A comparative study on avian adrenocortical response to exogenous and endogenous corticotropin

Abstract

The transient effects of exogenous ACTH and unilateral adrenalectomy on the adrenal weight, histology, adrenal cholesterol and ascorbic acid were studied in several adult avian species. A single injection of ACTH produced a significant depression of adrenal ascorbic acid (AAA) in the pigeon (Columba Ziuia), the egret (BubuZcus ibis) and the myna (Acridotheres tristis). A fall in AAA was encountered in the unilaterally adrenalectomised pigeon and myna. A depletion of adrenal cholesterol induced by temporary ACTH treatment was noted in the pigeon, the egret and the myna; unilateral adrenalectomy produced a cholesterol depletion in the myna but not in the pigeon. Adrenal weight studies were not corroborative but there was a histological response of the interrend in various treatments.In mammals, the immediate response to systemic stress is manifested by adrenocortical hypertrophy and depletion of adrenal cholesterol and ascorbic acid. These adrenal responses have been studied in birds, but the results are often conflicting. Adrenal hypertrophy in the chick has been shown to accompany such stress stimuli as disease, muscular fatigue, reduced atmospheric pressure, and cold exposure (Hohn, '47; Garren and Schaf€ner, '56), increased population density (Siegel, '60), and increased social competition (Siegel and Siegel, '61). Contrarily, absence of adrenal hypertrophy in the chick in response to cold stress (Munday and BXane, '61) and single doses of ACTH has been noted (Dulin, '53; Huble, '58; Conner, '59). Flickinger ('59) also noted that dosages of ACTH that produce significant adrenal hypertrophy in laboratory mammals did not evoke such response in the Califomia quail. With chronic ACTH administration, however, a number of workers reported hypertrophy of bird adrenals (Bates et al., '40; Miller and Riddle, '42; Jailer and Boas, '50; Zarrow and Baldini, '52; Garren and Hill, '58; Brown et al., '58; Garren et al., '61).Siegel and Beane ('61) observed that, although adrenal hypertrophy was not produced by single ACTH injections, there was adrenal cholesterol depletion, hyperglycemia and hypercholesteremia. Siegel ('62) also concluded that age and ACTH treat-J. EXP. ZOOL., 165: 301-308. ment together influenced the adrenal cholesterol level in the chicken. A single ACTH injection was found to lower total adrenal cholesterol in the chicken 12 hours following administration (Koji and Glick, '64), but not within 1-4 hours of ACTH or cold treatment (Elton et al., '59). A bigger controversy remains with respect to experimental ascorbic acid depletion from avian adrenals, which is a common response to mammalian stress. The failure of parasitic infection, ACTH, epinephrine and cold to influence the adrenal ascorbic acid in the chick, quail or duckling has been reported (Josephson et al., '49; Jailer and Boas, '50; Zarrow and Zarrow, '50; Zarrow and Baldini, '52; Howard and Constable, '58; Elton et al., '59). Recently corticotropin-induced ascorbic acid depletion has been reported in one-year old laying hens, moltin...

Sex differences in glucocorticoid responses to shipping stress in Pekin ducks

“…Others ( Siegel and Siegel, 1966 ; Siegel, 1968 ) showed differences in responsiveness to ACTH on corticosterone release and other physiological factors influenced by strain of chicken as well as age. Similar observations have been made in the pigeon, egret, and myna ( Bhattacharyya et al, 1967 ). Siegel reported similar changes in blood cell counts in chickens treated with ACTH or cortisol ( Siegel, 1968 ).…”