This example asks you to imagine that you are a doctor. You have a male patient showing low levels of thyroid hormone or T4, low levels of cortisol, produced in the adrenal cortex, and low levels of testosterone in a male, which would be produced in the testes. You believe the cause is a tumor in the hypothalamus. Now, based on your understanding of the role of the hypothalamus in the endocrine system, would you expect the tumor to be blocking the normal function of the hypothalamus or causing overstimulation of the hypothalamus? And explain your reasoning.
Alright. Take a second and think that through. If you are not producing enough thyroid hormone, cortisol, and testosterone and the cause is a tumor in the hypothalamus, would you think that is due to blocking the hypothalamus function or overstimulating the hypothalamus? Well, let's think about that, and let's sort of walk this all back. We are talking about thyroid hormone made in the thyroid gland, cortisol made in the adrenal cortex, and testosterone made in the testes. Now the release of all those hormones is going to be influenced by tropic hormones from the anterior pituitary gland. Specifically, thyroid-stimulating hormone (TSH) will stimulate the release of thyroid hormone. Adrenocorticotropic hormone (ACTH) will stimulate the release of cortisol. And, luteinizing and follicle-stimulating hormones will influence the release of testosterone.
So, if you're not producing enough of those hormones, there is a good chance the pituitary gland is not producing enough of those tropic hormones. But those tropic hormones from the anterior pituitary get released when the pituitary gland is stimulated by tropic hormones from the hypothalamus. So if the anterior pituitary gland isn't producing enough, there is a good chance it's because the hypothalamus is not producing enough of its tropic hormones. And so, if it's not producing enough, that says to me that this would be blocking the function of the hypothalamus.
Now, my reasoning we have just sort of gone through. Now, in I'm going to state it in real simple terms. I would just say that tropic hormones cause the release of other hormones. And now if this were a test, obviously, I would say a lot more than that. I'd start with that, and then I would say how the hypothalamus releases tropic hormones that affect the pituitary gland, which causes the release of hormones from the pituitary gland. The pituitary gland releases tropic hormones, which cause the release of these hormones we are talking about. So, if these hormones are not being released at a high enough level, there is a decent chance that we can follow it all the way back, and the tropic hormones from the hypothalamus are also not being released at a high enough level. That is my answer. We have more practice problems to follow. I'll see you there.