Which statement best describes the effect of insulin on lipolysis during diabetic ketoacidosis?

• A. Insulin promotes lipolysis, worsening ketoacidosis.
• B. Insulin suppresses lipolysis, helping reduce ketoacidosis.
• C. Insulin has no effect on lipolysis.
• D. Insulin only affects carbohydrate metabolism, not lipids.

Answer: (B)

Insulin’s effect on fat tissue is to restrain lipolysis. In diabetic ketoacidosis, there’s a severe insulin deficiency along with high levels of counterregulatory hormones like glucagon and catecholamines. This combination strongly activates hormone-sensitive lipase in adipose tissue, driving the breakdown of triglycerides into free fatty acids that enter the bloodstream. The liver then converts these fatty acids into ketone bodies, fueling the metabolic acidosis.

When insulin is given, it suppresses lipolysis in adipose tissue. It lowers cAMP levels and activates pathways that deactivate hormone-sensitive lipase, so fewer free fatty acids are released. With less fatty acid supply to the liver, ketone production drops, helping to reverse ketoacidosis and stabilize the patient.

So, the correct idea is that insulin suppresses lipolysis, aiding in the reduction of ketoacidosis. The other statements would imply insulin increases lipolysis, has no effect on lipolysis, or affects only carbohydrates, which isn’t accurate because insulin also modulates lipid metabolism and ketogenesis.