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The objective of the present study was to identify brain centers, whose activity changes are related to erotic visual stimuli in healthy, heterosexual, middle aged males. Ten heterosexual, right-handed males with normal sexual function were entered into the present study (mean age 52 years, range 46-55). All potential subjects were screened over 1 h interview, and were encouraged to fill out questionnaires including the Brief Male Sexual Function Inventory. All subjects with a history of sexual arousal disorder or erectile dysfunction were excluded. We performed functional brain magnetic resonance imaging (fMRI) in male volunteers when an alternatively combined erotic and nonerotic film was played for 14 min and 9 s. The major areas of activation associated with sexual arousal to visual stimuli were occipitotemporal area, anterior cingulate gyrus, insula, orbitofrontal cortex, caudate nucleus. However, hypothalamus and thalamus were not activated. We suggest that the nonactivation of hypothalamus and thalamus in middle aged males may be responsible for the lesser physiological arousal in response to the erotic visual stimuli.

Enhanced expression of the TGF-beta signaling inhibitor Smad7 may present one of the novel mechanisms of TGF-beta resistance in human gastric carcinomas.

No abstract

OBJECTIVE:To determine whether chronic central administration of ghrelin can block the effects of leptin on food intake, adiposity, and plasma concentrations of metabolic parameters and hormones. DESIGN: Intracerebroventricular (ICV) infusions of leptin (5 mg/day) for 7 days, with or without ghrelin (1.2 mg/day), in rats. Rats administered leptin plus ghrelin were divided into ad lib-fed and food-restricted groups. MEASUREMENT: Body weight and food intake were monitored daily. Following killing on day 8, epididymal fat weight and fasting plasma concentrations of glucose, insulin, leptin, ghrelin, IGF-1, and adiponectin were determined. RESULTS: ICV infusion of leptin decreased food intake by 39% and fat weight by 41%. Leptin decreased plasma concentrations of glucose, insulin, and leptin and increased plasma ghrelin levels. Central coadministration of ghrelin blocked the effects of leptin. Most of the effects of ghrelin were diminished by food restriction but ghrelin effect on adiposity and plasma insulin concentrations remained in food-restricted rats. CONCLUSION: Chronic central administration of ghrelin reversed the effects of leptin, primarily by altering food intake, but ghrelin may have regulatory effects on adiposity and plasma insulin levels independent of feeding effect.