Saturday, November 6, 2010

Diabetes, Pancreatic Cancer, and Sex Hormones

The pancreas produces vital hormones, but it is also regulated by hormones produced elsewhere in the body. Understanding how those hormones work is a little bit obscure, but vitally important if you have diabetes or cancer.

Several years ago Dr. Guillermo Robles-Diaz and Dr. Andres Duarte-Rojo of the National Institute of Medical Sciences and Nutrition Salvador Zubirán in Mexico City explained the role of sex hormones in pancreatic tissue. Just like many other organs in the body, the pancreas grows in response to sex hormones, but different sex hormones affect different parts of the organ.

1. The insulin-producing beta cells become more active in response to estrogen. Higher estrogen levels are associated with lower rates of diabetes. This fact explains why so many people who develop diabetes often gain weight first--it's actually a self-defense mechanism. Fat cells make estrogen. The more estrogen fat cells make, the more insulin a sick pancreas can make. As hard as it may be to believe, putting on fat doesn't cause diabetes, diabetes causes fat mass, and the common link is insulin. Fortunately, these cells very seldom become cancerous.
2. These same insulin-making cells become less active in response to progesterone. Women's bodies make tremendous amounts of progesterone during pregnancy. The production of progesterone may account for gestational diabetes--which usually goes away after the baby is born. Women who use high-progesterone birth control pills may be at higher risk of type 2 diabetes.
3. When the rest of the pancreas develops cancer (cancer is very rare in the parts of the organ that make insulin), these cancerous parts become very sensitive to testosterone. They work overtime to convert the male sex hormone into its active form.

What's the message to take away from the science? Here are three main possibilities:

1. Men put on belly fat as their bodies try to prevent diabetes. Women also experience this phenomenon, but more after menopause.
2. Any kind of sex hormone replacement or birth control for women that's high in progesterone raises the risk of diabetes, and
3. If you are concerned about preventing or treating pancreatic cancer, use testosterone replacement with extreme caution. More of the injected form actually stays in the system as testosterone. The patches tend to produce estrogen because they are absorbed through the fat that lies beneath the skin.

Selected Reference:

Robles-Diaz G, Duarte-Rojo A. Pancreas: a sex steroid-dependent tissue.
Isr Med Assoc J. 2001 May;3(5):364-8.

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