Changes in nutritional pattern, insulin sensitivity and glucose tolerance during weight loss in obese patients from a Mediterranean area

In order to study the nutritional pattern in obese subjects living in an area with a Mediterranean diet, as well as the modifications in nutritional behaviour, cardiovascular risk factors and insulin sensitivity induced by changes in nutritional pattern, 54 obese patients completed a 20-week behaviour programme. They prospectively fulfilled a food records diary in order to ascertain their nutritional pattern. Weight, body mass index (BMI). waist-to-hip ratio (WHR), blood pressure (BP), cholesterol, HDL-c, LDL-c, triglycerides, fasting and 2 h-post glucose load plasma glucose were determined at the onset and at the end of the study. Insulin sensitivity index (SI), and glucose effectiveness (Sg) were assessed by using the modified FSIVGTT. The usual diet in obese patients living in a Mediterranean country is low in carbohydrates (35%) and high in fats (43%), 55% of the latter being monounsaturated fatty acids (MUFAs), especially olive oil. After the educational programme they decreased the caloric intake to slightly over 700 Kcal/day, with a reduction of 36% in carbohydrates consumption, 18% in proteins and 43% in fats (46% in MUFAs). These modifications resulted in a decrease in weight, BMI, WHR, BP, and fasting and 2 h-post glucose load plasma glucose (all p < 0.05), whereas the lipoprotein profile did not change. In a similar way SI and Kg (glucose disappearance rate) increased, while fasting plasma insulin (FPI) decreased (p < 0.05) and Sg and I1+3 remained unaffected. Our results indicate that weight loss induced by caloric restriction improves insulin sensitivity rather insulin secretory capacity or glucose effectiveness, and all the cardiovascular risk factors but lipoproteic profile, that remains unchanged, probably because of the lower MUFAs consumption. These facts should be taken into account when recommending changes in the diet of obese patients with a Mediterranean-style diet.

Prenatal exposure of rats to antidepressants enhances agonist affinity of brain dopamine receptors and dopamine-mediated behaviour

The effects of acute treatment or prenatal exposure of rats to antidepressants on locomotor activity and [3H]spiroperidol binding to striatal membranes were studied in 25 day old rats. Prenatal exposure or acute treatment with the antidepressants chlorimipramine, iprindole or mianserin reduced locomotor activity on postnatal day 25. On the contrary, prenatal exposure to nomifensine induced locomotor hyperactivity. It was also found that chlorimipramine, iprindole or nomifensine enhanced the locomotor response to apomorphine. Acute treatment with mianserin, markedly decreased locomotion but in utero mianserin did not modify the apomorphine-induced hyperactivity. Scatchard analysis showed no change in the characteristics of binding of [3H]spiroperidol to striatal dopamine receptors after antidepressant treatment. However, the ability of dopamine to compete for these sites was significantly enhanced after prenatal exposure to all the antidepressants. This increase in agonist affinity for dopamine receptors may explain the long-lasting behavioural supersensitivity of dopamine receptors observed after chronic treatment with typical or atypical antidepressants.

Prenatal exposure of rats to antidepressant drugs down-regulates beta-adrenoceptors and 5-HT2 receptors in cerebral cortex. Lack of correlation between 5-HT2 receptors and serotonin-mediated behaviour

Changes in the binding of beta-adrenoceptors and 5-HT2 receptors and in behaviour mediated by serotonin were studied after either acute treatment or prenatal exposure of rats to antidepressant drugs. Chlorimipramine, iprindole and mianserin reduced the density of [3H]dihydroalprenolol-labelled beta-adrenoceptors and of [3H]spiperone-labelled 5-HT2 receptors in 25-day-old rats after prenatal exposure to these drugs from gestational day 6 to delivery. Prenatal exposure to nomifensine reduced also the number of beta-adrenoceptors but, in contrast, the density of 5-HT2 receptors and the KD for binding of [3H]spiperone were markedly increased. Acute treatment of 25-day-old rats with the same antidepressants did not modify in any case the characteristics of binding to beta-adrenergic or 5-HT2 receptors. The behavioural syndrome induced by 5-hydroxytryptophan and clorgyline was only antagonized on acute treatment by mianserin. Chronic treatment in utero with the antidepressants produced varied effects on the serotonin syndrome and there was no correlation between the number of 5-HT2 receptors and the intensity of the behaviour mediated by serotonin. The observed changes in beta-adrenergic and 5-HT2 receptors after prenatal exposure to antidepressant drugs appear to be more marked and longer-lasting than those induced by chronic treatment of adult rats.