The Effects of Insulin, Glucagon and Adrenocorticotrophic Hormone on the Plasma Glucose and Free Fatty Acids of the Domestic Fowl

Abstract

The level of plasma free fatty acids (FFA) in both laying and immature non-laying hens was not markedly decreased by intravenously injected amounts of glucose sufficient to double the level of plasma glucose for 15\p=n-\30min. This was true for fasting and for fed birds. Adrenocorticotrophic hormone (ACTH) given i.v. to laying birds produced a definite increase in the levels of plasma FFA and glucose in doses of 60 i.u./kg. Daily doses of long-acting ACTH given i.m. for 3 days to laying birds produced a marked increase in plasma glucose accompanied by a pronounced fall in plasma FFA. Insulin markedly lowered the plasma glucose level in both mature and immature birds and caused a large and immediate increase in plasma FFA. Glucagon also induced a marked increase in plasma FFA accompanied by a rise in plasma glucose. The effects of insulin and glucagon were not abolished by pretreating the birds with reserpine or hexamethonium bromide. It is concluded that the effect of glucagon on plasma FFA is probably a result of a direct action on avian adipose tissue and that insulin may promote a similar response by an increased release of glucagon from the pancreas.

Development of Hepatic Acetyl Coenzyme A Carboxylase in Hormone-Treated Chicks

“…Both elevate the cyclic AMP levels in liver; insulin potentiates the lipolytic effect of glucagon, increasing the free fatty acids in plasma (9,17,19,20). Further more, glucagon is the most important hormone in the carbohydrate metabolism in birds; its content is 10 times that found in mammals (6,16).…”

Chickens from lines artificially selected for juvenile low and high body weight differ in glucose homeostasis and pancreas physiology

“…Despite the similar potencies of chicken and mammalian insulin in vitro (Goodridge, 1968;Hazelwood et al, 1968;Langslow and Hales, 1969), as well as similar half-lives in chicken plasma (Langslow and Freeman, 1972), chickens require a dose of 50 i.u./kg body weight to produce mild hypoglycemia (Heald et al, 1965;Langslow et al, 1970;Lepkovsky et al, 1967). Additionally, injected insulin results in an increase in the concentration of plasma free fatty acids in chickens, which is the opposite of what has been observed in mammals (Heald et al, 1965;Langslow et al, 1971;Lepkovsky et al, 1967). In addition to being relatively insensitive to glucose concentration, the chicken β-cell does not produce a sustained increase in insulin release in response to prolonged or repetitive stimuli, suggesting poor insulinogenic reserve (Naber and Hazelwood, 1977).…”

Habituation by the immature fowl in response to repeated injections of corticotrophin

“…In birds older than about 3 weeks the single injection usually brings about a hyperglycaemia and a decrease in the adrenal store of cholesterol (Siegel and Beane, 1961;Freeman et al, 1966;Freeman and Manning, 1977). The responses are similar if several injections are given over a period of a few days and persist for at least 24 h (Howard 392 B. M. FREEMAN, A. C. C. MANNING AND I. H. FLACK and Constable, 1958;Bell, 1961;Siegel, 1962a, b;Heald et al, 1965). If the treatment is prolonged to 3 weeks, however, the glycaemic, but not the cholesterol depletion, response is no longer detectable 24 h after the final injection (Freeman and Manning, 1975).…”