WBR0601

Author	[[PageAuthor::Ayokunle Olubaniyi, M.B,B.S [1] (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Physiology
Sub Category	SubCategory::Endocrine
Prompt	[[Prompt::A 58-year-old woman recently diagnosed type 2 diabetes mellitus presents to the clinic for follow-up of her blood glucose concentration. Her fasting glycemia is 81 mg/dL (4.5 mmol/L) and she is doing well on diet and exercise alone. The patient asks about her need for insulin therapy and how insulin is involved in metabolism. Which of the following cells requires insulin for glucose uptake?]]
Answer A	AnswerA::Brain cells
Answer A Explanation	AnswerAExp::Brain cells take up glucose through the activity of GLUT-1 (Glucose Transporter-1)
Answer B	AnswerB::Liver cells
Answer B Explanation	AnswerBExp::Liver cells take up glucose through the activity of GLUT-2
Answer C	AnswerC::Skeletal muscle
Answer C Explanation	AnswerCExp::Skeletal muscle contains GLUT-4 but they require the action of insulin for glucose uptake
Answer D	AnswerD::Kidney
Answer D Explanation	AnswerDExp::Liver cells take up glucose through the activity of GLUT-4
Answer E	AnswerE::Red blood cells
Answer E Explanation	AnswerEExp::Liver cells take up glucose through the activity of GLUT-4
Right Answer	RightAnswer::C
Explanation	[[Explanation::Insulin is an anabolic hormone produced in the beta cells of the pancreas. It is involved in numerous processes in the body, such as fatty acid synthesis, protein synthesis, and glucose metabolism. In glucose metabolism, insulin is needed for the transport of glucose into cells in skeletal muscles and adipose tissue. Some organs (brain, RBCs, intestine, cornea, kidney, liver, and beta islet cells of the pancreas) do not require insulin for glucose uptake. Glucose transporters are required for uptake of glucose into many organs. There are several subtypes of glucose transporters: GLUT-1: RBCs, brain cells, cornea GLUT-2 - Has bidirectional activity: Renal tubular cells, small intestinal epithelial cells, liver cells, and pancreatic beta cells GLUT-3: Neurons, placenta GLUT-4 – Insulin-responsive transport: Skeletal muscle, adipose tissue GLUT-5: Intestinal epithelium Educational Objective: In glucose metabolism, insulin is needed for the transport of glucose into cells in skeletal muscles and adipose tissue. Some organs (brain, RBCs, intestine, cornea, kidney, liver, and beta islet cells of the pancreas) do not require insulin for glucose uptake. References: First Aid 2015 page 314]]
Approved	Approved::Yes
Keyword	WBRKeyword::Insulin, WBRKeyword::Glucose transporters, WBRKeyword::Glucose uptake, WBRKeyword::Insulin-responsive, WBRKeyword::GLUT
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::