Ageing and the Endocrine System

The endocrine system is involved in all of the integrative aspects of life, including growth, sex differentiation, metabolism and adaptation to an ever changing environment. This system is connected with your feelings and emotions. Whether you feel energetic, tired, aggressive or passive, is determined by your endocrine system.  

Altogether there are seven endocrine glands. The pituitary gland is situated behind the eyes, the thyroid gland is in the lower neck and the adrenal glands lie on the top of the kidneys. The pancreas, sitting just behind the stomach, not only has a part to play in digestion but also functions as part of the endocrine system in regulating blood sugar levels. Other endocrine glands are the ovaries in women and the testes in men.  

Endocrine glands generally work in conjunction with one another, so that the release of a hormone in one gland will influence the operation of another gland. Hormones released by the endocrine glands are generally thought of as chemical messengers that are transported in the body’s fluids. Of particular interest lately is the human growth hormone. Recent research suggests that somatropin or human growth hormone (GH) is useful as an anti-aging hormone. GH has a pulsatile pattern of release, controlled by the pituitary gland, during various life periods and under diverse clinical circumstances.  

There are several factors such as exercise and levels of fitness, androgen and oestrogen production, sleep, body mass and nutritional status which impact on the production and release of GH and levels certainly decrease with age. The decline in the overall GH level with age is called somatopause. Signs of somatopause in adults are: decrease in lean body mass, decreased joint cartilage, decreased cardiac endurance, decreased rate of wound healing, decreased sleep quality and quantity.

Symptoms can be: fatigue, anxiety, increased social isolation, depression and weight gain. These signs and symptoms can have a significant impact on the quality of a person’s life. GH has profound effects on tissue growth and metabolism. Most of these actions are thought to be mediated through GH dependent production of insulin-like growth factors (IGF) and associated binding proteins. GH apparently stimulates IGF production after binding to specific cell surface receptors in the liver and possibly other tissues.  

As mentioned earlier, there are a number of lifestyle factors that influence GH. These include stress, sleep, diet, exercise and body fat. In the case of prolonged stress, the production of GH will be increased initially, but overall levels will be reduced significantly over time. An increase in cortisol levels experienced during prolonged stress will inhibit release of GH. Also there will be a reduction in the release of lutenising hormone and testosterone. GH is usually released during the first 30-90 minutes of sleep.

Decreased sleep causes an increase in cortisol and a decrease in GH and testosterone. Also the release of melatonin will be affected and this further reduces the production of GH. Low GH has also been linked to CFS, fibromyalgia, osteoporosis and even leaky gut syndrome. Circulating GH is filtered through the kidneys and whilst most is reabsorbed, a small amount is secreted in the urine, making urine the best medium for testing GH levels.  

Recently we have heard of athletes using human growth hormone to give them the athletic ‘edge’, as it helps to increase lean muscle mass and being a natural hormone cannot be accurately picked up as an anabolic aid, but of course naturopathically speaking we prefer to look at things which influence the reduction of GH and adjust these factors as well as using herbs to influence the natural production of these hormones. In recent years a herb, Tribulus, has gained a reputation as a ‘natural viagra’, but is also known to help in the increase of GH and DHEA levels.

Clinically documented benefits of Tribulus include: GH regulation via Hypothalamic-Pituitary Axis, intensification of protein synthesis (anabolic), male and female fertility, menopause, andropause, impotence, erectile dysfunction and libido enhancement. Adrenal hormones DHEA and Cortisol also play an important role in how well we age.

DHEA, the principle adrenal adrogen, and its sulphonated ester DHEA-S, decrease with age. In addition to its adrogenic function, DHEA has been reported to have multitudinous other functions such as improving carbohydrate metabolism, neurological function and general well-being. Low levels of DHEA-S are involved in the decline in immunity, chronic fatigue, arthridites, insomnia, decreased libido, obesity, depression and osteoporosis.

Cortisol influences the activity of insulin, thyroid hormones and DHEA. Cortisol is involved in balancing blood glucose levels, immune system responses, bone turnover rate, mood and thought, sleep and protein catabolism.

Elevated cortisol is associated with anxiety, insulin resistance, obesity, osteoporosis, sex hormone imbalance, onset insomnia (difficulty getting to sleep), accelerated aging and immune suppression and disrupts gastrointestinal microflora levels causing dysbiosis such as Candida overgrowth. Low cortisol levels on the other hand relate to CFS, depression, PMS, menopause, fibromyalgia, impotence in men, fertility and maintenance insomnia (difficulty staying asleep).

Lastly I would like to discuss the thyroid hormone (TH). Thyroid function has a profound impact on overall health via its modulation of carbohydrates, protein, fat metabolism, vitamin utilisation, mitochondrial function, digestive process, muscle and nerve activity, blood flow, oxygen utilization, hormone secretion and sexual and reproductive health.

An important function of TH is helping the body to convert food into energy and heat. TH exists in two major forms T3 and T4. Levothyroxine (T4) has four iodine atoms per molecule and is an inactive form that converts to T3 and is produced exclusively by the thyroid gland.

Nutritionally the thyroid gland requires Tyrosine and iodine to produce adequate levels of T4. Triiodothyronine (T3) has three iodine atoms per molecule and is eight times more biologically active than T4. It is converted from T4 in the thyroid, brain, liver, blood stream and in various tissues in the body. 90% of circulating T3 is produced by peripheral conversion.

Iodothyronine deidinase (IDI) regulates the conversion of T4 to T3. IDI is expressed in the liver, kidneys, brain, pituitary and brown fat cells with 80% of conversion done in the liver, one can see the importance of a healthy liver to have a healthy thyroid. In conclusion we can see that hormone balance plays an important role in how well we age. Hormone testing request sheets are available through the clinic or your GP. All but the thyroid test are best done by saliva.

Originally published in Here & Now magazine, written by Sue Kira, from True Vitality

Related to - Health | Naturopathy

By Sue Kira

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