Chang GQ, Karatayev O, Ahsan R, Gaysinskaya V, Marwil Z, Leibowitz SF.

The Rockefeller University, 1230 York Ave., New York, NY 10021, USA.

The opioid peptides enkephalin (ENK) and dynorphin (DYN), when injected into the hypothalamus, are known to stimulate feeding behavior and preferentially increase the ingestion of a high-fat diet. Studies of another peptide, galanin (GAL), with similar effects on feeding demonstrate that a high-fat diet, in turn, can stimulate the expression of this peptide in the hypothalamus. The present study tested different diets and variable periods of high- vs. low-fat diet consumption to determine whether the opioid peptides respond in a similar manner as GAL. In six experiments, the effects of dietary fat on ENK and DYN were examined in three hypothalamic areas: the paraventricular nucleus (PVN), perifornical hypothalamus (PFH), and arcuate nucleus (ARC). The results demonstrated that the ingestion of a high-fat diet increases gene expression and peptide levels of both ENK and DYN in the hypothalamus. The strongest and most consistent effect is seen in the PVN. In this nucleus, ENK and DYN are increased by 50-100% after 1 wk, 1 day, 60 min, and even 15 min of high-fat diet consumption. While showing some effect in the PFH, these peptides in the ARC are considerably less responsive, exhibiting no change in response to the briefer periods of diet intake. This effect of dietary fat on PVN opioids can be observed with diets equal in caloric density and palatability and without a change in caloric intake, body weight, fat pad weight, or levels of insulin or leptin. The data reveal a strong and consistent association between these peptides and a rise in circulating levels of triglycerides, supporting a role for these lipids in the fat-induced stimulation of opioid peptides in the PVN, similar to GAL.

Publication Types:

• Comparative Study
• Research Support, N.I.H., Extramural

PMID: 17283367 [PubMed – indexed for MEDLINE]

Vardi M, Nini A.

Carmel Medical Center, Internal Medicine, 7 Michal St, Haifa, Haifa, Israel, 34362. mvardi@013.net.il

BACKGROUND: Erectile dysfunction is a common multi-factorial complication of diabetes mellitus. Numerous strategies have been tried to overcome this diabetic complication. In recent years, phosphodiesterase type 5 (PDE-5) inhibitors have been introduced in the management of erectile dysfunction. OBJECTIVES: The objective of this review was to assess the effect of PDE-5 inhibitors on the management of erectile dysfunction in diabetic men. SEARCH STRATEGY: Studies were obtained from computerised searches of MEDLINE, EMBASE and The Cochrane Library. SELECTION CRITERIA: Randomised controlled trials, in which treatment with PDE-5 inhibitors was compared to control, in diabetic patients with erectile dysfunction. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed trial quality. MAIN RESULTS: Eight randomised controlled trials were identified. A total 976 men were allocated to receive a PDE-5 inhibitor and 741 were randomised to the control groups. Overall, 80% of the participants suffered from type 2 diabetes mellitus. The weighted mean difference (WMD) for the International Index of Erectile Function (IIEF) questions 3 and 4 (frequency of penetration during and maintaining erection to completion of intercourse) was 0.9 (95% CI 0.8 to 1.1) and 1.1 (95% CI 1.0 to 1.2) at the end of the study period, in favour of the intervention group. The WMD for the IIEF erectile dysfunction domain at the end of the study period was 6.6 (95% CI 5.2 to 7.9) in favour of the PDE-5 inhibitors arm. The relative risk (RR) for answering “yes” to a global efficacy question ( “did the treatment improve your erections?”) was 3.8 (CI 95% 3.1 to 4.5) in the PDE-5 inhibitors compared with the control arm. The WMD between the percentage of successful attempts in the PDE-5 inhibitors and in the control arm was 26.7 (95% CI 23.1 to 30.3). Mortality was not reported in any of the included trials. Adverse cardiovascular effects were reported in one study. Headache was the most frequent adverse event reported, flushing was the second most common event, with upper respiratory tract complaints and flu like syndromes, dyspepsia, myalgia, abnormal vision and back pain also reported in a descending order of frequency. The overall risk ratio for developing any adverse reaction was 4.8 (CI 95% 3.74 to 6.16) in the PDE-5 inhibitors arm as compared to the control. AUTHORS’ CONCLUSIONS: Sufficient evidence exists that PDE-5 inhibitors form a care that improves erectile dysfunction in diabetic men.

Publication Types:

• Meta-Analysis
• Review

PMID: 17253475 [PubMed – indexed for MEDLINE]