WEDNESDAY, Aug. 5 (HealthDay News) -- A gut hormone called cholecystokinin (CCK) plays an important role in the control of blood sugar production in the liver, according to Canadian researchers.

"We show for the first time that CCK from the gut activates receptors to regulate glucose levels. It does so via a gut-brain-liver neuronal axis," Tony Lam of the University of Toronto said in a news release.

CCK binds to local receptors on nerves of the small intestine, triggering a message to the brain which, in turn, tells the liver to stop producing glucose.

Lam and colleagues also found that rats fed a high-fat diet for a few days became resistant to CCK.

They said their findings suggest that CCK resistance, like insulin resistance, may be a major contributor to high blood sugar often seen in people with a high-fat diet. The results also suggest that drugs that target CCK receptors may help fight diabetes.

The study appears in the Aug. 6 issue of the journal Cell Metabolism.

More information

The U.S. Food and Drug Administration has more about diabetes.

WEDNESDAY, Aug. 5 (HealthDay News) -- A protein that carries and activates sex hormones throughout the body may also predict those at high risk of developing type 2 diabetes, a new study finds.

The protein, called sex hormone-binding globulin (SHBG), regulates the levels of testosterone and estrogen in the blood. Researchers suspect it also plays a role in the development of type 2 diabetes.

"Basically, we have identified plasma SHBG as a strong and significant marker for type 2 diabetes development in initially healthy men and women," said lead researcher Dr. Simin Liu, professor and director of the Center for Metabolic Disease Prevention in the School of Public Health at the University of California Los Angeles, David Geffen School of Medicine.

Low levels of SHBG were a significant predictor for the risk of development of type 2 diabetes, the researchers found.

"To our knowledge, there are few biomarkers for type 2 diabetes prediction that have presented both genetic and plasma phenotypic evidence like ours," Liu said.

The report was published in the Aug. 5 online edition of the New England Journal of Medicine.

For the study, Liu's group looked at SHBG levels in 718 postmenopausal women -- 359 with type 2 diabetes and 359 without -- who participated in the Women's Health Study, a large-scale cardiovascular trial begun in 1993. In a separate investigation, they confirmed their findings in a group of 340 men who participated in the Physicians' Health Study II, a similarly large study.

Besides the inverse relationship between levels of SHBG and type 2 diabetes, they identified two genetic variants in the gene coding for SHBG -- one increases type 2 diabetes risk while the other decrease diabetes risk.

"Plasma SHBG appeared to predict type 2 diabetes risk beyond traditional risk factors," Liu said. "In direct comparison, it significantly outperformed some newer risk predictors such as HbA1c (glycated hemoglobin) and C-reactive protein."

The researchers also used genetic data to confirm that SHBG may play a causal role in the development of type 2 diabetes.

"Our findings provide further support of the importance of the sex-hormone biology, an area of diabetic pathogenesis which has been relatively less well-studied," Liu said.

While the exact causal mechanism involved in SHBG levels and type 2 diabetes are unclear, it appears that SHBG is involved in complex chemical interactions that can increase or decrease the risk for the disease, the researchers say.

Until now, classical thinking and teaching in medicine have never focused on the potential causal role of SHBG in the development of disease, Liu noted. "By directly linking SHBG with diabetes risk at both genetic and plasma levels, our data suggest that SHBG may have important biological effects that go beyond simply regulating sex-hormones in the blood," he said.

These findings provide new insights into the mechanisms underlying the relationship between sex-steroid hormone metabolism and type 2 diabetes, Liu said.

About 24 million Americans have diabetes, mostly type 2, and another 57 million have pre-diabetes, according to the U.S. Centers for Disease Control and Prevention.

"If our initial findings are confirmed, it is our hope that someday SHBG would serve as a critical screening tool for diabetes as well as a target for developing treatment and preventive measures," he said.

Dr. Robert Rapaport, chief of the division of pediatric endocrinology and diabetes at Mount Sinai School of Medicine in New York City, said much is still unknown about the precise association between SHBG and type 2 diabetes.

"SHBG is emerging from a role as just a carrier protein to being a player on its own," Rapaport said.

Rapaport noted that SHBG has been linked to obesity. "So you don't know which came first. Are these genes expressed more in the framework of obesity or not? Clearly, obesity is the main risk factor for type 2 diabetes. Whether or not this is an additional risk factor will be interesting to know," he said.

More information

For more information on type 2 diabetes, visit the National Institute of Diabetes and Digestive and Kidney Diseases.

SUNDAY, Aug. 2 (HealthDay News) -- Metformin, one of the most widely used diabetes drugs, may offer patients the added benefit of lowering their odds for pancreatic cancer by 60 percent, a new study shows.

But the study had a downside: Other common treatments, including the use of insulin or insulin-releasing medications such as sulfonylureas, seemed to boost diabetics' risk for the deadly malignancy.

"We have been long interested in the association between diabetes and pancreatic cancer," explained study lead author Donghui Li, a professor in the department of gastrointestinal medical oncology at the University of Texas M.D. Anderson Cancer Center in Houston. "It's a very complicated association because pancreatic cancer can cause diabetes, while on the other hand diabetics have a higher risk for pancreatic cancer. So it's been quite controversial, and the question is: What can we do to reduce this risk?"

"So here we found that if people use metformin they have a 60 percent lower risk for pancreatic cancer than those who have diabetes but never used metformin," Li said. "And that's quite a dramatic effect. And so far it's the only thing that we've seen that can reduce the risk for pancreatic cancer so much."

Li and her colleagues will publish their findings in the August issue of Gastroenterology.

Metformin is an extremely popular oral medication commonly prescribed for patients coping with type 2 diabetes. It goes by its generic name as well as brand names such as Glucophage, Riomet, Fortamet, Glumetza, Obimet, Dianben and Diabex.

Although there are several other treatment options available, the American Diabetes Association recommends metformin as a first-line treatment for type 2 diabetes.

According to the American Cancer Society, about 34,000 people die of pancreatic cancer each year. Even when detected early, the five-year survival from the disease is about 33 percent.

The current finding is based on an analysis of 973 pancreatic cancer patients (259 of whom were diabetic) and 863 non-cancer patients (109 of whom were diabetic), all of whom received care at M.D. Anderson between 2004 and 2008.

The researchers found that diabetics who had ever taken metformin as a treatment for their condition cut their risk for pancreatic cancer by 60 percent, compared to those who had never taken the drug. The risk reduction was particularly apparent among diabetics who had taken metformin for five years or more, they noted.

Being a smoker, overweight or obese, or having glycemic control issues did not appear to impact the protective relationship between metformin and pancreatic cancer risk, Li and her team observed.

On the other hand, the researchers found that diabetic patients who had taken insulin as a treatment were nearly five times more prone to developing pancreatic cancer than patients who had never taken insulin. Similarly, those who took insulin secretagogues (insulin-releasing drugs such as sulfonylureas or glinides) had more than double the risk of pancreatic cancer than those who had not.

"Because the individuals we looked at who used metformin were comparable in most ways with those who did not, we have confidence in terms of the influential role metformin specifically had on reducing pancreatic risk," Li noted. "And because there is already a general recommendation to use this drug, our finding adds even more of an incentive. Because this drug appears to have a tremendous health impact, and because we have so few tools to use to fight against pancreatic cancer at this point," she added.

"Of course our observation needs to be confirmed with further research with other patient pools," she cautioned. "But hopefully while we're doing that we can find some biomarker to identify higher risk for pancreatic cancer in general among diabetics."

For his part, Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society in Atlanta, described the findings as "interesting" and "significant."

"It does need to be looked at in a larger population, as the authors note," he said. "But meanwhile I think there are two things here worth discussing. One is obviously that there seems to be a reduction in pancreatic cancer among metformin users. But the other issue is the suggestion -- which is not a finding, but a suggestion -- that people on insulin actually have an increased risk for pancreatic cancer."

"Now on this second point it has to be said that people on insulin are generally people who are also overweight and obese," Lichtenfeld stressed. "And that in and of itself is a risk factor for pancreatic cancer. So there are a lot of other interactions in there that could possibly explain the findings. And they need to be explored."

More information

There's more on the causes and treatment of diabetes at the American Diabetes Association  .