We have now completed the study of the glucocorticoids secreted by the zona fasciculata of the adrenal glands, which covers everything there is to know about the cortisol family. Now we need to review the by-products of the zona reticularis (located closer to the adrenal cortex, between the zona fasciculata and medulla), the androgens.
As their name suggests, here we're talking about sex hormones or their precursors. This layer of the adrenal cortex has the capacity to secrete the full range of sex hormones (in both sexes, as each gender expresses a full set of hormones, although obviously in different ratios): oestrogens (17-beta-oestradiol and oestrone), progesterone and androgens (testosterone, androstenediol, androstenedione, and dehydroepiandrosterone or DHEA).
It is the latter, DHEA (measured in the blood in its sulphate form) that is of primary interest here because it constitutes by far the dominant androgen adrenal hormone. Measuring DHEA sulphate in the blood allows us to evaluate the whole activity of the zona reticularis at a glance. The levels vary between men (more) and women (less), by about 60%. DHEA has a ubiquitous role and can be transformed into all sex hormones according to individual needs.
Androgen function can also be evaluated more comprehensively through analysis of 24-hour urine collection, thus bypassing the fluctuations of the 24-hour circadian rhythm. The liver detoxification of the androgens can be measured in the same way as the metabolites of cortisol. The metabolites of DHEA are called urinary 17-ketosteroids. In this instance only the total number matters, not the detail of the by-products as this only reflects the diversity of hepatic genes.
The clinical picture of DHEA deficiency does not differ that much from that of cortisol. Common signs are fatigue, forgetfulness, poor sleep, and lowered immunity. Some symptoms are however more specific to low DHEA, even if they have nothing pathognomonic (meaning the same symptoms can be found in other diseases) such as muscular and joint pains, anxiety, depression, low libido (especially with women) and erectile dysfunction (in men, of course!).
Clinical signs may be more suggestive of a lack of DHEA: loss of hair (especially armpits and pubic) and blepharitis (inflammation of the edge of the eyelids which gives a characteristic redness). Additional signs are dry skin, dry and dull hair, dry and dull eyes, poor muscle tone, sometimes with weight gain around the waist … in short not a very good picture!
To close this series on the adrenal glands, a quick review of the products of the secretion of the outermost layer of the adrenal cortex, called the zona glomerulosa, should be done. They are the mineralocorticoids. Their main molecule is aldosterone but they also include, among others, 11-desoxycorticosterone.
When it comes to testing, there is an issue which originates from whether the patient is either standing or sitting, thus serum levels of aldosterone can be highly variable, whereas testing via 24-hour urine collection is more reliable by avoiding the large and constant blood fluctuations.
The dominant symptom of aldosterone deficiency is orthostatic hypotension (e.g. standing) but also by: low blood pressure, an obvious lack of concentration, and fatigue that becomes worse in the afternoon. The patient also has irresistible urges for salt, and, if drinking water, will need to go to the toilet rapidly and the urine output will be abnormally abundant and transparent.