Blood sugar and Effects on Hormones
Insulin and cAMP
HORMONE SIGNALING AND DISTORTION
Excessive
insulin levels distorts the other hormones as well. Hormones travel in the blood stream and act on our tissues by interacting with receptors on the surface of the cells (although some hormones, such as the steroids and the thyroid hormones, actually penetrate the cell membrane and act directly within the cell). Normally, when hormones bind to their receptors, they activate special molecules on the inside of the cell known as secondary messengers, which then carry the message to the nucleus where it is heard and acted on.
Insulin stimulates the secondary messengers of inositol triphosphate (IP3) and diacyglycerol (DAG). Glucagon, on the other hand, stimulates the secondary messenger of cyclic Adenosine Mono-Phosphate (cAMP). It is made from ATP, the
energy molecule of the body. So, not only are
insulin and glucagon opposite in their basic physiologic actions, they use different secondary messengers. When a cell’s receptors are acted upon by both
insulin and glucagon, the response of the cell depends on which secondary messenger (cAMP or IP3/DAG) is predominating.*
Insulin is one of the few hormones (cortisol being the other major one) which increases with age - most others, such as thyroid
T3 and T4, DHEA, testosterone, estrogen, growth hormone, etc, etc. decrease with age.
cAMP is used as the secondary messenger by many other hormones in the body as well, including calcitonin (which removes calcium from the blood plasma and deposits it into bone), gonadotrophin (which stimulates reproductive activity of the testes or ovaries), lipotrophin (a hormone-like substance that stimulates the transfer of fat from the body to the bloodstream), follicle stimulating hormone (regulates the many aspects of gonadal function in both males and females), thyroid-stimulating hormone (which controls the synthesis and secretion of the thyroid hormones, which in turn, controls the metabolism of the body, and essentially, a large aspect of its physical age), DHEA (dehydroepiandrosterone) which is the most prevalent of the hormones produced by the adrenal glands and circulates in the blood until it is converted as needed into other hormones. Also, DHEA decreases appetite and tends to inhibit the conversion of glucose to fat, and can also significantly improve one's cholesterol profile, raising HDL levels and lowering LDL levels, Luteinizing Hormone (stimulates secretion of sex steroids from the gonads). -(note: having too much DHEA can mean too much of it converts to estrogen, so I don't believe in taking DHEA)
Unfortunately
insulin opposes cyclic AMP production and therefore suppresses the message of all the hormones which use it as their secondary messenger.* It is kind of ironic that
insulin, which increases with age, suppresses the action of so many other hormones which already decrease with age (or perhaps they decrease because of
insulin’s increase). Never-the-less, it is obvious that hyperinsulinemia will tend to distort the overall balance of your hormones, and when you consider the list of hormones which use cAMP (and it’s only a partial list) and how important their functions are, you can see why excess
insulin is such a large factor in aging. And get this: cAMP is needed to activate Glucagon, as well as thyroid stimulating hormone and luteinizing hormone, as well as others. Hyperinsulinemia will tend to damage our entire metabolism, because the harmony of the signals has been distorted, with some hormones (
insulin and cortisol) playing too loud, and many others which have already become quieter, are being muted.
As an added note concerning the stimulus or suppression of hormones: Growth hormone (GH) secretion, is stimulated by an increase in the plasma concentrations of amino acids (digested
protein) and by a decrease in plasma glucose concentration (low glycemic diet). Obesity blunts GH release in response to many stimuli, including GHRH (Growth Hormone-Releasing Hormone) itself. Weight reduction restores normal GH dynamics. Hypoglycemia (low blood sugar) is a potent stimulus for GH release, and an acute rise in blood sugar inhibits GH release. GH stimulates the cellular uptake of amino acids and
protein synthesis. GH stimulates lipolysis in fat cells, and opposes
insulin by opposing glucose uptake.
- note: fyi there is no way to take GH aside from injection, it is too large to pass through the mucous membrane for sublingual (under tongue) application and is destroyed by the stomach when taken as a pill.
All of the above is just another way of saying, there are many many reasons to keep your blood sugar from spiking by eating a diet that produces a low glycemic load on the endocrine system.
06-20-2005, 05:26 PM
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