Hepatic ketogenesis

Hepatic ketogenesis is a **metabolic pathway** occurring primarily in the mitochondria of liver cells, where fatty acids and certain ketogenic amino acids are broken down to produce **ketone bodies**—mainly acetoacetate, beta-hydroxybutyrate, and acetone[2][7]. This process is activated when carbohydrates are scarce, such as during fasting, starvation, prolonged exercise, low-carbohydrate diets, or untreated type 1 diabetes[2][5]. The main steps involve β‑oxidation of fatty acids to acetyl-CoA; condensation to acetoacetyl-CoA; conversion by HMG-CoA synthase to HMG-CoA; cleavage by HMG-CoA lyase to form acetoacetate; with further reduction or decarboxylation yielding beta-hydroxybutyrate and acetone[7]. Ketones produced by the liver serve as an alternative energy source for extrahepatic tissues like brain and muscle when glucose availability is limited. The process also helps prevent hepatic injury from excess fat accumulation by diverting carbon away from the TCA cycle into exportable fuel for other organs[1][3]. Impaired hepatic ketogenesis has been linked with increased risk of steatosis and progression toward more severe forms of fatty liver disease such as MASH/MAFLD[4][5]. Hepatic ketogenesis itself is not a single molecular target but rather a pathway involving several enzymes—most notably mitochondrial 3-hydroxy‑3-methylglutaryl–CoA synthase 2 (**HMGCS2**) as the rate-limiting enzyme. Therefore "hepatic ketogenesis" should not be considered a canonical therapeutic target like an individual receptor or enzyme but rather describes a physiological process involving multiple molecular components. Because it refers to a pathway/process rather than an individual molecule/protein/receptor/enzyme/transporter/etc., this entry should be flagged as incorrect for use as a canonical drug target. For structured data purposes on drug targets, consider instead specific enzymes such as "Mitochondrial 3-hydroxy‑3-methylglutaryl–CoA synthase" (HMGCS2)[3][7].

Other names

Ketone body synthesis (in liver)Liver ketone productionHepatic ketone body formation