290
AUGUST EPPLE
known so far are rather similar in amino acid composition, but differ
markedly from mammalian insulin. Mammalian insulins, as well as insulins from other fish species, are usually hypoglycemic in fishes although
very high doses are required. The biological activity of teleost insulins
in mammalian test systems shows a considerable species specificity which
does not reflect their taxonomic relation. The action spectra of mammalian
and teleost insulins appear to be different. No data on nonsuppressible
insulinlike activity (cf. Pfoffenbarger et al., 1968) seem to be available
for fishes.
2. GLUCAGON
Glucagon was discovered as a hyperglycemic impurity of early preparations of mammalian insulin (Berthet, 1963); yet Geiling and de
Lawder (1930) were unable to demonstrate its presence in the insulin
preparations of Gadus morrhua and PoUachius virens. Mosca and associates (Mosca, 1959) obtained a hyperglycemic effect of islet extracts
from Scorpaenu scrofa only after inactivation of insulin by 0.1 N KOH.
Audy and Kerly (1952) found a glycogenolytic effect of islet extracts
from Lophius piscatorius in uitro; when compared to their yields from
mammalian pancreata, the fish glucagon must have been rather inefficient. Weitzel et al. (1953) did not observe any specific glucagon activity (as initial hyperglycemia) in various teleost insulins. Planas and
Lluch (19%) obtained a hyperglycemic factor from the Brockmann bodies of Thunnus thynnus. Glucagon from Cottus scorpius causes hyperglycemia in the fish, but not in the rabbit; and only high doses of ox
glucagon evoke hyperglycemia in Cottus scorpius ( Falkmer, 19f35a, 1966).
Likewise Wright (1958) observed a rather low sensitivity to the hyperglycemic action of mammalian glucagon in Lophius piscatorizrs. Young
and Chavin (1965) found a transient hyperglycemic response to mammalian glucagon in the goldfish, Carassius auratus. After injection of
mammalian glucagon, slight hyperglycemia was also seen in the elasmobranchs Raja erinucea (W. C. Grant, 1964) and Squulus acanthh, but
not in the holocephalian, Hydrolagus colliei (Patent, 1968).
Glucagon from Cottus scorpius showed only a faint binding to rabbit
antibodies against mammalian glucagon, while the same method failed
to detect glucagon in pancreas extracts of Squalus acanthh and islet
extracts of Myxine glutinosa (Falkmer, 1966).
In conclusion, glucagon appears to have a high biological and immunological species specificity.
There do not appear to be any reports on gastrointestinal glucagon
(Unger et al., 1968) in fishes.
AUGUST EPPLE
known so far are rather similar in amino acid composition, but differ
markedly from mammalian insulin. Mammalian insulins, as well as insulins from other fish species, are usually hypoglycemic in fishes although
very high doses are required. The biological activity of teleost insulins
in mammalian test systems shows a considerable species specificity which
does not reflect their taxonomic relation. The action spectra of mammalian
and teleost insulins appear to be different. No data on nonsuppressible
insulinlike activity (cf. Pfoffenbarger et al., 1968) seem to be available
for fishes.
2. GLUCAGON
Glucagon was discovered as a hyperglycemic impurity of early preparations of mammalian insulin (Berthet, 1963); yet Geiling and de
Lawder (1930) were unable to demonstrate its presence in the insulin
preparations of Gadus morrhua and PoUachius virens. Mosca and associates (Mosca, 1959) obtained a hyperglycemic effect of islet extracts
from Scorpaenu scrofa only after inactivation of insulin by 0.1 N KOH.
Audy and Kerly (1952) found a glycogenolytic effect of islet extracts
from Lophius piscatorius in uitro; when compared to their yields from
mammalian pancreata, the fish glucagon must have been rather inefficient. Weitzel et al. (1953) did not observe any specific glucagon activity (as initial hyperglycemia) in various teleost insulins. Planas and
Lluch (19%) obtained a hyperglycemic factor from the Brockmann bodies of Thunnus thynnus. Glucagon from Cottus scorpius causes hyperglycemia in the fish, but not in the rabbit; and only high doses of ox
glucagon evoke hyperglycemia in Cottus scorpius ( Falkmer, 19f35a, 1966).
Likewise Wright (1958) observed a rather low sensitivity to the hyperglycemic action of mammalian glucagon in Lophius piscatorizrs. Young
and Chavin (1965) found a transient hyperglycemic response to mammalian glucagon in the goldfish, Carassius auratus. After injection of
mammalian glucagon, slight hyperglycemia was also seen in the elasmobranchs Raja erinucea (W. C. Grant, 1964) and Squulus acanthh, but
not in the holocephalian, Hydrolagus colliei (Patent, 1968).
Glucagon from Cottus scorpius showed only a faint binding to rabbit
antibodies against mammalian glucagon, while the same method failed
to detect glucagon in pancreas extracts of Squalus acanthh and islet
extracts of Myxine glutinosa (Falkmer, 1966).
In conclusion, glucagon appears to have a high biological and immunological species specificity.
There do not appear to be any reports on gastrointestinal glucagon
(Unger et al., 1968) in fishes.