The underlying hormone problem in SARD dogs is a failure to produce cortisol. This results in a rise of adrenal sex steroids. In humans this condition is called Non-Classic/Adult Onset Congenital Adrenal Hyperplasia or CAH. (CAH is possibly the most confusing name ever given to a disease process but that’s a topic for another post.) While the cortisol deficiency is the same in both man and dog, there is also a major difference between the species that’s worth mentioning.
In both humans and dogs, adrenal enzymes no longer do their work. In this case, the enzymes no longer produce cortisol.
When adrenal glands can no longer produce cortisol, the building blocks of cortisol – the supply chain – is shunted down a different production pathway. The sex-steroid pathway. This causes a rise in sex steroid levels.
In both man and dog, low dose daily cortisol replacement corrects this problem.
Look closely at the chart below. In humans, the excess production stops with adrenal testosterone. Adult-onset CAH patients develop signs of testosterone such as excess body hair, obesity, excessive appetite, acne, etc.
When DOGS cannot make sufficient cortisol the results are slightly different. In dogs, excess production continues all the way to the end of the pathway ending in excess estrogen. So, in addition to the excess adrenal testosterone, these dogs also develop signs excess estrogen, one of the most potent steroids.
Estrogen is molecularly very similar to cortisol, so it causes many of the same signs/symptoms of excess cortisol. This is the reason that excess estrogen mimics Cushing’s disease. Excess estrogen is responsible for the elevated liver, kidney, and pancreas readings. It breaks down soft tissue. it causes seizures, tremors and head tics. In excess, it is a known excitotoxin. That means it speeds up the communications in nerve and retinal cells effectively causing a seizure.
To recap: Excess production in humans ends at the level of testosterone. Excess production in dogs ends at the level of estrogen.
This explans why SARD is not diagnosed in humans. Since humans do not produce the excess estrogen, they do not experience the same kind of seizure / excitotoxicity issues that dogs do. This hormonal difference is one reason SARD is diagnosed in dogs but not in humans.