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In spite of their shared decrease of insulin resistance, oleoyl-estrone [OE], and rosiglitazone show diverging effects on body fat mass and distribution. In this study, we studied whether their effects on white adipose tissue [WAT] were due to a shared or synergistic mechanism of action. Combined effects of OE and rosiglitazone 10-day treatment on WAT lipid, cell mass/number, and the expression of key lipid metabolism and regulatory agents were studied using an adult male overweight rat model. OE decreased WAT cell mass and lipids, parameters not changed by rosiglitazone. The effects of OE and--specially--rosiglitazone were more marked in small-cell WAT (i.e., mesenteric and subcutaneous sites) than in larger cell WAT (retroperitoneal and perigonadal). OE decreased the expressions in WAT of lipogenic enzymes, lipoprotein lipase, PPARs, and SREBP1c, effects symmetrically reversed by rosiglitazone. OE showed no effects on hormone-sensitive lipase expression, which was increased by rosiglitazone. OE strongly inhibited WAT lipogenesis, leaving lipolysis unchanged, thus unbalancing (and helping mobilize) WAT lipid stores. Rosiglitazone acted practically only on small-cell WAT sites, where it favored lipogenesis, but also stimulated lipolysis, which resulted in limited changes in lipid stores. Combination of OE and rosiglitazone induced less fat loss than OE alone.

Summary Objective Since oleoyl-estrone (OE) decreases circulating cholesterol in the rat, we analyzed the response to OE treatment of hepatic gene expressions related with cholesterol metabolism. Methods Male overweight rats treated with oral OE (10nmol/g daily) were compared with a pair-fed (PF) group and controls fed ad libitum . Serum parameters and liver lipid and cholesterol contents were measured. Total tissue RNA was used for real-time PCR analysis of the gene expression of enzymes and regulatory factors of liver cholesterol metabolism. Cholesterol-7α-hydroxylase and ABC transporter A1 protein levels were estimated by Western blot. Results Pair-feeding and OE treatment reduced the expression of 3-hydroxy-3-methyl-glutaryl-CoA synthase. OE increased the expression of the LDL receptor. Cholesterol disposal, through bile acids synthesis, was increased in PF and more markedly in OE rats. Gene expressions of the ABC transporter A1 and apolipoproteins A1 and E were increased in OE rats. The expression of liver X receptor was lower in PF than in OE and controls. Conclusion The rapid disappearance of circulating cholesterol elicited by OE is consequence of: (1) decreased mevalonate pathway activity, (2) a higher expression of the LDL-receptor, and (3) the activation of the oxidation of cholesterol to form bile acids as a consequence of the higher cholesterol concentrations found in liver, also affected by energy availability.

Low-dose oral oleoyl-estrone (OE) (i.e. in dairy products) is hydrolysed to estrone, which promotes growth and fat deposition. However, pharmacological doses of OE are absorbed largely intact and elicit fat losses. Thus, in order to find out how the intestine handles OE, esterase activity (at pH 5, 7 or 8) was measured in rat stomach, duodenum, jejunum, ileum, cecum, large intestine, and liver using OE as substrate. There were no sex-related differences. Pure pancreatic cholesterol-ester esterase hydrolysed OE even in the absence of taurocholate. The differences in the pH-related activity distribution pattern and selective inhibition and taurocholate dependence show that, in addition to the luminal (i.e. pancreatic) cholesterol-ester esterase, other esterases hydrolyse OE; these combined activities may be sufficient to rapidly dispose of pharmacological doses of OE. Female rats received a tritium-labeled OE gavage; the luminal and tissue label content were measured up to 24 h. The high retention of label in the stomach suggest that this may be a significant site of absorption. The rapid decrease of label in intestinal lumen (and rat tissues) shortly after the administration, hint at rapid absorption and disposal. In conclusion, the high OE-esterase activity and early absorption of OE are indicative of upper gastro-intestinal tract absorption skipping most of the medium-tract esterases.

The purpose of this study was to determine whether OE treatment affects the expression of genes related to lipid metabolism under two physiological conditions: late pregnancy and mid-lactation, both characterized by lipid mobilization. Samples of periovarian and retroperitoneal adipose tissue from 21-day pregnant or 15-day lactating dams were used. The expression of LPL, FATP1, FABP4, HSL, ACC1, FAS, PEPCK, GLUT4, PDK4, SREBP1c, adiponutrin and leptin, were compared with their expression in virgin rats. In pregnant rats, FABP4, HSL, PEPCK and PDK4 were over expressed in the periovarian site compared to virgin rats, whereas adiponutrin, FAS, GLUT4 and SREBP1c were underexpressed; the retroperitoneal fat depot showed a similar pattern but ACC1 and leptin were also underexpressed. OE treatment caused a generalized decrease in gene expression in both adipose depots. In lactating dams, the gene expression profile at the periovarian depot was similar to that observed in pregnant rats. OE treatment mimicked the trend observed in pregnant rats, although the intensity of the gene expression changes was lower. After OE treatment, the retroperitoneal adipose depot showed a completely different pattern since the values were close to those of virgin rats. These results corroborate that OE effects in adipose tissue, lowering lipids and depressing their metabolism, already described under other physiological situations, can be also found in late pregnancy and lactation.

Oleoyl-estrone (OE) decreases appetite, induces adipose tissue wasting and resets the ponderostat setting, sparing glucose and protein. The β 3 -adrenergic agonists increase energy expenditure and lipolysis. We studied the combination of both treatments to enhance fat mobilization. Overweight male rats received oral OE for 10 days; they were compared with controls and rats receiving a β 3 -adrenergic agonist, CL316,243 (B3A); another group received both OE and B3A. Serum 3-hydroxybutyrate, NEFA, triacylglycerols and glucose showed only slight changes in all groups vs. controls; OE-treated rats showed lower cholesterol. OE decreased food intake and B3A increased energy expenditure. OE rats lost about 15%, B3A 24%, and those receiving both compounds lost 39% of their initial total body energy. In all cases, most of this energy imbalance was accounted for by the loss of body lipid. The combined treatment of OE and B3A reduced food intake, nevertheless maintaining a high energy expenditure. The combination of a β 3 -adrenergic agonist with OE may help compensate the short-lived effects of the agonist and enhance the lipid mobilization action of OE. The eventual combination of both compounds should be explored as a way to obtain faster and more effective ways to treat obesity.

Oral treatment with oleoyl-estrone induces the loss of body fat and improvement of insulin resistance. Since cholesterol levels are deeply affected by oleoyl-estrone, we investigated here whether short-term treatment affected cholesterol turnover and overall metabolite changes. Wistar female rats received a single oral dose of 10 μmol/kg oleoyl-estrone in 0.2 ml of sunflower oil. Groups of animals were killed at timed intervals and blood samples were taken. In a second experiment series, rats had implanted carotid and jugular cannulas and were given a single gavage of oleoyl-estrone. These rats were used for the measurement of the cholesterol turnover rate. Body weight change and food intake: Glucose, total and HDL-cholesterol, triacylglycerols, 3-hydroxybutyrate, nonesterified fatty acids, insulin, HOMA score in the rats of the first series. Cholesterol: Cholesterol pool changes and cholesterol turnover rates in the rats of the second series. OE induced early effects, decreasing food intake, cholesterol and HDL-cholesterol levels, and increasing insulin sensitivity (HOMA score). OE also increased cholesteryl-ester turnover, and decreased circulating total cholesterol, especially esterified cholesterol pools. The role of early changes in insulin sensitivity induced by oral OE cannot explain per se the deep changes in cholesterol handling, essentially a consequence of accelerated lipoprotein turnover. However, the increase in cholesteryl-ester turnover observed with OE treatment may be, at least in part, a consequence of the decrease in insulin resistance. The compounded effect of increased insulin sensitivity and accelerated lipoprotein turnover may help explain the early and marked hypocholesterolaemic effects of OE.

Oleoyl-estrone is a powerful, slimming adipose tissue-derived signal that has biological effects widely opposed to those of its estrone moiety. The present experiment was designed to determine whether oleoyl-estrone effects on body energy are mediated by the estrogen receptor, blocked with the antagonist tamoxifen. Male Wistar rats were given daily oral doses of 10 micromol/kg d of oleoyl-estrone in oil containing 0 or 0.40 mg/kg d of tamoxifen. The data were compared with controls receiving only oil or 50 nmol/kg d of free estrone. After 10 days, the rats were killed, and their body composition and plasma metabolites and hormones were analyzed. Rats receiving estrone increased their body energy and lipid content compared with controls. Both groups of oleoyl-estrone-treated rats lost body weight, energy, and lipid; the losses in the rats receiving tamoxifen alone were less marked than in those receiving oleoyl-estrone. No significant changes in plasma glucose or triacylglycerols were observed. The patterns of change of estrone sulphate, estradiol, and oleoyl-estrone were consistent with a noticeable hydrolysis of oleoyl-estrone. The lack of differences in the fat mass in oleoyl-estrone-treated rats irrespective of the presence of tamoxifen suggested that the estrogenic pathway was not responsible for the slimming effects observed. Thus, it can be concluded that oleoyl-estrone effects are not mediated through its conversion to estrone or estradiol acting through the estrogen receptor. Tamoxifen partly mimicked the slimming effects of oleoyl-estrone; this could be speculatively explained by tamoxifen acting through the oleoyl-estrone signalling pathway.

Spontaneously hypertriacylglycerolemic obese and diabetic inbred IIM Beta rats were treated with oleoyl- estrone for 10 days. Pair-feeding was performed to determine some oleoyl-estrone effects dependent on the caloric restriction it promotes. Twenty-five 200 day-old Beta males receiving a daily gavage of 0.2 ml sunflower oil were divided into the following groups: 1) daily dose of 10 nmol/g oleoyl-estrone; 2) pair-fed; 3) control. The variables measured were: whole body protein, water and lipid; retroperitoneal and epididymal fat depot weights; plasma urea, glucose, insulin, triacylglycerols and cholesterol. Biomass and food intake were assessed daily. Oleoyl-estrone and pair-fed groups expressed similar variations in body composition and significant body weight losses due to reduction in food intake. Oleoyl-estrone and pair-fed treatments significantly reduced retroperitoneal fat depot weights, but not epididymal ones. In oleoyl-estrone and pair-fed groups hyperglycemia decreased and insulinemia lowered significantly. Plasma normal total cholesterolemia and hypertriacylglycerolemia values typical of Beta rats decreased strongly compared to controls, though attaining significantly different values between oleoyl-estrone and pair-fed groups. Plasma total cholesterol appeared as more sensitive to caloric restriction than triacylglycerols through a specific oleoyl-estrone- mediated effect.Ratas endocriadas de la línea IIMBeta con obesidad, hipertriacilglicerolemia y diabetes espontáneas fueron tratadas con oleoil-estrona durante 10 días. Un grupo con restricción alimentaria fue incluido en el estudio a fin de aislar algunos efectos de la oleoil-estrona dependientes de la restricción calórica que ésta promueve. Veinticinco ratas Beta macho de 200 días de edad a los que se suministró 0.2 ml de aceite de girasol por día se dividieron en los siguientes grupos: (1) dosis diaria de 10 nmol/g de oleoil-estrona; (2) restringido; (3) control. Las variables medidas fueron: proteínas corporales totales, agua y lípidos; pesos de los panículos adiposos retroperitoneal y epididimario; urea, glucosa, insulina, colesterol y triacilgliceroles plasmáticos. Los valores de biomasa y de ingesta de alimentos se registraron diariamente. Los grupos tratados con oleoil-estrona y restringido mostraron variaciones similares en composición corporal y disminuciones significativas en peso corporal debidas a reducciones en la ingesta de alimentos. Los tratamientos con oleoil-estrona y restringido disminuyeron significativamente los pesos de los panículos adiposos retroperitoneales, pero no de los epididimarios. En los grupos tratados con oleoil-estrona y restringido la hiperglicemia disminuyó y la insulinemia lo hizo en forma significativa. Los valores de colesterol total plasmático normal y la hipertriacilglicerolemia característicos de las ratas Beta disminuyeron fuertemente comparados con los controles, aunque alcanzaron valores significativamente diferentes entre los grupos tratados con oleoil-estrona y restringido. El colesterol total plasmático aparece como más sensible a la restricción calórica que los triacilgliceroles a través de un efecto específico mediado por la oleoil-estrona.

OBJECTIVE: To measure acyl-estrone levels in the plasma of Zucker obese rats. If these are lower than expected on the basis of their body-fat content, as observed in morbidly obese humans, this might provide a possible link relating obesity and low body estrone levels. We also examined the effect of pharmacological treatment with oral oleoyl-estrone on the accumulation of estrone. DESIGN: Undisturbed Wistar, Goto-Kakizaki and Zucker (lean Fa/?and obese fa/fa) rats were used to determine the relation between circulating acyl-estrone and body lipids, as well as the total body estrone/lipid ratios. One group of Wistar rats was used to measure the effect of oral gavages of oleoyl-estrone (from 0 to 20 μmol/kg/day) for 10 days on the body content of estrone. MEASUREMENTS: Body weight change and food intake. Total estrone intake, estrone accrual and excretion (by difference) in rats receiving oleoyl-estrone. Total body lipid and estrone. Circulating acyl-estrone levels. RESULTS: In lean rats (Wistar, Zucker and Goto-Kakizaki) there was a direct relation between body lipid content and circulating acyl-estrone; this relation was not found in Zucker obese rats. The estrone/lipid mass ratio was in a similar range in lean rats, but obese animals showed much lower values. Wistar rats receiving pharmacological doses of oleoyl-estrone did not accumulate significant amounts of estrone, but excreted almost all the estrone ingested. CONCLUSIONS: The pharmacological administration of acyl-estrone to rats does not result in the accrual of estrone within a wide range of doses, which confirms the safety of this compound. In rats there is a similar relation between the percentage of body lipids and circulating acyl-estrone to that found in humans. Likewise, obese rats showed lower levels of acyl-estrone than expected. The total content of estrone in the bodies of obese rats was also lower than expected from their high lipid content, which suggests that obese rats are deficient in acyl-estrone.

OBJECTIVE: To determine whether the oral administration of oleoyl-estrone has similar mass-decreasing effects on the main different sites of white adipose tissue (WAT). DESIGN: Adult male Zucker lean rats were given a daily oral gavage of oleoyl-estrone (OE, 10 µmol/kg) in 0.2 ml of sunflower oil for 10 days, and were compared with controls receiving only the oil. The mass of the main WAT sites: subcutaneous, epididymal, mesenteric, retroperitoneal, gluteal, perirenal and interscapular, as well as perirenal and interscapular brown adipose tissue (BAT), were dissected and studied. MEASUREMENTS: The tissue weight, DNA, protein, lipid and total cholesterol content, together with the levels of leptin and acyl-estrone in the larger WAT and BAT masses, were measured. RESULTS: The weights of WAT depots were correlated with body weight but those of BAT were not. Cell size was maximal for epididymal and mesenteric and minimal for subcutaneous and retroperitoneal WAT and BAT. Differences were detected in DNA, and in protein and lipid content between distinct WAT sites. OE treatment tended to decrease cell number and cell size in WAT; only small differences in composition were found between WAT locations inside the visceral cavity and those outside. Decreases in lipid content were maximal in mesenteric fat. Leptin and acyl-estrone content were fairly uniform at the different WAT sites, except for high concentrations in gluteal WAT. OE induced a greater decrease in leptin and acyl-estrone than in DNA and lipids; changes in these hormones were fairly parallel in all sites. CONCLUSIONS: In general, the differences in composition between visceral and peripheral subcutaneous WAT and their responses to OE were less marked than the individual differences observed between specific sites, regardless of location. WAT sites are fairly diverse in composition, but their response to OE treatment was uniform. OE decreased the weight of WAT through reduction of both cell numbers and size; but did not change the mass or composition of BAT significantly. The effects of OE are more marked in the hormonal signals (leptin and acyl-estrone) from the tissue than in its composition and mass.

Adult Zucker lean (Fa/?) female rats received a single 250 nmol oral gavage of 3H-labelled oleoylestrone in 0.2 ml of sunflower oil. After one hour, samples of arterial, portal and suprahepatic blood, and lymph were obtained and fractioned to determine the amount of radioactivity present in the form of free estrone, acyl-estrone and hydrophilic estrone esters in the blood of each vessel. Lipoprotein fractions (chylomicra + VLDL, LDL, HDL and lipoprotein-depleted plasma) were also analysed as well as the distribution of absorbed 3H-estrone in the intestine, specific organs and carcass. About one third of the oleoyl-estrone dose recovered was found in the tissues, mainly in the blood, the rest remaining relatively untouched in the intestinal content. High hypothalamic estrone uptake (compared with the rest of the brain) was observed. Data from non-radioactive estrone measurements showed a similar pattern of absorption and tissue distribution to that obtained by 3H-estrone tracking alone. In both cases, most of the estrone present in the intestinal lumen was absorbed as intact oleoyl-estrone, but a significant part was absorbed as free estrone. There is a net transfer of 3H-estrone into portal blood HDL, and part of the 3H-estrone is also loaded into lymph-carried chylomicra. A large share of free estrone is filtered by the liver, but most of the acyl-estrone absorbed passes unaltered. The oral administration of oleoyl-estrone results in significant absorption of the unaltered molecule, which is transferred to lymph-carried chylomicra and also directly to plasma HDLs. It may be inferred that the HDL fraction contains the physiological carrier of oleoyl-estrone in its role of ponderostat signal.

This study was carried out to determine the effect of sex and oral administration of oleoyloestrone on body weight of 12-week-old female and male Zucker obese (fa/fa) rats initially weighing 350‐380 g and 405‐420 g, respectively. The rats were maintained in standard conditions and given a daily oral gavage of 0.2 ml oleoyl-oestrone dissolved in sunflower oil at a dose of 10 mmol/kg/day for 10 days, and their body weight and food intake was monitored. They were then killed, and their carcass composition (water, lipid, protein and total energy), liver lipids and glycogen and plasma chemistry, insulin, free and total oestrone were measured. Oral administration of oleoyl-oestrone via gavage resulted in significant losses of fat, energy and‐ ultimately‐weight. Treatment with oleoyl-oestrone decreased food intake; the energy expenditure was kept close to that of controls at the expense of internal fat stores. Nevertheless, body protein and plasma metabolite homeostasis were preserved. The slimming effects were more marked in males than in females. Treatment increased circulating acyl-oestrone and reduced to normal levels the high insulin observed in controls. Treatment of genetically obese rats with a daily oral gavage of oleoyl-oestrone resulted in the loss of fat reserves with little modification of other metabolic parameters, except for lower plasma glucose and insulin levels. The results suggest that oleoyl-oestrone, in addition to its slimming effects may be effective as an antidiabetic agent in type 2 diabetes.

Background Oleoyl-estrone administration induces the rapid loss of fat preserving body protein. Aim of the study We intended to check whether the fat-shedding effect of oleoyl-estrone arrests growth in young rats, limiting the buildup of protein and fat. Methods Oleoyl-estrone diluted in a powdered hyperlipidic diet (33 μmol/kg) was given for 30 days to 30-day old Zucker lean (Fa/?) rats. Their body weight and food consumption were followed daily; on day 30 of treatment (60-day old rats), whole body composition (lipid, protein) was determined, and plasmaenergy parameters and leptin were measured. Results Oleoyl-estrone-treated rats grew more slowly than controls fed the hyperlipidic diet alone, and on day 60 their lipid content was about half that of controls. Protein content per kg was identical in both groups, but treated rats tended to accumulate less nitrogen and energy because of their smaller size. No changes in plasma glucose, urea, triacylglycerols, or total cholesterol were observed, but oleoyl-estrone-treated rats showed lower circulating leptin than controls. Conclusion Despite limiting the accumulation of lipids, oleoyl-estrone slowed, but did not arrest growth of young rats, nor elicit a loss of fat or protein.

Adult female rats received a constant i.v. infusion of oleoyl‐estrone (3.5 μmol/kg day) in a lipidic suspension for 14 days. On days 0 (no treatment), 3, 6, 10 and 14, as well as on day 14 for controls (receiving only the lipid); the rats were killed and the expression of the β1‐, β2‐ and β3‐adrenoceptor genes, in brown adipose tissue and in subcutaneous and periovaric white adipose tissue, were measured by RNA protection assay, and compared with that of cyclophyllin. The β3‐adrenoceptor was the most expressed in all adipose tissues, whereas β2 was the less expressed in brown adipose tissue. Oleoyl‐estrone significantly, but moderately, increased the expression of β‐adrenoceptors in the three adipose tissues: β1 increased in subcutaneous, β2 and β3 in periovaric and β3 in brown adipose tissue. Oleoyl‐estrone also decreased β3 expression in subcutaneous white adipose tissue. On day 10, adipocytes isolated from periovaric white adipose tissue of oleoyl‐estrone‐treated rats showed higher cAMP response to an isoproterenol challenge than the controls. The mechanism by which oleoyl‐estrone elicits the wasting of fat reserves could be mediated by adrenergic pathways, at least in part.

Homozygous obese db/db (BKS-Lepr(db) and ob/ob (B6-Lep(ob)) mice were treated for 14 days with a continuous infusion of a fat emulsion (controls) or loaded with oleoyl-estrone at doses of 12.5 and 50 nmol/g x d using surgically inserted osmotic minipumps. Treatment with oleoyl-estrone resulted in a marked decrease in body weight in both strains, compared with the unchecked growth of controls. In db/db mice, plasma urea and insulin, as well as liver lipid decreased with treatment. In ob/ob mice, the effect on insulin was more marked, in parallel with higher plasma lipids pointing to increased fat mobilisation. The results suggest that oleoyl-estrone effects on body fat reserves and insulin resistance are not mediated by leptin, since ob/ob mice lack this hormone and in the db/db it is present but cannot induce effects because of defective leptin receptors; in both cases oleoyl-estrone treatment lowers body weight.

Background Estrone is a relatively abundant hormone widely distributed in tissues of animal and plant origin. It is a mild estrogen that induces increases in body weigt in experimental animals. The relative abundance of estrone esters in animal tissues suggests that it may also be found in foods, from which it may alter the mechanisms of body weight control. Aim of the study To measure the total estrone content in food and to determine whether this may affect body weight. Methods In the first part of the study, a method was devised for the measurement of total estrone content in food. This was applied to the analysis of estrone content in a variety of food. Finally, hyperlipidic diets (18.6 MJ/kg) with a total estrone content 0.89 ± 0.21 μmol/kg (control group) and 1.37 ± 0.13 μmol/kg (laced with estrone fatty esters) were given to rats during 15 days, in order to determine the influence of dietary estrone on the body mass. Zucker lean (Fa/?) rats weighting initially 200–215 g were used. The total estrone (essentially as fatty esters) content of food was investigated by combining a dried methanol extraction with saponification and measurement of the free estrone evolved through radioimmunoassay. Result The content of estrone was zero in some vegetables, but significant in fruits, meats, and especially fats, both of plant and animal origin. The application of these analyses to a standard recommended diet for humans may result in intakes of more than 1 μmol of estrone per day, a figure comparable to the estrogen production by women. When rats were exposed to a raised estrone content in a fat-rich diet, they significantly increased their body weights, doubling their rate off growth (1.99 g/day) compared with controls (0.81 g/day), but maintaining their plasma composition and the proportions of lipid, water, and protein in their carcasses. Conclusion The widely distributed estrone esters in food and their relatively high concentrations may result in high free hormone intakes in humans. The continued and massive intake of estrone may enhance tissue deposition and lead to obesity.

Objective The metabolites of steroidal hormones, including sulphate, glucuronide, and fatty acid (FA) ester derivatives, have received little attention, although these steroid derivatives are essential components in the global assessment of steroid metabolism. The study of FA-derivatives could, in obesity, contribute some insights into factors modulating steroid metabolism and their plasma levels. In a recent study we found that, in rats, an oestrone-fatty acid ester (E1-FA) was produced by white adipose tissue and released into lipoproteins in the blood-stream. We have examined whether E1-FA levels correlate with body fat and insulin sensitivity in humans. Subjects A sample of 20 men and 22 women with varying levels of total body fat (mean body mass index (BMI) 29.2 +/- 4.7, range 22.2-35.8 in men; mean BMI 27.6 +/- 6.3, range 16.8-37.9 in women). All participants were healthy. Measurements We measured oestrone fatty acid esters (E1-FA), body fatness, and body fat distribution variables, as well as insulin sensitivity through a frequently sampled intravenous glucose tolerance test. Plasma E1-FA and serum leptin levels were measured by radioimmunoassay. Results E1-FA levels strongly correlated with BMI (r = 0.69, P = 0.001 in men; r = 0.75, P Conclusions Oestrone-fatty acid esters circulate in human blood in proportion to body fat, independently of gender. Plasma oestrone-fatty acid ester levels are associated with insulin sensitivity in men, independently of body fat. These findings may widen our perspective on the regulation of insulin action and control of body weight.

Adult female Zucker lean and obese rats were treated for 14 days with 3.5 nm/kg oleoyl-estrone (OE) in liposomes (Merlin-2) through continuous i.v. injection with osmotic minipumps. Rat wt. and food intake were measured daily. On days 0, 3, 6, 10, and 14, groups of rats were killed and their hypothalamic nuclei [lateral preoptic (LPO), median preoptic (MPO), paraventricular (PVN), ventromedial (VMH), and arcuate (ARC)] were dissected, homogenized, and used for the measurement of corticosterone-releasing hormone (CRH) by radioimmunoassay. The OE treatment decreased food intake by 67.4% in lean and 62.6% in obese rats (means for 14 days). Body wt. decreased steadily in lean and obese rats, the gap between controls and treated rats becoming 11.5% of initial body wt. in the lean and 12.4% in the obese. The levels of CRH in the ARC nucleus were at least 10-fold higher than in the other nuclei. No changes in CRH were observed in any of the nuclei of obese rats, with levels up to day 6 similar to those of lean rats. In the lean rats, the LPO and ARC nuclei showed peaks on day 10, while the MPO showed no changes and the PVN and VMH nuclei showed a progressive increase, to a maximum at the end of the study (day 14). This contrasted with the peak of plasma adrenocorticotropic hormone (ACTH) and corticosterone (day 6 in lean and day 14 in obese rats). There was a definite lack of correlation between the plasma levels of these two hormones and the levels of CRH in the hypothalamic nuclei, and between the latter and the decreases in appetite in the rats. The loss of appetite induced by OE is not necessarily mediated by CRH, because the obese rats show an intense decrease in voluntary food intake but their hypothalamic nuclei CRH levels do not change at all. Hypothalamic nuclei CRH does not, necessarily, mediate the rise in glucocorticoids induced by OE treatment, because this is observed in lean and obese rats, lean rats increases being mismatched with those of hypothalamic CRH. The OE induced changes in hypothalamic CRH require a fully functional leptinergic pathway, because it is not observed in Zucker fa/fa rats lacking a working leptin receptor. This--indirectly--shows that leptin is needed for its synthesis or modulation.

Female Zucker lean and obese rats were treated for 14 days with 3.5 μmol/kg oleoyl-estrone (OE) in liposomes (Merlin-2). After 0, 3, 6, 10, and 14 days of treatment, the rats were killed and hypothalamic nuclei (lateral preoptic, median preoptic, paraventricular, ventromedial and arcuate) were used for neuropeptide Y (NPY) radioimmunoassay. In 14 days, OE decreased food intake by 26% in lean and 38% in obese rats and energy expenditure by 6% in lean and 47% in obese rats; the body weight gap between controls and treated rats becoming −17.8% of initial b.wt. in the lean and −13.6% in the obese rats. Obese rats showed higher NPY levels in all the nuclei than the lean rats. Despite a negative energy balance and decreased food intake, there were practically no changes in NPY with OE treatment. The results indicate that oleoyl-estrone does not act through NPY in its control of either food intake or thermogenesis in lean and genetically obese rats.

Female adult rats were injected in the jugular vein with oleoyl-3H-estrone incorporated into liposomes. The label rapidly disappeared from the blood, being taken up by the tissues, mainly liver, spleen and lung, which filtered most of the label. However, many other tissues, such as the heart, brown adipose tissue, adrenals and visceral fat incorporated significant amounts of oleoyl-estrone. The analysis of the form in which the label remained 10 min after the injection showed that it was hydrolysed in a large proportion even in liver and lungs. However, in most tissues (brain, brown and white - periovaric - adipose tissues and ovaries), intact oleoyl-estrone accounted for less than one quarter of all tissue label, and less than 10% in the case of subcutaneous adipose tissue and uterus. This rapid destruction of oleoyl-estrone is in agreement with the active role of this compound in the control of body weight.

Aunque se ha caracterizado extensamente la eficacia de la administración de la oleoil estrona sobre la pérdida de grasa corporal, todavía no se ha conseguido averiguar su mecanismo de acción. Esta tesis doctoral se ha centrado en el estudio de la acción de la oleoil estrona a nivel periférico, utilizando ratas Wistar macho con sobrepeso (previamente alimentadas con una dieta de cafetería), y en un modelo de restricción energética forzada equivalente (pair fed), con el fin de discernir los efectos específicos de la oleoil estrona sobre vías metabólicas, partición de la energía y regulación hormonal. Los resultados obtenidos indican que la administración de oleoil estrona junto con una restricción energética adicional no potencia su efecto sobre la pérdida de grasa corporal, aunque se induce la movilización de proteína corporal. Por otro lado, tanto la disminución de las reservas de grasa producidas por el tratamiento con oleoil estrona como el perfil de expresión génica relacionado con el metabolismo lipídico en el tejido adiposo, parecen ser consecuencia, en buena parte, de la disminución de la ingesta. El hígado es, probablemente, el tejido que marca las diferencias en el metabolismo energético tras el tratamiento con oleoil estrona. La acción de la oleoil estrona en el hígado da lugar a cambios profundos y casi siempre en sentido contrario al observado en las ratas pair fed. Concretamente, la administración de oleoil estrona, a pesar de la diminución de la ingesta, disminuye la expresión hepática de los genes implicados en la gluconeogénesis, mantiene la de los relacionados con la glucolisis y la lipogénesis e incluso incrementa la expresión de los implicados en la síntesis de triacilgliceroles, de acuerdo con el incremento del factor de transcripción SREBP-1c, lo que diferencia claramente la acción de la oleoil estrona de la simple restricción energética. Estos resultados explican en parte el mantenimiento de la glucemia y el aumento del consumo de triacilgliceroles por parte de los órganos periféricos. Además, el tratamiento con oleoil estrona incrementa en el hígado la expresión hepática de genes y niveles de proteínas que participan en el transporte reverso de colesterol y en su oxidación a ácidos biliares. Estos efectos están de acuerdo con la disminución del colesterol circulante que se observa tras el tratamiento con oleoil estrona. El efecto adelgazante de la administración de la oleoil estrona se ve limitado por el efecto contraregulador de los glucocorticoides. Los resultados obtenidos indican que las ratas tratadas con oleoil estrona aumentan tanto la síntesis de glucocorticoides en las glándulas adrenales como su eliminación en el hígado, lo que modera el incremento de glucocorticoides circulantes, a diferencia del grupo pair fed, sometido a una restricción energética forzada. La hidrólisis de la oleoil estrona libera estrona, un estrógeno débil pero fácilmente activable a estradiol. La sobrecarga de estrona producida tras la administración de la oleoil estrona inhibe su activación de estradiol, lo que limita los efectos estrogénicos, pero a la vez se inhibe la síntesis y la activación de testosterona, con lo que se produce una marcada disminución de la testosterona circulante. En definitiva, el tratamiento con oleoil estrona disminuye la grasa corporal como consecuencia del incremento de la sensación de saciedad, pero a diferencia de una simple restricción energética mantiene la glucemia y la síntesis de lípidos hepáticos, a la vez que limita el incremento de glucocorticoides circulantes, lo que da lugar a la moderación del nivel de estrés de los animales., This thesis has been focused on the study of the action of oleoyl estrone using overweight male Wistar rats, and a model of restricted energy intake (pair fed), in order to discern the specific effects on metabolic pathways of oleoyl estrone. The decrease in fat reserves produced by treatment with oleoyl estrone as suggests by the expression profile of genes associated with lipid metabolism in adipose tissue seems to be due, largely, to the decrease in food intake. The oleoyl estrone treatment results in profound changes in liver metabolism. In spite of decreased food intake, administration of oleoyl estrone decreases the hepatic expression of genes involved in gluconeogenesis, maintaining those of glycolysis and lipogenesis; there are, even, an increase in those of triacylglycerol synthesis. This is in agreement with SREBP-1c increase, a condition which clearly differentiates the action of oleoyl estrone from pair fed energy restriction. These results explain at least partly the maintenance of blood glucose and the increased consumption of triacylglycerols by peripheral organs. Treatment with oleoyl estrone also increases the hepatic expression of genes involved in reverse cholesterol transport and its oxidation to bile acids. These effects are consistent with the marked decrease of circulating cholesterol observed under treatment with oleoyl estrone. Rats treated with oleoyl estrone increase both glucocorticoid synthesis in the adrenal glands and their oxidative inactivation in the liver, thereby moderating the increase in circulating glucocorticoids, unlike the pair fed group, subjected to a non voluntary restriction in energy intake. The estrone overload produced after the administration of the oleoyl estrone inhibits its own activation to estradiol, thereby limiting the overall estrogenic effects. However, this process also inhibits the synthesis and activation of testosterone, resulting in a decrease its circulating levels. In conclusion, treatment with oleoyl estrone decreases body fat due to a higher level of satiety, but unlike pair fed energy restriction, blood glucose and hepatic lipid synthesis are maintained, and the increase of circulating glucocorticoids is limited, lowering the level of stress endured by the rats.

Oleoyl-estrone (OE) is a powerful slimming agent that is also present in plasma and adipose tissue, where it is synthesized. It acts through the formation of a derivative W. OE effects (and W levels) are proportional to the dose. OE reduces food intake but maintains energy expenditure (thermogenesis). The energy gap is fulfilled with adipose tissue fat, sparing body protein and maintaining glycemia (and glycogen) with lower insulin and leptin levels. OE (in fact W) acts through specific receptors, different from those of estrogen. OE increases cholesterol catabolism, reducing hypercholesterolemia in obese rats. The main metabolic effect on adipose tissue is a lowering of lipid synthesis, maintaining unchanged the intracellular lipolytic processes; the imbalance favors the progressive loss of fat, which is largely used by the muscle. OE administration induces additive effects with other antiobesity agents, such as β3-adrenergic agonists, forcing a massive loss of lipid. Corticosteroids, markedly limit OE action by altering the liver control of lipogenesis. OE also inhibits the action of 17β-hydroxysteroid dehydrogenase, decreasing the synthesis of β-estradiol and testosterone. Discontinuous treatment allows for maximal efficacy both in rats and humans. OE has the advantage that the loss of fat is maintained and does not require additional dietary limitations.

Oleoyl-estrone (OE) is a powerful anti-obesity compound that decreases food intake, decreases insulin resistance and circulating cholesterol. OE stimulates a severe loss of body fat by decreasing adipose tissue lipid synthesis and maintaining lipolysis. Therefore, the body economy loses lipid energy because energy expenditure is maintained. This study analyses the discrepancy between OE effects and the distribution of labelled OE in plasma. Estrone radioimmunoassay of organic solvent plasma extracts of rats treated with OE showed the massive presence of acyl-estrone, but saponification did not release estrone, but containing similar unknown compound. Analysis of label distribution in plasma after oral gavages of (3)H-OE showed the presence of a more hydrophilic compound than OE or any estrogen as well as (3)H(2)O, formed from (3)H-OE in the acidic stomach medium. OE was not attached to a specific transporter in plasma. Through serum HPLC analysis we found W, a labelled derivative more hydrophilic than OE or estrone. The results were confirmed using (14)C-OE. HPLC-MS/MS studies showed that plasma OE levels were one order of magnitude lower than those of W. When liver cell cytosols from rats laden with (3)H-OE were incubated with nuclei from untreated rats, the OE-derived label (i.e., Ws) was found attached to nuclear DNA. Neither estradiol nor estrone interfered with its binding. W is a fairly hydrophilic compound of low molecular weight containing the estrone nucleus, but it is not an ester because saponification or esterases do not yield estrone as OE does. It is concluded that OE acts through its conversion to W, its active form; which binds to a nuclear receptor different from that of estrogen. The estimated W serum levels are proportional to the pharmacological OE effects in vivo. We postulate W as a new type of hormone that exerts the full range of in vivo effects thus far attributed to OE. The full identification of W is anticipated to open the way for the development of new OE-like anti-obesity drugs.

Oleoyl-estrone (OE) has been presented as a potential antiobesity therapeutic, but the published series of studies from one laboratory has not yet been independently confirmed, and the exact mechanism of action is unknown. Based on the hypothesis that OE has potential for the treatment of obesity, male and female rats were chronically treated with several doses of OE to evaluate the impact of this compound on energy metabolism. Body weight, body composition, energy balance parameters and the expression of hypothalamic neuropeptides regulating food intake as well as key markers of the reproductive system were examined. OE impressively reduced food consumption and body weight gain in both sexes. Although a major part of the loss in body weight could be explained by decreased fat mass, a substantial loss of lean mass also occurred after OE administration. The loss of weight can be sufficiently explained by the suppression of food consumption, as there were no major changes in energy expenditure, locomotor activity or respiratory quotient. In situ hybridization data showed no significant change in the expression of key neuropeptides and hormone receptors regulating feeding behavior after OE treatment. Cocaine-amphetamine-regulated transcript (CART) mRNA levels were decreased in the arcuate nucleus of OE-treated rats. Hypogonadism and low plasma testosterone levels were found in OE-treated males, whereas females showed substantially increased liver size. The present data suggest that OE decreases food intake and body weight but also appears to cause a significant impact on the hypothalamus-pituitary-reproductive axis.

Objective To substantiate the relation between obesity and oxidative stress and to assess the potential beneficial properties of a grapeseed proanthocyanidin extract (GSPE), the amelioration of obesity with oleoyl-estrone (OE), and the possible combined effect of GSPE and OE on the hepatic and renal antioxidant enzyme system in obesity-induced oxidative stress. Methods Male obese Zucker rats were divided into four groups: GSPE, OE, GSPE + OE, and OC (control). For 30 d they were gavaged with GSPE, OE, GSPE + OE, or sunflower oil as the control vehicle (OC). Lean Zucker rats gavaged with the vehicle comprised the lean control group. Hepatic and renal antioxidant enzymes and oxidative biomarkers were determined at the end of the experimental period. Results Hepatic antioxidant activities were higher in obese rats than in lean ones. All these activities decreased when obese rats were treated with GSPE, whereas only some of these activities decreased with OE and GSPE + OE treatments. In the kidney, few antioxidant enzymes had higher activities in obese than in lean rats, and OE and GSPE + OE were the treatments that inhibited most enzymes studied. Glutathione S-transferase activity was always lower with the exception of the kidney of obese rats and all treatments used increased the low glutathione levels found in obesity. Conclusion GSPE and OE improve oxidative stress in obese Zucker rats. The effect of GSPE + OE is comparable to GSPE for the liver and to OE for the kidney. Thus the effects of GSPE and OE are not additive and are organ dependent.