Passage
A 6-day-old, genotypically normal (46,XX) female patient shows symptoms of hypoglycemia (low blood glucose) and hypotonia (decreased muscle tone). Physical examination reveals abnormal development of the external genitalia, and laboratory studies show elevated urinary sodium content, increased serum levels of potassium, and abnormal serum concentration of several steroid hormones. The patient is diagnosed with 21-hydroxylase deficiency, the most common type of congenital adrenal hyperplasia (CAH).CAH refers to a group of autosomal recessive diseases, each associated with defective production of one or more steroid hormones by the adrenal glands, two crescent-shaped glands located above each kidney in the abdominal cavity. It has been reported that unequal crossing over involving chromosome 6 can result in CAH. More than 90% of CAH diagnoses are associated with a deficiency of 21-hydroxylase, an enzyme encoded by the CYP21A2 gene on chromosome 6.Normally, 21-hydroxylase catalyzes chemical reactions involved in the synthesis of aldosterone and cortisol, the principal mineralocorticoid and glucocorticoid hormones, respectively. As a result, patients with 21-hydroxylase deficiency exhibit diminished serum levels of aldosterone and cortisol. However, synthesis and secretion of the sex hormone testosterone is excessive. Glucocorticoid deficiency disrupts the negative feedback loop linking the brain to the adrenal gland, leading to hyperplasia (increased cell proliferation) of adrenal tissue.The patient's 21-hydroxylase deficiency is treated with regular administration of synthetic steroid hormones. Her condition improves after receiving these medications.
-Glucocorticoid deficiency is known to impair healing of superficial wounds, memory formation, and other physiologic phenomena. This deficiency most likely leads to these wide-ranging effects because:

Question

Passage
A 6-day-old, genotypically normal (46,XX) female patient shows symptoms of hypoglycemia (low blood glucose) and hypotonia (decreased muscle tone).  Physical examination reveals abnormal development of the external genitalia, and laboratory studies show elevated urinary sodium content, increased serum levels of potassium, and abnormal serum concentration of several steroid hormones.  The patient is diagnosed with 21-hydroxylase deficiency, the most common type of congenital adrenal hyperplasia (CAH).CAH refers to a group of autosomal recessive diseases, each associated with defective production of one or more steroid hormones by the adrenal glands, two crescent-shaped glands located above each kidney in the abdominal cavity.  It has been reported that unequal crossing over involving chromosome 6 can result in CAH.  More than 90% of CAH diagnoses are associated with a deficiency of 21-hydroxylase, an enzyme encoded by the CYP21A2 gene on chromosome 6.Normally, 21-hydroxylase catalyzes chemical reactions involved in the synthesis of aldosterone and cortisol, the principal mineralocorticoid and glucocorticoid hormones, respectively.  As a result, patients with 21-hydroxylase deficiency exhibit diminished serum levels of aldosterone and cortisol.  However, synthesis and secretion of the sex hormone testosterone is excessive.  Glucocorticoid deficiency disrupts the negative feedback loop linking the brain to the adrenal gland, leading to hyperplasia (increased cell proliferation) of adrenal tissue.The patient's 21-hydroxylase deficiency is treated with regular administration of synthetic steroid hormones.  Her condition improves after receiving these medications.
-Glucocorticoid deficiency is known to impair healing of superficial wounds, memory formation, and other physiologic phenomena.  This deficiency most likely leads to these wide-ranging effects because:

Quizplus · Accepted Answer

11ecba2d_0fcb_ed0f_a3bf_5fa8edc32837_MD0008_00 Hormones are chemical messengers that influence physiologic function through endocrine signaling, a form of long-distance cell-to-cell communication. In endocrine signaling, hormones are secreted into the bloodstream by specialized cells and transported throughout the body via the circulatory system. Once the hormone reaches its target tissue, it alters cellular function in one of the following ways: Water-soluble (hydrophilic) hormones generally bind a cell surface receptor and initiate a second messenger cascade, leading to changes in protein activity (eg, enzymes, membrane channels). Water-insoluble (hydrophobic) hormones generally diffuse across the lipid bilayer of the plasma membrane and bind to a cytosolic receptor to ultimately regulate gene expression in the nucleus. Hormones affect the function of diverse and distant tissues in the body. This is because hormone receptors can be expressed in a variety of cell types located throughout the body, and any cell that expresses the correct receptor is capable of responding to the receptor's ligand (hormone). For example, glucocorticoids released into the bloodstream from the adrenal cortex influence the energy metabolism of skeletal muscle cells, liver cells, and fat cells, which all express glucocorticoid receptors. However, in glucocorticoid deficiency, an insufficient amount of glucocorticoid hormones in the blood leads to diminished binding of these hormones to their receptors. This condition would compromise the normal function of the various cells that express glucocorticoid receptors. (Choice A) Although glucocorticoid signaling increases serum glucose levels by promoting gluconeogenesis, the widespread effects of glucocorticoid deficiency are better explained by the diminished activation of body-wide glucocorticoid receptors due to the decreased overall synthesis and secretion of glucocorticoids. (Choice C) Glucocorticoids do not affect thyroid hormone secretion by the thyroid gland. (Choice D) Tissue damage caused by adrenal gland enlargement would have no direct effect on activities such as memory formation and the healing of superficial wounds because these functions occur outside the abdominal cavity. Educational objective: Hormones are a diverse group of molecules that participate in endocrine signaling, a form of long-distance cell-to-cell communication. Any cell type that expresses a hormone receptor will respond to serum levels of the hormone.

Passage a 6-Day-Old, Genotypically Normal (46,XX) Female Patient Shows Symptoms of of Hypoglycemia