Glucocorticoid synthesis and regulation — MCQs

A scientist is trying to design a drug to modulate cellular metabolism in the treatment of obesity. Specifically, he is interested in understanding how fats are processed in adipocytes in response to different energy states. His target is a protein within these cells that catalyzes catabolism of an energy source. The products of this reaction are subsequently used in gluconeogenesis or β-oxidation. Which of the following is true of the most likely protein that is being studied by this scientist?

A 65-year-old obese man presents to his primary care clinic feeling weak. He was in the military and stationed in Vietnam in his youth. His current weakness gradually worsened to the point that he had to call his son to help him stand to get on the ambulance. He smokes a pack of cigarettes every day and drinks a bottle of vodka a week. He has been admitted for alcohol withdrawal multiple times and has been occasionally taking thiamine, folic acid, and naltrexone. He denies taking steroids. His temperature is 98°F (36.7°C), blood pressure is 170/90 mmHg, pulse is 75/min, and respirations are 20/min. He is obese with a significant pannus. Hepatomegaly is not appreciable. Abdominal striae are present. His workup is notable for the following: Serum: Na+: 142 mEq/L Cl-: 102 mEq/L K+: 3.9 mEq/L HCO3-: 25 mEq/L BUN: 24 mg/dL Glucose: 292 mg/dL Creatinine: 1.5 mg/dL Ca2+: 10.1 mg/dL AST: 7 U/L ALT: 14 U/L 24-hour urinary cortisol: 400 µg (reference range < 300 µg) Serum cortisol: 45 pg/mL (reference range < 15 pg/mL) A 48-hour high dose dexamethasone suppression trial shows that his serum cortisol levels partially decrease to 25 pg/mL and his adrenocorticotropin-releasing hormone (ACTH) level decreases from 10 to 6 pg/mL (reference range > 5 pg/mL). What is the best next step in management?

An investigator studying hormone synthesis and transport uses immunocytochemical techniques to localize a carrier protein in the central nervous system of an experimental animal. The investigator finds that this protein is synthesized together with a specific hormone from a composite precursor. The protein is involved in the transport of the hormone from the supraoptic and paraventricular nuclei to its destination. The hormone transported by these carrier proteins is most likely responsible for which of the following functions?

A 57-year-old presents to your clinic complaining of baldness. He is overweight, has been diagnosed with BPH, and is currently taking atorvastatin for hyperlipidemia. The patient has tried several over-the-counter products for hair-loss; however, none have been effective. After discussing several options, the patient is prescribed a medication to treat his baldness that has the additional benefit of treating symptoms of BPH as well. Synthesis of which of the following compounds would be expected to decrease in response to this therapy?

A newborn female is found to have ambiguous genitalia and hypotension. Laboratory workup reveals hyperkalemia, hyperreninemia, and elevated levels of 17-hydroxyprogesterone in the patient's urine. Which of the following enzymes would you expect to be deficient in this patient?

A 55-year-old man presents to his primary care physician for a new patient appointment. The patient states that he feels well and has no concerns at this time. The patient has a past medical history of hypertension, an elevated fasting blood glucose, and is not currently taking any medications. His blood pressure is 177/118 mmHg, pulse is 90/min, respirations are 16/min, and oxygen saturation is 97% on room air. Physical exam is notable for an obese man with atrophy of his limbs and striae on his abdomen. Laboratory values are notable for a blood glucose of 175 mg/dL. Which of the following is the best next step in evaluation?

A 45-year-old woman presents to her physician with a four-month history of headache. Her headache is nonfocal but persistent throughout the day without any obvious trigger. She was told that it was a migraine but has never responded to sumatriptan, oxygen, or antiemetics. She takes amlodipine for hypertension. She does not smoke. She denies any recent weight loss or constitutional symptoms. Her temperature is 98°F (36.7°C), blood pressure is 180/100 mmHg, pulse is 70/min, and respirations are 15/min. She is obese with posterior cervical fat pads and central abdominal girth. Her neurological exam is unremarkable. In her initial laboratory workup, her fasting blood glucose level is 200 mg/dL. The following additional lab work is obtained and is as follows: Serum: Na+: 142 mEq/L Cl-: 102 mEq/L K+: 4.1 mEq/L HCO3-: 24 mEq/L BUN: 20 mg/dL Glucose: 135 mg/dL Creatinine: 1.3 mg/dL Ca2+: 10.0 mg/dL AST: 8 U/L ALT: 8 U/L 24-hour urinary cortisol: 500 µg (reference range < 300 µg) Serum cortisol: 25 µg/mL (reference range 5-23 µg/dL) 24-hour low dose dexamethasone suppression test: Not responsive High dose dexamethasone suppression test: Responsive Adrenocorticotropin-releasing hormone (ACTH): 20 pg/mL (5-15 pg/mL) Imaging reveals a 0.5 cm calcified pulmonary nodule in the right middle lobe that has been present for 5 years but an otherwise unremarkable pituitary gland, mediastinum, and adrenal glands. What is the best next step in management?

A 5-year-old male visits his pediatrician for a check-up. His height corresponds to the 99th percentile for his age, and pubic hair is present upon physical examination. Serum renin and potassium levels are high, as is 17-hydroxyprogesterone. Which of the following is likely deficient in this patient?

You have been asked to deliver a lecture to medical students about the effects of various body hormones and neurotransmitters on the metabolism of glucose. Which of the following statements best describes the effects of sympathetic stimulation on glucose metabolism?

A 60-year-old man with type 2 diabetes on metformin and insulin presents with 3 days of nausea, vomiting, and diffuse abdominal pain. He appears ill and confused. Vital signs: BP 95/60 mmHg, HR 115/min, RR 28/min, T 37.2°C. Labs show glucose 380 mg/dL, pH 7.28, HCO3 18 mEq/L, anion gap 24, serum osmolality 310 mOsm/kg, negative urine ketones, creatinine 2.8 mg/dL (baseline 1.1), lactate 8.2 mmol/L. Apply physiological principles to determine the primary acid-base and metabolic disturbance.