The ZRT Laboratory Blog

The ZRT Blog is an extensive resource for patients and health care providers searching for health and hormone testing information. Here, you can read about ZRT’s cutting edge research, advances in testing, wellness advice, and health industry highlights.

Neurotransmitters, Mood & the Perception of Stress

Posted by Dr. Thomas Guilliams on Friday, 06 April

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When we talk about “stress,” or allostatic load, in terms of the perception of an event, we must realize that these “events” must first be translated into neurochemical signals before they trigger the HPA axis.

Therefore, the sensitivity and outcome of translating these events (whether they are ongoing events, memories of past events, or stressful anticipation of unrealized events), is highly dependent upon signaling from other neurotransmitters. In fact, the signaling neurotransmitters that manage mood and affect often overlap with measures of HPA axis activation, and cannot be easily distinguished in some subjects. [1]

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Avoiding 3 Common Interpretation Pitfalls for Salivary Cortisol Tests

Posted by Dr. Allison Smith on Tuesday, 08 August

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One of ZRT's most popular tests includes diurnal assessment of a patient's salivary cortisol levels. On the surface, these tests seem easy enough to interpret, but experienced clinicians know there can sometimes be pitfalls.

Patients testing cortisol in a clinical setting may take undisclosed medications, live under stressful conditions, have inflammation, genetic variations, tumors, and diseases. Sleuthing out the cause of cortisol elevations and depressions can be a real challenge.

To avoid unnecessary work-ups, there are a few areas to consider when interpreting a salivary cortisol test – Contamination, Suppression, and Comorbidities.

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Pheochromocytoma - A Rare Condition Exposed by Neurotransmitter Testing

Posted by Dr. Alison McAllister on Wednesday, 28 June

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The New York Times did a remarkable story the other day that ended with the line "When you hear hoofbeats, the chances are good that it's a horse…but we must also remember that sometimes the circus is in town. [1]

ZRT is apparently hosting the circus this year. At the odds of 3-8 individuals per million – ZRT has been instrumental in discovering two cases of pheochromocytoma tumors in the last six months. A condition that my clinical physiology teacher, Dr. Bettenburg, said was so rare that we would never see one, and if we did, we should contact her – so I did, this week. 

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Re-assessing the Notion of "Pregnenolone Steal"

Posted by Dr. Thomas Guilliams on Wednesday, 21 June

ThinkstockPhotos-687447022-pregnenolone-.jpgWhen clinicians measure salivary cortisol and DHEA (DHEA-S) to assess stress and HPA axis function, it is common to find DHEA levels below the reference range in a number of individuals. A common explanation for the depletion of DHEA and other hormones (e.g., progesterone, testosterone) due to chronic stress is the phenomenon known as "pregnenolone steal."

The pregnenolone steal notion states that since all steroid hormones use pregnenolone (derived from cholesterol) as a precursor, the elevated secretion of cortisol caused by acute or chronic stress will inevitably result in less available pregnenolone to serve as a precursor for the production of DHEA and other down-stream hormones.

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