Serum lipoproteins in chickens after administration of adrenocorticotropin or exposure to high temperature.

The effects of intramuscular injections of adrenocorticotropin (ACTH) or short-term exposures to high environmental temperature (44 to 46 C) were determined on the relative amounts of lipoproteins in the serum of 6 to 7-week-old White Rock chickens. In addition, the influence of the sex of the bird and fasting vs. ad libitum feeding on these lipoproteins was measured. The relative amount of high density lipoprotein (HDL) was lowered by ACTH, and heat exposure lowered both HDL and very low density lipoprotein (VLDL). Fasting completely eliminated VLDL and lowered low density lipoprotein (LDL) but had little effect on HDL. The temperature treatments significantly increased serum corticosteroid levels in both sexes in birds fed ad libitum but only in the males of fasted birds. Fasting for 15 hr did not significantly affect serum corticosteroid levels.