Metabolic Effects of Insulin and Glucagon

These flashcards cover key vocabulary terms related to the metabolic effects of insulin and glucagon, their functions, mechanisms of action, and physiological impacts.

Insulin

A peptide hormone produced by the β cells of the pancreas that has anabolic effects, promoting glycogenesis, proteogenesis, and lipogenesis.

Glucagon

A peptide hormone secreted by pancreatic α cells that opposes the action of insulin and maintains blood glucose levels through gluconeogenesis and glycogenolysis.

Glycogenesis

The process of converting glucose into glycogen for storage, stimulated by insulin.

Gluconeogenesis

The synthesis of glucose from non-carbohydrate sources, primarily in the liver, stimulated by glucagon.

C-peptide

A connecting peptide released during the conversion of proinsulin to insulin, which helps measure insulin production.

GLUT-4 transporter

A glucose transporter whose activity is increased by insulin, facilitating glucose uptake in muscle and adipose tissue.

Catecholamines

Hormones, such as epinephrine and norepinephrine, released during stress that can inhibit insulin secretion and promote glucagon activity.

Hyperglycemia

A condition characterized by excessively high blood glucose levels, often managed by insulin.

Hypoglycemia

Low blood glucose levels, potentially leading to symptoms such as anxiety, confusion, and in severe cases, coma.

Receptor tyrosine kinase

A type of receptor that, upon binding with insulin, activates phosphorylation cascades that regulate cellular metabolic processes.

Amino acids

Organic compounds that serve as building blocks for proteins; glucagon increases their uptake for gluconeogenesis.

Exocytosis

The process by which insulin is released from pancreatic β cells into the bloodstream.

Hormone-sensitive lipase

An enzyme that breaks down triglycerides; its activity is inhibited by insulin.

Signal sequence

A short peptide chain that directs the transport of a protein to its proper location in the cell; present in preproinsulin.

Endoplasmic reticulum (ER)

The organelle where preproinsulin is synthesized and processed into insulin.

Pancreatic α cells

The cells in the islets of Langerhans that secrete glucagon.

Insulin-degrading enzyme

An enzyme that rapidly degrades insulin, primarily in the liver and kidneys.

Sympathetic nervous system (SNS)

The part of the autonomic nervous system that mediates rapid mobilization of fuels and can inhibit insulin secretion.

Protein phosphatase

An enzyme that removes phosphate groups from proteins; its action can affect the regulation of metabolic pathways stimulated by insulin and glucagon.

Insulin

A peptide hormone produced by the
$\beta$
cells of the pancreas that has anabolic effects, promoting glycogenesis, proteogenesis, and lipogenesis.

Glucagon

A peptide hormone secreted by pancreatic
$\alpha$
cells that opposes the action of insulin and maintains blood glucose levels through gluconeogenesis and glycogenolysis.

Glycogenesis

The process of converting glucose into glycogen for storage, stimulated by insulin.

Gluconeogenesis

The synthesis of glucose from non-carbohydrate sources, primarily in the liver, stimulated by glucagon.

C-peptide

A connecting peptide released during the conversion of proinsulin to insulin, which helps measure insulin production.

GLUT-4 transporter

A glucose transporter whose activity is increased by insulin, facilitating glucose uptake in muscle and adipose tissue.

Catecholamines

Hormones, such as epinephrine and norepinephrine, released during stress that can inhibit insulin secretion and promote glucagon activity.

Hyperglycemia

A condition characterized by excessively high blood glucose levels, often managed by insulin.

Hypoglycemia

Low blood glucose levels, potentially leading to symptoms such as anxiety, confusion, and in severe cases, coma.

Receptor tyrosine kinase

A type of receptor that, upon binding with insulin, activates phosphorylation cascades that regulate cellular metabolic processes.

Amino acids

Organic compounds that serve as building blocks for proteins; glucagon increases their uptake for gluconeogenesis.

Exocytosis

The process by which insulin is released from pancreatic
$\beta$
cells into the bloodstream.

Hormone-sensitive lipase

An enzyme that breaks down triglycerides; its activity is inhibited by insulin.

Signal sequence

A short peptide chain that directs the transport of a protein to its proper location in the cell; present in preproinsulin.

Endoplasmic reticulum (ER)

The organelle where preproinsulin is synthesized and processed into insulin.

Pancreatic
$\alpha$
cells

The cells in the islets of Langerhans that secrete glucagon.

Insulin-degrading enzyme

An enzyme that rapidly degrades insulin, primarily in the liver and kidneys.

Sympathetic nervous system (SNS)

The part of the autonomic nervous system that mediates rapid mobilization of fuels and can inhibit insulin secretion.

Protein phosphatase

An enzyme that removes phosphate groups from proteins; its action can affect the regulation of metabolic pathways stimulated by insulin and glucagon.

Proinsulin

The precursor protein to insulin, which is cleaved to yield mature insulin and C-peptide.

Pancreatic
$\beta$
cells

The cells in the islets of Langerhans that produce and secrete insulin.

Glycogenolysis

The breakdown of glycogen into glucose, primarily in the liver and muscles, stimulated by glucagon.

Lipogenesis

The metabolic process of synthesizing fatty acids and triglycerides for fat storage, stimulated by insulin.

Proteogenesis

The synthesis of proteins from amino acids, a process promoted by insulin.