with weight reduction. However, changes in SREBP-1c expression after weight reduction could also be ascribed to the changes in calorie intake or nutritional habits after gastric banding operation.

Relationship of satisfaction with body size and trying to lose weight in a national survey of overweight and obese women aged 40 and older, United States.

BACKGROUND: Despite the potential benefits of weight loss, the factors associated with weight loss behavior are only beginning to be identified. We examined the association between sociodemographic factors, perceived health, satisfaction with body size, and trying to lose weight. METHODS: Data were obtained from the 1996-1997 U.S. Women's Determinants Study. We included over 1,700 overweight and obese women aged 40 and older from the following four racial/ethnic groups: Hispanic, black, American Indian/Alaskan Native, and non-Hispanic white. RESULTS: About half of the women reported that they were satisfied or very satisfied with their body size. Satisfaction was associated with lower body mass index (BMI), greater age, lower educational level, and better self-rated health. Compared with non-Hispanic white women, women in the other racial/ethnic groups expressed greater body satisfaction. About 65% of women reported that they were currently trying to lose weight. The strongest predictor of trying to lose weight was satisfaction with body size; women who were not satisfied were nine times more likely to report trying to lose weight than those who were very satisfied. Other significant predictors were BMI, race/ethnicity, and age. CONCLUSIONS: Our findings should serve as the impetus for the inclusion of measures of body image in surveillance and intervention studies of weight loss and control. Copyright 2002 American Health Foundation and Elsevier Science (USA)

Weight Loss behaviors and smoking in college students of diverse ethnicity.

OBJECTIVE: To evaluate weight concerns, weight-loss practices (including smoking) in an ethnically diverse group of university students (58% Hispanic). METHODS: Students (n=1,852) completed a survey addressing lifestyle behaviors and weight-control practices. RESULTS: A greater percentage of females than males practiced weight-loss behaviors. More Hispanic and non-Hispanic white students reported dieting, exercising, and using weight loss pills to lose weight. Only 4 of the females reported their primary reason for smoking was to control their weight. CONCLUSION: Gender as well as ethnicity was a dominant factor influencing weight-loss behaviors/concerns of these young adults.

Weight Loss and gender: an examination of physician attitudes.

OBJECTIVE: The purpose of this study was to investigate physician attitudes toward the treatment of overweight and obese individuals and to evaluate potential gender differences in treatment recommendations. RESEARCH METHODS AND PROCEDURES: A survey describing several hypothetical patients was sent to 700 randomly selected physicians; 209 (29.9%) returned the survey. Two versions of the questionnaire (one for men and one for women) described three hypothetical patients at three levels of body mass index (BMI) (32, 28, and 25 kg/m(2)). One-half of the physicians received a version of the questionnaire describing the patients as women, and one-half received a version describing the patients as men. Respondents answered questions about attitudes toward treatment and specific interventions and referrals they would view as appropriate. RESULTS: Physicians were more likely to encourage women with a BMI of 25 kg/m(2) to lose weight than men with the same BMI, and indicated that they would suggest more treatment referrals for women than men. Men with a BMI of 32 kg/m(2) were more likely to be encouraged to lose weight than women with the identical BMI. Physicians were more likely to encourage weight loss and see treatment referrals as appropriate for patients with higher BMIS: DISCUSSION: This study indicates that physicians treat male and female patients differently, with physicians more likely to encourage weight loss and provide referrals for women with a BMI of 25 kg/m(2) than for men with an identical BMI and less likely to encourage weight loss for women than men with a BMI of 32 kg/m(2).

Special Feeding and Care of Senescent Spontaneously Hypertensive Rats.

This study investigated the impact of feeding methods on body weight of senescent female spontaneously hypertensive rats (SHRs) and showed that supplementing powdered feed was useful as they approached heart failure at 22 to 23 months of age. SHRs are genetically predisposed to systemic hypertension and will, with age, progress into complete heart failure resulting in death. Close to the time of heart failure, some rats experienced a loss of appetite and weight loss. It was postulated that either elevated blood pressure, age-associated health issues, or the effort required to access pelleted food prevented the rats from eating properly, resulting in malnutrition and weight loss. As they aged, the rats benefited from the addition of powdered food to ensure that body weights remained stable and to prevent malnutrition that could lead to premature death. Animals were fed commercially available rat chow pellets until they showed persistent signs of weight loss or a lack of interest in their food. At that time, the rats were also given powdered rat chow in shallow bowls to facilitate the eating and the digestion of their food. The rats were weighed weekly to confirm they consumed sufficient calories daily and to ensure that the change to the powdered chow was having the desired effect. Prior to being fed the powdered rat chow, the rats had shown signs of progressive weight loss. After starting the powdered chow, the rats either maintained or gained weight. This study shows that as the female SHR matures, special care and handling is key to maintaining body weights and good health. With only modest changes in routine (i.e., powdered food) and an attentive eye on the rats' daily activities, it was possible to maintain these senescent female SHRs in a healthy condition until the termination of the study or onset of heart failure.

Phenylethanolamine N-methyltransferase G-148A genetic variant and weight loss in obese women.

OBJECTIVE: To understand the impact of the phenylethanolamine N-methyltransferase (PNMT) G-148A gene and nutritional variables on weight loss in obese women. RESEARCH METHODS AND PROCEDURES: One hundred forty-nine women, ages 45 to 65 with a body mass index of >30 kg/m(2), participated in a 6-month, open-label intervention that included Sibutramine ( Meridia ) (15 mg/d) and a monthly health-education class. Anthropometric measurements, vital signs, food frequency, exercise log, medication compliance, and psychological and sociological questionnaires were completed each month. Genetic polymorphisms of PNMT were determined. RESULTS: Univariate analysis of G/G, G/A, and A/A genotypes against tertiles of percentage of weight loss were significant at 3 but not at 6 months (Pearson chi(2): p < 0.006; homozygous/heterozygosity: p < 0.002, p < 0.253, and p < 0.122, respectively). A regression model that included the PNMT genetic variation and certain nutrition and exercise variables demonstrated that only the PNMT gene (beta = 0.360, SE 0.585, and p = 0.003) was statistically significant at 6 months, and the total calories (beta = -0.925, SE = 0.004, and p = 0.009), fiber intake (beta = 0.621, SE = 0.124, and p = 0.000), and PNMT (beta = 0.262, SE = 1.415, and p = 0.024) were significant. DISCUSSION: The homozygosity/heterozygosity of the PNMT gene was highly predictive of significant weight loss with Sibutramine ( Meridia ) during the first 3 months, which highlights the need for specific pharmacotherapy. The early weight-loss success of those subjects who were homozygous for PNMT may have motivated and selected those that would make further dietary changes, which then augmented their final weight loss.

Influence of dexamethasone and weight loss on the regulation of serum leptin levels in obese individuals.

The adipocyte hormone leptin is thought to serve as a signal to the central nervous system reflecting the status of fat stores. Serum leptin levels and adipocyte leptin messenger RNA levels are clearly increased in obesity. Nevertheless, the factors regulating leptin production are not fully understood. The aim of this study was to determine the effects of in vivo administration of the synthetic glucocorticoid dexamethasone and weight loss on serum leptin levels in two independent protocols. Twenty-five obese subjects were studied (18 women and 7 men, mean age 26.6 +/- 6 years, BMI 31.1 +/- 2.5 kg/m(2), %fat 40.3 +/- 8.3) and compared at baseline to 22 healthy individuals. Serum levels of leptin, insulin, proinsulin and glucose were assessed at baseline and after ingestion of dexamethasone, 4 mg per day (2 mg, twice daily) for two consecutive days. To study the effects of weight loss on serum leptin, 17 of the obese subjects were submitted to a low-calorie dietary intervention trial for 8 weeks and again blood samples were collected. Serum leptin levels were significantly higher in the obese group compared to the control group and a high positive correlation between leptinemia and the magnitude of fat mass was found (r = 0.88, P<0.0001). After dexamethasone, there was a significant increase in serum leptin levels (22.9 +/- 12.3 vs 51.4 +/- 23.3 ng/ml, P<0.05). weight loss (86.1 +/- 15.1 vs 80.6 +/- 14.2 kg, P<0.05) led to a reduction in leptin levels (25.13 +/- 12.8 vs 15.9 +/- 9.1 ng/ml, P<0.05). We conclude that serum leptin levels are primordially dependent on fat mass magnitude. Glucocorticoids at supraphysiologic levels are potent secretagogues of leptin in obese subjects and a mild fat mass reduction leads to a disproportionate decrease in serum leptin levels. This suggests that, in addition to the changes in fat mass, complex nutritional and hormonal interactions may also play an important role in the regulation of leptin levels.

Nutritionally induced body weight loss and ovarian quiescence in Shiba goats.

Four female Shiba goats were used to determine the influence of body weight loss by dietary restriction on estrous cyclicity. The dietary restriction was started on the day following ovulation. The goats were fed hay cube and straw at an amount of 30% of energy requirement based on weekly body weight measurement. The ovaries were monitored daily by transrectal ultrasonography and blood samples were collected daily by jugular venipuncture for ovarian steroids analysis. After the start of food restriction, all animals lost body weight and entered ovarian quiescence. Intervals to the onset of ovarian quiescence tended to depend on the body weight of each animal at the start of food restriction. The mean concentration of progesterone during the mid-luteal phase (from 7 to 13 days after ovulation) in the last estrous cycle before ovarian quiescence was significantly lower than that in normal estrous cycle of the control period (19.7 +/- 2.8 vs 12.3 +/- 2.2 ng/ml, P<0.05), whereas there was no significant difference in the length of the luteal phase, determined as the period when corpora lutea existed and concentrations of progesterone were equal to or greater than 1 ng/ml (15.8 +/- 1.5 vs 15.0 +/- 2.8 days, P>0.1). A rise of estradiol concentration and follicular growth in the follicular phase following a decline of progesterone level after luteal regression tended to be suppressed at the onset of ovarian quiescence. It seems that the present results are consistent with previous findings that nutritionally induced body weight loss influences the secretion of ovarian steroids and eventually induces ovarian quiescence.