Three basic pathophysiologic mechanisms lead to
virtually all the clinical disease states involving endocrine glands:
(46) the excessive hormone production and action and
neoplasa. Deficiency of hormone action is most commonly
caused by an abnormally low level of biologically active hormone reaching target
tissues. (47) Endocrine gland hypofunciton may be
congenital, caused by a complete failure of gland development, a mutant
gene-encoding the structure of hormone or an enzyme responsible for hormone
biosythesis. (48) replacement by tumor,
surgical extirpation, effects of pharmacologic or environmental agents, or
inflammation. Other causes of decreased hormone action in
target tissues are encountered less frequently. Deranged physiologic control of
pituitary gland function causes secondary glandular failure, which can be either
congenital or acquired (49) Defective postsecretory hormone
activation or accelerated hormone metabolism may result in abnormally low
hormone activity. Hormonal deficiency states, despite normal
or even elevated concentrations of biologically active hormone in the
circulation, may be due to target-tissue resistance.
(50) This failure of target tissue responsiveness may be due to
an abnormality of hormone receptors or in post-binding signaling of the
hormone-receptor interaction.
A. Deficiency of hormone action on target tissues.
B. Improvement of hormone release may result in glandular hypofunction.
C. Functional endocrine tumors secrete a hormonal product.
D. Inadequate hormone production may occur as a result of primary gland
failure.
E. Resistance can be congenital or acquired F. Endocrine gland
failure may also be acquired as a consequence of physiologic
atrophy.