350
CHESTER JONES, CHAN, HENDERSON, AND BALL
for the full biological potency of the molecule (see Li, 1963; Evans et al.,
1966).
C. ACTH in Teleost Fishes
The presence of ACTH activity in the adenohypophyses of teleost
fishes is documented. Extracts from pituitary glands of the salmon,
Oncorhynchus keta (Rinfret and Hane, 1955), and the cod (Woodhead,
1960) gave positive responses in the adrenal ascorbic acid depletion bioassay in the rat. The cod material also maintained adrenal weight of
hypophysectomized rats and reduced thymus weight. Goldfish pituitaries
incubated in vitro released materials into the incubation medium which
stimulated in vitro steroidogenesis by the mouse adrenal gland (Purrot
and Sage, 1967).
Teleost adrenocortical tissue responds to exogenous ACTH of either
piscine or mammalian origin. In intact fish, injection of mammalian ACTH
causes hypertrophy of the adrenocortical cells with marked increases in
nuclear diameter and/or cell volume (Rasquin, 1951; Burden, 1956;
Chavin, 1956; Pickford and Atz, 1957; Basu et al., 1965; Hanke and
Chester Jones, 1966; Hanke et al., 1967). Hypophysectomy resulted in
adrenocortical regression which can be prevented by injection of mammalian ACTH (Burden, 1956; Chavin, 1956; Pickford and Atz, 1957;
Leloup-Hatey, 1964a; Basu et al., 1965), or the synthetic basic 24 amino
acid unit (D. K. 0. Chan et al., 1968b), or by extracts from fish pituitaries
(van Overbeeke and Ahsan, 1966). Ectopic pituitary transplants also
maintained some histological stimulation in the hypophysectomized
Poecilia latipinna ( Ball et al., 1965).
After hypophysectomy there was a marked reduction in circulating
17-hydroxycorticosteroids in Anguilla anguilla, and injection of mammalian ACTH increased the levels ( Leloup-Hatey, 1964a). In the rainbow trout also there was a decline in plasma cortisol concentration following hypophysectomy (Donaldson and McBride, 1967).
Stimulation of endogenous ACTH secretion by pharmacological inhibition of steroidogenesis thereby reducing the circulating level of adrenal
steroids has also been attempted. Amphenone B caused hypertrophy and
hyperplasia of the adrenocortical tissue of Betta splendens, Gasterosteus
aculeatus, and Lebistes reticularis (van Overbeeke, 1960). Similarly,
metopirone stimulated the adrenal cortex of Anguilla anguilla and Poecilia
latipinnu (Olivereau, 1965; Olivereau and Ball, 1963, 1964; Ball and
Olivereau, 1966). The effect of metopirone is mediated by enhancing
pituitary ACTH secretion as it is abolished by hypophysectomy (Ball and
Olivereau, 1966). Drugs such as reserpine, which induce release of ACTH,
CHESTER JONES, CHAN, HENDERSON, AND BALL
for the full biological potency of the molecule (see Li, 1963; Evans et al.,
1966).
C. ACTH in Teleost Fishes
The presence of ACTH activity in the adenohypophyses of teleost
fishes is documented. Extracts from pituitary glands of the salmon,
Oncorhynchus keta (Rinfret and Hane, 1955), and the cod (Woodhead,
1960) gave positive responses in the adrenal ascorbic acid depletion bioassay in the rat. The cod material also maintained adrenal weight of
hypophysectomized rats and reduced thymus weight. Goldfish pituitaries
incubated in vitro released materials into the incubation medium which
stimulated in vitro steroidogenesis by the mouse adrenal gland (Purrot
and Sage, 1967).
Teleost adrenocortical tissue responds to exogenous ACTH of either
piscine or mammalian origin. In intact fish, injection of mammalian ACTH
causes hypertrophy of the adrenocortical cells with marked increases in
nuclear diameter and/or cell volume (Rasquin, 1951; Burden, 1956;
Chavin, 1956; Pickford and Atz, 1957; Basu et al., 1965; Hanke and
Chester Jones, 1966; Hanke et al., 1967). Hypophysectomy resulted in
adrenocortical regression which can be prevented by injection of mammalian ACTH (Burden, 1956; Chavin, 1956; Pickford and Atz, 1957;
Leloup-Hatey, 1964a; Basu et al., 1965), or the synthetic basic 24 amino
acid unit (D. K. 0. Chan et al., 1968b), or by extracts from fish pituitaries
(van Overbeeke and Ahsan, 1966). Ectopic pituitary transplants also
maintained some histological stimulation in the hypophysectomized
Poecilia latipinna ( Ball et al., 1965).
After hypophysectomy there was a marked reduction in circulating
17-hydroxycorticosteroids in Anguilla anguilla, and injection of mammalian ACTH increased the levels ( Leloup-Hatey, 1964a). In the rainbow trout also there was a decline in plasma cortisol concentration following hypophysectomy (Donaldson and McBride, 1967).
Stimulation of endogenous ACTH secretion by pharmacological inhibition of steroidogenesis thereby reducing the circulating level of adrenal
steroids has also been attempted. Amphenone B caused hypertrophy and
hyperplasia of the adrenocortical tissue of Betta splendens, Gasterosteus
aculeatus, and Lebistes reticularis (van Overbeeke, 1960). Similarly,
metopirone stimulated the adrenal cortex of Anguilla anguilla and Poecilia
latipinnu (Olivereau, 1965; Olivereau and Ball, 1963, 1964; Ball and
Olivereau, 1966). The effect of metopirone is mediated by enhancing
pituitary ACTH secretion as it is abolished by hypophysectomy (Ball and
Olivereau, 1966). Drugs such as reserpine, which induce release of ACTH,