Effects of cannabis use on body mass, fasting glucose and lipids during the first 12 months of treatment in schizophrenia spectrum disorders.

While acute cannabis use stimulates appetite, general population studies suggest that chronic use is associated with reduced risk of obesity and other cardiometabolic risk factors. In this study we investigated changes in body mass index (BMI), fasting blood glucose and lipids, and rates of metabolic syndrome risk factors in cannabis users vs. non-users in 109 minimally treated patients with first-episode schizophrenia, schizophreniform or schizo-affective disorder who were treated according to a standardized treatment regime with depot antipsychotic medication over 12 months. Participants underwent repeated urine toxicology tests for cannabis and those testing positive at any time during the study (n = 40), were compared with those who tested negative at all time points (n = 69). There was a significant group*time interaction effect (p = 0.002) with the cannabis negative group showing a greater increase in BMI than the cannabis positive group, after adjusting for age, sex, methamphetamine use and modal dose of antipsychotic. There were no group*time interaction effects for fasting blood glucose or lipids. Post hoc tests indicated significant increases in fasting blood glucose and triglycerides and a decrease in high-density lipoprotein cholesterol for the cannabis negative group, with no significant changes in the cannabis positive group. Rates of metabolic syndrome did not differ significantly between groups, although more cannabis negative patients had elevated waist-circumference at endpoint (p = 0.003). It may be that chronic cannabis use directly suppresses appetite, thereby preventing weight gain in users. However, other indirect effects such as dietary neglect and smoking may be contributory and could explain our findings.

Implications of FPS1 deletion and membrane ergosterol content for glycerol efflux from Saccharomyces cerevisiae.

The deletion of the gene encoding the glycerol facilitator Fps1p was associated with an altered plasma membrane lipid composition in Saccharomyces cerevisiae. The S. cerevisiae fps1delta strain respectively contained 18 and 26% less ergosterol than the wild-type strain, at the whole-cell level and at the plasma membrane level. Other mutants with deficiencies in glycerol metabolism were studied to investigate any possible link between membrane ergosterol content and intracellular glycerol accumulation. In these mutants a modification in intracellular glycerol concentration, or in intra- to extracellular glycerol ratio was accompanied by a reduction in plasma membrane ergosterol content. However, there was no direct correlation between ergosterol content and intracellular glycerol concentration. Lipid composition influences the membrane permeability for solutes during adaptation of yeast cells to osmotic stress. In this study, ergosterol supplementation was shown to partially suppress the hypo-osmotic sensitivity phenotype of the fps1delta strain, leading to more efficient glycerol efflux, and improved survival. The erg-1 disruption mutant, which is unable to synthesise ergosterol, survived and recovered from the hypo-osmotic shock more successfully when the concentration of exogenously supplied ergosterol was increased. The results obtained suggest that a higher ergosterol content facilitates the flux of glycerol across the plasma membrane of S. cerevisiae cells.

The relationship between transport kinetics and glucose uptake by Saccharomyces cerevisiae in aerobic chemostat cultures.

The steady-state residual glucose concentrations in aerobic chemostat cultures of Saccharomyces cerevisiae ATCC 4126, grown in a complex medium, increased sharply in the respiro-fermentative region, suggesting a large increase in the apparent kS value. By contrast, strain CBS 8066 exhibited much lower steady-state residual glucose concentrations in this region. Glucose transport assays were conducted with these strains to determine the relationship between transport kinetics and sugar assimilation. With strain CBS 8066, a high-affinity glucose uptake system was evident up to a dilution rate of 0.41 h(-1), with a low-affinity uptake system and high residual glucose levels only evident at the higher dilution rates. With strain ATCC 4126, the high-affinity uptake system was present up to a dilution rate of about 0.38 h(-1), but a low-affinity uptake system was discerned already from a dilution rate of 0.27 h(-1), which coincided with the sharp increase in the residual glucose concentration. Neither of the above yeast strains had an absolute vitamin requirement for aerobic growth. Nevertheless, in the same medium supplemented with vitamins, no low-affinity uptake system was evident in cells of strain ATCC 4126 even at high dilution rates and the steady-state residual glucose concentration was much lower. The shift in the relative proportions of the high and low-affinity uptake systems of strain ATCC 4126, which might have been mediated by an inositol deficiency through its effect on the cell membrane, may offer an explanation for the unusually high steady-state residual glucose concentrations observed at dilution rates above 52% of the wash-out dilution rate.