Glucagon physiology — MCQs

A 24-year-old man presents for an annual check-up. He is a bodybuilder and tells you he is on a protein-rich diet that only allows for minimal carbohydrate intake. His friend suggests he try exogenous glucagon to help him lose some excess weight before an upcoming competition. Which of the following effects of glucagon is he attempting to exploit?

A 32-year-old woman is found unconscious on the office floor just before lunch by her colleagues. She had previously instructed them on the location of an emergency kit in case this ever happened so they are able to successfully inject her with the substance inside. Her past medical history is significant for type 1 diabetes for which she takes long acting insulin as well as periprandial rapid acting insulin injections. She has previously been found unconscious once before when she forgot to eat breakfast. The substance inside the emergency kit most likely has which of the following properties.

A 55-year-old man with alcoholic cirrhosis is admitted to the hospital for routine evaluation before liver transplantation. The physician asks the patient to stop eating 10 hours before surgery. Which of the following structures contributes directly to preventing fasting hypoglycemia by producing glucose in this patient?

A 53-year-old man comes to the physician because of fatigue, recurrent diarrhea, and an 8-kg (17.6-lb) weight loss over the past 6 months. He has a 4-month history of recurrent blistering rashes on different parts of his body that grow and develop into pruritic, crusty lesions before resolving spontaneously. Physical examination shows scaly lesions in different phases of healing with central, bronze-colored induration around the mouth, perineum, and lower extremities. Laboratory studies show: Hemoglobin 10.1 mg/dL Mean corpuscular volume 85 μm3 Mean corpuscular hemoglobin 30.0 pg/cell Serum Glucose 236 mg/dL Abdominal ultrasonography shows a 3-cm, solid mass located in the upper abdomen. This patient's mass is most likely derived from which of the following types of cells?

A 45-year-old man comes to the physician for evaluation of a recurrent rash. He has multiple skin lesions on his legs, buttocks, and around his mouth. The rash first appeared a year ago and tends to resolve spontaneously in one location before reappearing in another location a few days later. It begins with painless, reddish spots that gradually increase in size and then develop into painful and itchy blisters. The patient also reports having repeated bouts of diarrhea and has lost 10 kg (22 lb) over the past year. One year ago, the patient was diagnosed with major depressive syndrome and was started on fluoxetine. Vital signs are within normal limits. Physical examination shows multiple crusty patches with central areas of bronze-colored induration, as well as tender eruptive lesions with irregular borders and on his legs, buttocks, and around his lips. The Nikolsky sign is negative. His hemoglobin concentration is 10.2 g/dL, mean corpuscular volume is 88 μm3, and serum glucose is 210 mg/dL. A skin biopsy of the lesion shows epidermal necrosis. Which of the following additional findings is most likely to be found in this patient?

A 16-year-old girl is brought to the emergency department unresponsive. A witness reports that she became anxious, lightheaded, and began sweating and trembling a few minutes before she lost consciousness. Her vitals are as follows: blood pressure 95/60 mm Hg, heart rate 110/min, respiratory rate 21/min, and temperature 35.5°C (95.5°F). She becomes responsive but is still somnolent. She complains of dizziness and weakness. A more detailed history reveals that she has drastically restricted her diet to lose weight for the past 18 hours, and has not eaten today. Her skin is pale, wet, and cold. The rest of the physical examination is unremarkable. Blood testing shows a plasma glucose level of 2.8 mmol/L (50.5 mg/dL). Which of the following statements is true?

Which hormone most strongly stimulates gluconeogenesis during prolonged fasting?

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.

A 38-year-old woman presents with hypertension (170/105 mmHg), hypokalemia (2.9 mEq/L), and metabolic alkalosis. Plasma aldosterone is elevated at 35 ng/dL (normal 4-31) and plasma renin activity is suppressed at 0.2 ng/mL/hr (normal 0.5-3.5). CT scan shows a 2.5 cm left adrenal mass. She also reports recent diagnosis of hyperthyroidism and is being evaluated for a neck mass. Synthesize these findings to evaluate for an underlying unifying diagnosis requiring modified treatment approach.

A 32-year-old pregnant woman at 28 weeks gestation with type 1 diabetes presents with recurrent severe hypoglycemia despite reducing her insulin dose. Her insulin requirements have decreased by 40% over the past week. She reports decreased fetal movement. Fetal ultrasound shows intrauterine fetal demise. Evaluate the physiological mechanism explaining her changing insulin requirements in the context of pregnancy loss.