230
J. N. BALL
of GH in mammals (Evans et al., 1966; Pecile and Muller, 1968). Preliminary work by Enomoto (1964a) suggests that chronic treatment of intact
rainbow trout with beef GH caused growth and increased the crude
protein content of the carcass.
For elasmobranchs, Orias (1932) and Abramowitz et al. (1940) reported amelioration of the diabetes of pancreatectomized dogfish following hypophysectomy. This recalls the Houssay phenomenon in higher
vertebrates which hinges principally on the action of GH in inhibiting
peripheral glucose utilization (see Knobil and Sandler, 1963; Evans et al.,
1966). Thus in dogfish, as in tetrapods, GH appears to be diabetogenic.
Comparable studies on teleosts or other fishes have not been reported,
but GH injections elevated plasma glucose in intact Cottus (Matty,
1962); and in preliminary experiments, Enomoto (1964b) found that a
single injection of beef GH caused transient glucosuria, but no elevation
of blood glucose, which suggests a renal effect of the GH rather than an
action on tissue utilization of glucose. Despite some dissenting claims in
the earlier literature, it appears that fish pituitary extracts (Pickford,
1957) and purified fish GH (Wilhelmi, 1955) are not diabetogenic in
higher vertebrates and have no effect on rat cardiac glycogen (Wilhelmi,
1955). Purified fish GH also failed to stimulate nitrogen retention in the
rat (Wilhelmi, 1955), which is in line with its failure to promote growth
of rats (Section F).
E. Miscellaneous Effects of GH in Fishes
Some possible effects of GH on electrolyte metabolism have been
adumbrated in the literature, although in each case the data are only
suggestive and require extension. D. C. W. Smith (1956) found that GH
increased the tolerance of trout to high salinities, and Hoar (1W6) cites
results of J. E. McInerney as demonstrating changes in the salinity preference of young coho salmon after a long period of GH injections. These
two findings suggest a possible role for GH in the complex of physiological changes at smoltification in salmonids. Although GH had no marked
effects on plasma electrolytes in intact trout, it did increase the potassium
content of the muscles ( Chartier-Baraduc, 1959), an observation to be
placed alongside the extreme activation of the GH cells in eels kept in
deionized water (Olivereau, 1967; see Chapter by Ball and Baker, this
volume). It is possible that in the intact eel in deionized water an increased GH secretion opposes the movement of potassium from muscles
to plasma, a movement that is more marked in the absence of the pitui-
J. N. BALL
of GH in mammals (Evans et al., 1966; Pecile and Muller, 1968). Preliminary work by Enomoto (1964a) suggests that chronic treatment of intact
rainbow trout with beef GH caused growth and increased the crude
protein content of the carcass.
For elasmobranchs, Orias (1932) and Abramowitz et al. (1940) reported amelioration of the diabetes of pancreatectomized dogfish following hypophysectomy. This recalls the Houssay phenomenon in higher
vertebrates which hinges principally on the action of GH in inhibiting
peripheral glucose utilization (see Knobil and Sandler, 1963; Evans et al.,
1966). Thus in dogfish, as in tetrapods, GH appears to be diabetogenic.
Comparable studies on teleosts or other fishes have not been reported,
but GH injections elevated plasma glucose in intact Cottus (Matty,
1962); and in preliminary experiments, Enomoto (1964b) found that a
single injection of beef GH caused transient glucosuria, but no elevation
of blood glucose, which suggests a renal effect of the GH rather than an
action on tissue utilization of glucose. Despite some dissenting claims in
the earlier literature, it appears that fish pituitary extracts (Pickford,
1957) and purified fish GH (Wilhelmi, 1955) are not diabetogenic in
higher vertebrates and have no effect on rat cardiac glycogen (Wilhelmi,
1955). Purified fish GH also failed to stimulate nitrogen retention in the
rat (Wilhelmi, 1955), which is in line with its failure to promote growth
of rats (Section F).
E. Miscellaneous Effects of GH in Fishes
Some possible effects of GH on electrolyte metabolism have been
adumbrated in the literature, although in each case the data are only
suggestive and require extension. D. C. W. Smith (1956) found that GH
increased the tolerance of trout to high salinities, and Hoar (1W6) cites
results of J. E. McInerney as demonstrating changes in the salinity preference of young coho salmon after a long period of GH injections. These
two findings suggest a possible role for GH in the complex of physiological changes at smoltification in salmonids. Although GH had no marked
effects on plasma electrolytes in intact trout, it did increase the potassium
content of the muscles ( Chartier-Baraduc, 1959), an observation to be
placed alongside the extreme activation of the GH cells in eels kept in
deionized water (Olivereau, 1967; see Chapter by Ball and Baker, this
volume). It is possible that in the intact eel in deionized water an increased GH secretion opposes the movement of potassium from muscles
to plasma, a movement that is more marked in the absence of the pitui-