Hepatic Lipidosis Flashcards
describe mobilization of fat
3 phases of fuel metabolism:
1. absorptive/digestion: insulin dependent, anabolic
2. nutrient utilization/post-absorb: insulin independent, use stored glycogen
3. energy deficient/feed deprivation: burn fat first, then protein for energy
fat mobilized as NEFAs, sent to tissues for energy, to mammary glands for milk fat (ruminants), and to liver
in liver:
complete beta-oxidation = energy, yay
incomplete beta-oxidation = ketone bodies, uh oh
converted that NEFA to a VLDL for storage = major uh oh and hepatic lipidosis
compare and contrast pathophysiology of hepatic lipidosis in ruminants, horses, and cats
cows: negative energy balance due to demands of pregnancy and lactation cause mobilization of fat, leads to classic pathway of NEFAs to tissue, to mammary gland, to liver, make ketone bodies and build up VLDL fat in liver
horses: major cause is illness causing off feed or feed deprivation, quick result because constant grazers and even quicker in obese animals (more fat to mobilize), but horses mobilize more VLDLs and triglycerides than ketone bodies, so if suspect hepatic lipidosis, check for triglycerides in blood, if see hypertriglyceridemia, likely hepatic lipidosis
cats: do not synthesize 12 proteinogemic amino acids and must obtain from diet, especially arginine (deficiency leads to hyperammonemia and hepatic encephalopathy) and taurine (synth from cysteine, deficiency increases lipolysis and predisposes to hepatic lipidosis), so anorexia (2-14d) leads to the negative energy balance and predisposing factors to hepatic lipidosis, usually secondary meaning there is an underlying cause;
cats, cont: this negative energy balance results in increased glucagon, cortisol, growth hormone, and catecholamines and DECREASED INSULIN, increasing activity of hormone sensitive lipase, causing all the fat mobilization things that lead to hepatic lipidosis and further increase peripheral insulin resistance; major risk factor is obesity due to more fat to mobilize, more inflammatory adipokines, and insulin resistance
