The effect of corticotrophin on liver-type lipase activity in adrenals, liver and high-density lipoprotein subfractions in the rat.
Hypercortisolism was induced in rats by the administration of a corticotrophin analogue (Synacthen depot). The effect of this treatment during different periods was studied in normally fed and overnight-fasted rats. The activity of liver-type lipases, i.e., of lipases similar to the heparin-releasable lipase of rat liver (liver lipase), was determined in the adrenal gland and in the liver. Short-term (16 h) treatment had no effect on the lipase activity in the adrenal gland. During prolonged treatment, however, the lipase activity rose to 600-700% of control values in 10 days and from then on remained constant. The effect was similar in fed and overnight-fasted rats. The lipase activity in the liver decreased upon Synacthen administration. In the fed rats a decrease of 25% of the initial value was found after 16 h, 40% after 3 days and 50% after 20 days of treatment. In overnight-fasted rats the lowering of the lipase activity was less marked than in fasted controls. Serum lipid levels and high-density lipoprotein (HDL) subclass concentrations were also measured. The cholesterol concentration in the lipoproteins with a density greater than 1.050 g/ml (HDL) was elevated in rats treated for 3-20 days. If the rats were treated for longer than 10 days, overnight fasting led to a normalization of the HDL-cholesterol levels. After separation of the HDL into two subfractions, a relatively 'light' apolipoprotein E-rich fraction and a more 'heavy' apolipoprotein A-I-rich fraction, in fed and fasted animals treated with Synacthen for 3 days both HDL subfractions were elevated. After 10 days treatment only the apolipoprotein A-I-rich HDL fraction was still enhanced in both fed and fasted rats.
D000311:Adrenal Glands / Q000201:enzymology*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D055598:Chemical Phenomena; D002621:Chemistry; D002784:Cholesterol / Q000097:blood; D003366:Cosyntropin / Q000494:pharmacology; D005215:Fasting; D008049:Lipase / Q000378:metabolism*; D008075:Lipoproteins, HDL / Q000097:blood*; D008099:Liver / Q000201:enzymology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D008075:Lipoproteins, HDL; D003366:Cosyntropin; C006418:adrenocorticotropin zinc; D000324:Adrenocorticotropic Hormone; D002784:Cholesterol; D008049:Lipase