Hormones: A Factor to Consider When Managing Your Diabetes
Most people know that insulin (either from the persons own pancreas or from an insulin injection) is necessary to control blood sugar levels. In fact, in the absence of effective insulin, blood sugar levels can increase even when the individual has not eaten. But, did you know that there are numerous other hormones that also effect the bodys glucose regulating system and influence the storage, production and release of glucose? These hormones are often called counter regulating hormones since they work opposite insulin.
Glucose Homeostasis (or maintaining the status quo)
The non-diabetic individual regulates blood sugar by more than insulin release. Nature has a kind of barometer that monitors the ambient blood sugar level. When blood sugar levels begin to increase, the hormone insulin is released and the blood sugar rise is limited to no more than 40 to 60mg. When the blood sugar level is falling, the body releases a cluster of counteracting hormones to limit the glucose fall to no more than 40 to 60mg. These hormones include adrenalin, cortisol, glucagon, growth hormone, estrogen, thyroid hormone as well as several others. The chemical message that is activated either instructs the liver to release stored glucose or to produce glucose by converting protein and fat. Normally, this system is so precise that the resulting glucose release raises the circulating glucose level by only 40 to 60mg. In diabetes, this system is disrupted. The glucose is released by the liver but in quantities greater than necessary. This glucose enters the blood stream but frequently does not gain entry into the cells. As a result, blood sugar levels increase often quite dramatically.
Over the course of 24 hours, there are a number of hormones that rise and fall like the tides of an ocean. Usually, 2 to 3 hours before waking, the body normally increases the production of several hormones - cortisol and growth hormone to name a few. These hormones have a powerful effect on the liver and insulin sensitivity. They stimulate the system to produce glucose and they antagonize or fight the effectiveness of insulin. The non-diabetic individual compensates by automatically increasing the amount of insulin that is secreted during this time. In the individual with diabetes, this normal response does not occur. A blood sugar level that is higher in the morning than at bedtime might suggest that there was an inadequate amount of available insulin circulating during this hormonal challenge.
Rebound, bounce, Somoygi all represent the phenomenon that occurs in response to a blood sugar level that has fallen excessively. Since glucose is vital for brain functioning, nature has a defense mechanism that attempts to protect they brain from a lack of glucose. The body automatically provides for the release of glucose when there is a real shortage - the glucose level is less than 40 to 60mg/dl. However, the body also reacts to potential shortages of glucose - the blood glucose level is still normal or perhaps even increased but the glucose level has fallen more than 60 to 100mg/dl. Both of these situations can cause the release of the counter regulating hormones that stimulate the liver to increase the amount of sugar it releases to the blood stream. This response can provide enough glucose to raise the blood sugar to greater than 400mg/dl over a period of 2 to 24 hours. In other words, a low or excessively lowered blood sugar level today could raise your blood sugar level tomorrow.
Adrenaline and cortisol are hormones that are released when the body perceives a threat. The threat may be actual an infection, an illness or a injury; or the threat may be potential perhaps due to an argument, or school or job stress. To prepare the body to defend itself, these hormones alter the heart rate, increase the circulation and stimulate the liver to provide the system with an immediate source of glucose. With this increase in glucose release to the blood stream, insulin secretion should also increase to allow the released glucose to gain entry into the cells. In diabetes, however, this increase is compromised and blood glucose levels often rise as a result of stress.
As a child begins to mature, there are a number of hormonal changes that occur. Growth hormone, cortisol, testosterone and estrogen, to name a few, increase dramatically. In most cases, these hormone levels do not increase slowly but rather are characterized by a dramatic increase and considerable hormone fluctuation. These hormonal storms cause more than the fluctuating moods of adolescence, they also cause variable sensitivity to insulin and an increased production of glucose by the liver. It is not uncommon for children with diabetes to require 2 to 3 times more insulin during this period of transition from childhood to adulthood.
Over the course of a month, a woman will secrete differing levels of female hormones. Both estrogen and progesterone have an effect on both the bodys sensitivity to insulin and the amount of glucose released by the liver. Since these hormones are cyclical (at times higher; at times lower), the insulin requirements for a woman may change 2 to 3 times over the course of a month. In fact, it is not uncommon for some insulin requiring women to need a markedly different insulin schedule during ovulation, before their menses and after their menses. The challenge is knowing when the hormone levels are changing and then initiating the necessary insulin changes.
With pregnancy, there are a number of "contra-insulin" hormones that modify the mothers use of both
glucose and proteins . The actions of a hormone produced by the placenta are responsible, in part, for the tendency for increased blood sugar levels in pregnancy. The modest deterioration in glucose levels especially after eating increases the glucose supply to the fetus and placenta. With the growth of the placenta, larger amounts of these contra-insulin factors are synthesized and additional insulin is required. In the normal pregnant woman, blood sugar levels are maintained in the normal range through an increase in the rate and amount of insulin that is released. A woman with overt diabetes cannot respond to the hormonal output and will require additional insulin as pregnancy progresses. Her insulin needs might actually double or triple by the end of the pregnancy.
Menopause reflects the end of a womans reproductive capability. There is a dramatic change in the production of a number of hormones especially estrogen and progesterone. However, hormonal secretion rarely ends abruptly. In fact, there may be several years when there might be considerable hormonal fluctuation. Because these hormones influence both glucose production and insulin sensitivity, blood sugar levels can be unpredictable during this time. The initiation of hormone replacement therapy might help alleviate both the symptoms of menopause as well as help avoid the lability of the glucose control.
So, how do you tell if hormones are the cause of your hyperglycemia? Detailed record keeping is a start. Consider recording more than your blood sugar levels. Keep a log that notes your food, activity, medications as well as your stress levels, menstrual cycle and your general sense of well being. By studying the log for trends, you and your health care provider might be able to identify the impact of the hormones described above. That information will help you to make the necessary alterations in your insulin regime.
Carolyn Robertson, RN, MSN, CS, CDE
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