Question 1

What is the Meaning of GH-Induced Insulin Resistance?

Accepted Answer

Growth Hormone-Induced Insulin Resistance refers to a physiological state where the presence of elevated growth hormone levels diminishes the body's sensitivity to insulin, leading to reduced glucose uptake by cells and increased glucose production by the liver. This condition results in higher circulating blood glucose concentrations, as insulin becomes less effective at regulating blood sugar. It represents a counter-regulatory action of growth hormone on glucose metabolism.

Question 2

What is the Context of GH-Induced Insulin Resistance?

Accepted Answer

This phenomenon operates within the complex interplay of the endocrine system, specifically involving hormones like growth hormone, insulin, and glucagon, which collectively regulate energy balance and glucose homeostasis. Growth hormone, secreted by the pituitary gland, exerts direct and indirect metabolic effects, influencing carbohydrate, protein, and lipid metabolism. Its counter-regulatory influence on insulin is a key aspect of its physiological role in maintaining glucose availability.

Question 3

What is the Significance of GH-Induced Insulin Resistance?

Accepted Answer

Understanding GH-induced insulin resistance holds considerable clinical importance, particularly in the diagnosis and management of endocrine disorders such as acromegaly, a condition characterized by chronic growth hormone excess. Patients with acromegaly frequently exhibit impaired glucose tolerance or overt type 2 diabetes mellitus due to this resistance. Clinicians must consider this mechanism when assessing metabolic health in individuals with altered growth hormone secretion or during therapeutic growth hormone administration.

Question 4

What is the Mechanism of GH-Induced Insulin Resistance?

Accepted Answer

The cellular mechanism involves growth hormone directly antagonizing insulin signaling pathways primarily at post-receptor levels. Growth hormone interferes with the phosphorylation of insulin receptor substrate-1 (IRS-1) and subsequent activation of the PI3K/Akt pathway, which are crucial for glucose transporter (GLUT4) translocation and glucose uptake in insulin-sensitive tissues like skeletal muscle and adipose tissue. Additionally, growth hormone promotes hepatic gluconeogenesis, further contributing to elevated blood glucose.

Question 5

What is the Application of GH-Induced Insulin Resistance?

Accepted Answer

Clinically, this resistance is evident in patients with acromegaly, who often present with metabolic complications including glucose intolerance and diabetes, necessitating careful glycemic monitoring and management. In therapeutic settings where exogenous growth hormone is administered, such as for growth hormone deficiency, clinicians anticipate a potential decrease in insulin sensitivity and monitor glucose parameters, especially in patients with pre-existing metabolic risk factors. Dietary and lifestyle interventions often complement medical management.

Question 6

What is the Metric of GH-Induced Insulin Resistance?

Accepted Answer

The presence and severity of insulin resistance induced by growth hormone can be assessed through various biochemical metrics. Fasting glucose and insulin levels are commonly measured, and the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) provides an estimate of insulin sensitivity. An oral glucose tolerance test (OGTT) can reveal impaired glucose tolerance, while glycated hemoglobin (HbA1c) offers a long-term indicator of average blood glucose control.

Question 7

What is the Risk of GH-Induced Insulin Resistance?

Accepted Answer

Uncontrolled or prolonged GH-induced insulin resistance poses significant health risks, predominantly increasing the likelihood of developing or worsening type 2 diabetes mellitus. Chronic hyperglycemia can lead to microvascular complications such as retinopathy, nephropathy, and neuropathy, as well as macrovascular complications including cardiovascular disease and stroke. Therefore, diligent monitoring and appropriate therapeutic interventions are essential to mitigate these adverse outcomes.

GH-Induced Insulin Resistance

Meaning

Context

Significance

Mechanism

Application

Metric

Risk

How Do Lifestyle Factors like Diet and Exercise Modulate Insulin Sensitivity during GH Therapy?