346
CHESTER JONES, CHAN, HENDERSON, AND BALL
similar studies in mammals. It is not considered worthwhile in our present
state of knowledge to embark upon such a discussion.
D. Protein and Carbohydrate Metabolism
Evidence of the metabolic role of corticosteroids in fishes is gradually
emerging. The pattern, except for minor variations, conforms with that
established for other vertebrates. Experimental manipulations such as
hypophysectomy, adrenalectomy, injections of adrenal steroids, adrenal
steroid blockers, or ACTH have demonstrated that corticosteroids of the
cortisol type promote gluconeogenesis.
A high level of circulating corticosteroids is associated with the nonfeeding stages of the life history of some species. Thus in Oncorhynchus,
601% of the body protein is catabolized during the migration-spawning
phase (Idler and Clemens, 1959), and this is associated with a sixfold increase in plasma corticosteroids (Idler et al., 1959a,b) and an elevation
of liver glycogen (Chang and Idler, 1960). It appears that the hyperadrenocortical state is in some way associated with an internal rearrangement of tissue leading to a fall in muscle mass and an increase in size of
gonad (0. H. Robertson et al., 1961a, 1963). In various teleosts, increased
plasma corticosteroid levels have been shown to accompany extreme
locomotor activity ( Leloup-Hatey, 1958, 1960; Fontaine and LeloupHatey, 1960; Fagerlund, 1967).
Cortisol-like hormones have been implicated either directly or indirectly with the breakdown of selected tissues when the animal has to
maintain itself independently of its environment. The major catabolic
action seems to be on parietal muscle; the resultant amino acids may then
be used for the synthesis of new tissues elsewhere in the body (0. H.
Robertson et al., 1961a,b, 1963) or may enter gluconeogenesis to form
liver glycogen, as suggested by the data reviewed above.
Administration of cortisol or ACTH to teleosts usually yields evidence
of protein catabolism or growth inhibition; thus, in hypophysectomized
Poecilia latipinna, cortisol or ACTH increases weight loss, exaggerates
shrinkage in length, and impedes regeneration of the amputated caudal
fin (Ball, 1968; Ball and Ensor, 1968). Correspondingly, in various teleosts, increase in blood glucose or liver glycogen content follows administration of ACTH or corticosteroids (Nace, 1955; 0. H. Robertson et al.,
1963; Kumar et al., 1966; Oguri and Nace, 1966). Together with other
data (Hatey, 1951a,b; Bentley and Follet, 1965; Falkmer and Matty,
1966; Storer, 1967; Butler, 1968), these findings demonstrate that cortisoltype steroids promote gluconeogenesis in fishes.
CHESTER JONES, CHAN, HENDERSON, AND BALL
similar studies in mammals. It is not considered worthwhile in our present
state of knowledge to embark upon such a discussion.
D. Protein and Carbohydrate Metabolism
Evidence of the metabolic role of corticosteroids in fishes is gradually
emerging. The pattern, except for minor variations, conforms with that
established for other vertebrates. Experimental manipulations such as
hypophysectomy, adrenalectomy, injections of adrenal steroids, adrenal
steroid blockers, or ACTH have demonstrated that corticosteroids of the
cortisol type promote gluconeogenesis.
A high level of circulating corticosteroids is associated with the nonfeeding stages of the life history of some species. Thus in Oncorhynchus,
601% of the body protein is catabolized during the migration-spawning
phase (Idler and Clemens, 1959), and this is associated with a sixfold increase in plasma corticosteroids (Idler et al., 1959a,b) and an elevation
of liver glycogen (Chang and Idler, 1960). It appears that the hyperadrenocortical state is in some way associated with an internal rearrangement of tissue leading to a fall in muscle mass and an increase in size of
gonad (0. H. Robertson et al., 1961a, 1963). In various teleosts, increased
plasma corticosteroid levels have been shown to accompany extreme
locomotor activity ( Leloup-Hatey, 1958, 1960; Fontaine and LeloupHatey, 1960; Fagerlund, 1967).
Cortisol-like hormones have been implicated either directly or indirectly with the breakdown of selected tissues when the animal has to
maintain itself independently of its environment. The major catabolic
action seems to be on parietal muscle; the resultant amino acids may then
be used for the synthesis of new tissues elsewhere in the body (0. H.
Robertson et al., 1961a,b, 1963) or may enter gluconeogenesis to form
liver glycogen, as suggested by the data reviewed above.
Administration of cortisol or ACTH to teleosts usually yields evidence
of protein catabolism or growth inhibition; thus, in hypophysectomized
Poecilia latipinna, cortisol or ACTH increases weight loss, exaggerates
shrinkage in length, and impedes regeneration of the amputated caudal
fin (Ball, 1968; Ball and Ensor, 1968). Correspondingly, in various teleosts, increase in blood glucose or liver glycogen content follows administration of ACTH or corticosteroids (Nace, 1955; 0. H. Robertson et al.,
1963; Kumar et al., 1966; Oguri and Nace, 1966). Together with other
data (Hatey, 1951a,b; Bentley and Follet, 1965; Falkmer and Matty,
1966; Storer, 1967; Butler, 1968), these findings demonstrate that cortisoltype steroids promote gluconeogenesis in fishes.