Steroid hormones and the control of body weight

Differentiation of in vitro transcriptional repression and activation profiles of selective glucocorticoid modulators

The SAR at C-5 of the 10-methoxy-2,2,4-trimethylbenzopyrano[3,4-f]quinoline core leading to identification of (-) anti 1-methylcyclohexen-3-yl as the optimum substituent that imparts minimal GR mediated in vitro transcriptional activation while maintaining full transcriptional repression is described. The in vitro profile of these candidates in human cell assays relevant to the therapeutic window of glucocorticoid modulators is outlined.

Nonsteroidal selective glucocorticoid modulators: the effect of C-10 substitution on receptor selectivity and functional potency of 5-allyl-2,5-dihydro-2,2,4-trimethyl-1H-[1]benzopyrano[3,4-f]quinolines

The preparation and characterization of a series of C-10 substituted 5-allyl-2,5-dihydro-2,2,4-trimethyl-1H-[1]benzopyrano[3,4-f]quinolines as a novel class of selective ligands for the glucocorticoid receptor is described. Substitution at the C-10 position of the tetracyclic core with linear, two-atom appendages (OCH(3), OCF(2)H, NHMe, SMe, CH=CH(2), Ctbd1;CH, CH(2)OH) provided molecules of high affinity (K(i) = 2-8 nM) for the human glucocorticoid receptor (hGR) with limited cross-reactivity with other steroid receptors (PR, MR, AR, ER). Optimal analogues showed slightly less potent but highly efficacious E-selectin repression with reduced levels of GRE activation efficacy in reporter gene assays relative to prednisolone. Preliminary SAR of analogues containing substitution at the C-9 and C-10 positions identified the 9-OH, 10-OMe analogue 50 and the 9-OH, 10-Cl analogue 58 as compounds that demonstrated potent, GR-mediated inhibition in a conconavalin A stimulated T-cell proliferation assay in both rodent and human whole blood monocytes. When evaluated for their in vivo effects in carrageenan-induced paw edema in rats, 50, 58, and 10-OCF(2)H analogue 35 showed dose-dependent anti-inflammatory effects (50, ED(50) = 16 mg/kg; 58, ED(50) = 15 mg/kg; 35, ED(50) = 21 mg/kg vs ED(50) = 15 mg/kg for 18 and ED(50) = 4 mg/kg for prednisolone).

Pharmacological approaches for the treatment of obesity

The high incidence of obesity, its multifactorial nature, the complexity and lack of knowledge of the bodyweight control system, and the scarcity of adequate therapeutics have fuelled anti-obesity drug development during a considerable number of years. Irrespective of the efforts invested by researchers and companies, few products have reached a minimum level of effectiveness, and even fewer are available in medical practice. As a consequence of anti-obesity research, our knowledge of the bodyweight control system increased but, despite this, the pharmacological approaches to the treatment of obesity have not resulted yet in effective drugs. This review provides a panoramic of the multiple different approaches developed to obtain workable drugs. These approaches, however, rely in only four main lines of action: control of energy intake, mainly through modification of appetite;control of energy expenditure, essentially through the increase of thermogenesis;control of the availability of substrates to cells and tissues through hormonal and other metabolic factors controlling the fate of the available energy substrates; andcontrol of fat reserves through modulation of lipogenesis and lipolysis in white adipose tissue. A large proportion of current research is centred on neuropeptidic control of appetite, followed by the development of drugs controlling thermogenic mechanisms and analysis of the factors controlling adipocyte growth and fat storage. The adipocyte is also a fundamental source of metabolic signals, signals that can be intercepted, modulated and used to force the brain to adjust the mass of fat with the physiological means available. The large variety of different approaches used in the search for effective anti-obesity drugs show both the deep involvement of researchers on this field and the large amount of resources devoted to this problem by pharmaceutical companies. Future trends in anti-obesity drug research follow closely the approaches outlined; however, the increasing mass of information on the molecular basis of bodyweight control and obesity will in the end prevail in our search for effective and harmless anti-obesity drugs.

Plasma adrenal, gonadal, and conjugated steroids before and after long-term overfeeding in identical twins

An analysis of the data collected in the Quebec Overfeeding Study of identical twins was undertaken to determine any evidence of a genotype effect on plasma levels of adrenal and gonadal steroids arising from long term positive energy balance. Plasma levels of sex hormone-binding globulin (SHBG), testosterone, dihydrotestosterone (DHT), dehydroepiandrosterone sulfate (DHEA-S), androsterone glucuronide, androstane-3 alpha, 17 beta-diol glucuronide (3 alpha-DIOL-G), and cortisol were measured in 12 pairs of young, sedentary, male monozygotic twins before and after 100 days of overfeeding. The dietary energy excess of 4.2 MJ/day (1000 Cal), 6 days a week, resulted in a total positive energy balance of 353 MJ (84,000 Cal). Overfeeding induced significant changes (P < 0.0001) in body weight and other measures of body composition. Within-twin pair resemblance was observed at baseline in all steroids, except cortisol [intraclass correlation range: DHEA-S, 0.50 (P < 0.05); DHT, 0.77 (P < 0.001)] and was lost with overfeeding, except for DHT and SHBG (P < 0.05). SHBG levels fell and 3 alpha-DIOL-G rose with the gain in body fatness. The change in testosterone was a significant correlate of the change in upper body fat (r = -0.48; P < 0.05). The change in 3 alpha-DIOL-G correlated positively with increases in all measures of central adiposity (r = 0.52; P < 0.01). A decrease in DHEA-S occurred with a higher, but not with a lower, gain in abdominal visceral fat (P < 0.05). Thus, analysis of adrenal and gonadal steroids and of conjugated metabolites before and after overfeeding in monozygous twins supports the idea that there is a genotype effect on steroid circulating steroid levels and that these blood levels are correlated with the pattern of body fat distribution. Moreover, the baseline within-twin pairs similarity in steroid levels was attenuated by prolonged positive energy balance and body fat gain.

Rats receiving the slimming agent oleoyl-estrone in liposomes (Merlin-2) decrease food intake but maintain thermogenesis

Oleoyl-estrone given i.v.--incorporated in liposomes to mimic lipoprotein delivery--(Merlin-2) to normal weight rats, induces a dose-dependent weight loss. Analysis of body composition showed that body protein concentration was preserved and fat stores wasted. The respiratory quotient was consistent with the massive oxidation of body fat, since the diet contained practically no lipid. Appetite was affected by Merlin-2, and thus food intake showed a transient decrease. But oxygen consumption (and basal metabolic rates) was kept practically unchanged at the levels of the controls, i.e. higher than needed to oxidize the food ingested during the weight loss period. Brown adipose tissue uncoupling protein levels were proportionally preserved with a 2-week treatment, but it lost a substantial amount of lipid. In conclusion, Merlin-2 is a slimming agent with considerable potential given its powerful fat-wasting action, since it maintains thermogenesis despite lowered energy intake.

Short-term handling of the slimming agent oleoyl-estrone in liposomes (Merlin-2) by the rat

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.