S U M M A R YThe scavenger receptors CLA-1/SR-BI and CD36 interact with native and modified lipoproteins and with some anionic phospholipids. In addition, CD36 binds/transports long-chain free fatty acids. Recent biochemical evidences indicates that the rabbit CLA-1/ SR-BI receptor can be detected in enterocytes, and previous studies showed the presence of mRNA for both CLA-1/SR-BI and CD36 in some segments of the intestinal tract. These findings prompted us to study their respective localization and distribution from the human stomach to the colorectal segments, using immunohistochemical methods. Their expression in the colorectal carcinoma-derived cell line Caco-2 was analyzed by Northern blotting. In the human intestinal tract, CLA-1/SR-BI was found in the brush-border membrane of enterocytes from the duodenum to the rectum. However, CD36 was found only in the duodenal and jejunal epithelium, whereas enterocytes from other intestinal segments were not stained. In the duodenum and jejunum, CD36 co-localized with CLA-1/SR-BI in the apical membrane of enterocytes. The gastric epithelium was immunonegative for both glycoproteins. We also found that CLA-1/SR-BI mRNA was expressed in Caco-2 cells and that its expression levels increased concomitantly with their differentiation. In contrast, the CD36 transcript was not found in this colon cell line, in agreement with the absence of this protein in colon epithelium. The specific localization of CLA-1/SR-BI and CD36 along the human gastrointestinal tract and their ability to interact with a large variety of lipids strongly support a physiological role for them in absorption of dietary lipids.

OBJECTIVE:To determine the metabolic alterations that lead to the neonatal administration of monosodium glutamate (MSG), which results in arrested growth and obesity. ANIMALS AND DESIGN: Wistar rats were injected 5 times, every other day, with 4 g of MSGakg b.w. or with hyperosmotic saline (controls), within the ®rst 10 days of life, and were studied at the age of 30 days. RESULTS: Body weight was lower, whereas adipocyte lipid content, cell diameter, surface area and volume were higher in MSG rats than in controls. Plasma glucose, insulin, NEFA, glycerol and triglyceride levels, and in vitro production of NEFA by lumbar fat pad pieces incubated under basal conditions or in the presence of epinephrine and epinephrine plus glucose in the media were lower in MSG than in control rats. In the same fat pad pieces, the conversion of 1-14 C-glycerol into fatty acids was always enhanced and its conversion into glyceride glycerol was enhanced when incubations were carried out in the presence of epinephrine or glucose. Both the hormone sensitive lipase activity and mRNA expression were lower in adipose tissue from MSG rats. Besides, the number of insulin receptors, lipid synthesis from U 14 C glucose, 3 H-2-deoxy D-glucose uptake and cellular GLUT4 translocation index were higher in adipocytes from MSG rats than from the controls. CONCLUSION: It is proposed that an enhanced insulin sensitivity in 1 month old MSG rats is responsible for the decreased lipolytic activity and enhanced glucose uptake. In addition, the enhanced lipogenesis and glycerol reutilization seen in their adipose tissue, disturbs the normal balance between fat depots breakdown and accumulation in favor of the latter.

To investigate the factors controlling maternal depot fat accumulation during early pregnancy and net decrease during late pregnancy, the activity and mRNA expression of adipose tissue lipoprotein lipase (LPL) and hormone-sensitive lipase (HSL) were related to several other lipid metabolic parameters. Virgin control rats, pregnant rats (at days 12, 15, 19, and 21), and lactating rats (at days 5 and 10 postpartum) were studied. In adipose lumbar tissue of late pregnant rats, LPL activity decreased to about one-third that of the virgin control animals, with < 10% of initial LPL mRNA expressed as determined by Northern blots. HSL activity increased maximally 1.5-fold with a fourfold increase of HSL expression at days 12-15 of pregnancy and decreased to control levels after parturition. The HSL-to-LPL mRNA and activity ratios were enhanced from days 15 and 19 of pregnancy, respectively, and remained so even during lactation, mainly because of the marked lowering of the LPL values. This enhancement coincided with increments in plasma free fatty acids and glycerol levels indicating an increased depot fat breakdown. These results give no indication of an involvement of LPL and HSL gene expression changes in the accumulation of maternal depot during early pregnancy. In contrast, such changes could be responsible for the net breakdown of this fat depot during late gestation. Thus, during this physiological state, long-term (e.g., transcriptional) regulation of LPL and HSL gene expression could be an important mechanism for the control of adipose tissue mass breakdown during late gestation.

SUMMARYTo study the prevalence of male obesity-secondary hypogonadism (MOSH) in patients with moderate to severe obesity, we performed a prospective prevalence study including 100 male patients with moderate to severe obesity at a university tertiary hospital. Total testosterone (TT) and sex hormone-binding globulin (SHBG) concentrations among others were assayed in all patients. Serumfree testosterone (FT) concentration was calculated from TT and SHBG levels. Semen analysis was conducted in 31 patients. We found a prevalence of 45% (95% CI: 35-55%) when considering decreased TT and/or FT concentrations. Serum concentrations of TT were correlated negatively with glucose (r = À0.328, p < 0.001) and insulin resistance (r = À0.261, p = 0.011). The same occurred with FT and glucose (r = À0.340, p < 0.001) and insulin resistance (r = À0.246, p = 0.016). Sixty-two percent (95% CI: 39-85%) of the patients with seminogram also presented abnormal results in semen analysis. The frequencies of low TT or low FT values were similar in patients with abnormal or normal semen analysis (p = 0.646 and p = 0.346, respectively). Ejaculate volume inversely correlated with BMI (q = À0.400, p = 0.029) and with excess body weight (q = À0.464, p = 0.010). Our data show the prevalence of MOSH in patients with moderate to severe obesity is high. Low circulating testosterone is associated with insulin resistance and low ejaculate volume with higher BMI and excess body weight. Semen analysis must be performed in these patients when considering fertility whether or not presenting low circulating testosterone.