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.
-The neuroendocrine signaling cascade that induces adrenal hyperplasia involves coordinated activity among which organs?

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.
-The neuroendocrine signaling cascade that induces adrenal hyperplasia involves coordinated activity among which organs?

Quizplus · Accepted Answer

11ecba2d_0fcc_b060_a3bf_7b5c6fc7043e_MD0008_00 The hypothalamus is a brain structure located inferior to the thalamus that regulates the synthesis and secretion of multiple classes of hormones. It serves as the interface between the nervous and endocrine systems by processing both cortical inputs from the brain and sensing the plasma concentration of numerous hormones. In response to these inputs, the hypothalamus controls body-wide endocrine function by influencing activity within the pituitary gland, an endocrine organ located inferior to the hypothalamus that is composed of a posterior and an anterior lobe. The posterior lobe of the pituitary gland contains the axonal processes of hypothalamic neurons. The hormones antidiuretic hormone (ADH) and oxytocin are synthesized by these specialized neurons and stored within their axon terminals, which form junctions with systemic blood vessels. As a result, the firing of hypothalamic neurons results in the release of ADH or oxytocin into the systemic circulation. The hypothalamus controls the anterior lobe of the pituitary gland by releasing signaling molecules into the hypophyseal portal system, a localized network of blood vessels that bridges the hypothalamus and anterior pituitary. These signaling molecules promote or inhibit the release of specific hormones into the systemic circulation by the anterior pituitary gland. For example, corticotrophin-releasing hormone (CRH) released by the hypothalamus stimulates the anterior pituitary to release adrenocorticotropic hormone (ACTH) into the systemic circulation. ACTH then acts on the adrenal glands to promote synthesis and secretion of glucocorticoids, completing the neuroendocrine pathway that regulates the serum level of cortisol and other glucocorticoids. (Choices A and D) The parathyroid glands secrete parathyroid hormone (PTH), which functions to regulate serum Ca²⁺ levels. The parathyroid gland does not directly regulate the synthesis and secretion of glucocorticoids. (Choice C) Although the liver is responsible for numerous functions (eg, carbohydrate and fat metabolism), it is not involved in neuroendocrine control of the adrenal glands. Educational objective: The hypothalamus is a brain structure that regulates numerous endocrine functions through its association with the pituitary gland. Together, the hypothalamus and pituitary gland regulate the synthesis and secretion of hormones that influence metabolism, reproduction, and other important functions.

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