134
A. M. PERKS
B. The Nature of the Neurohypophysial Principles of the Elasmobranchs
Early work on the biological activities of the elasmobranch neurohypophysis gave inconclusive results, mainly because of the low levels of
activity which were present in the pituitary gland. Herring (1908a,b)
failed to find pressor effects or consistent changes of urine flow after the
injection of skate pituitary extracts into cats. However, he obtained an
oxytocic action on the isolated rat uterus after the addition of extracts
from the pituitary of Raia clauata (Herring, 1914). His most remarkable
observation was that of a rapid ejection of milk, after the intrajugular
injection of an extract of skate pituitary into a lactating cat (Herring,
1913). At the time, he did not recognize this milk-ejection effect as a
property of a neurohypophysial principle. In 1925, Hogben and de Beer
showed that skate pituitary extracts produced a weak oxytocic effect on
the isolated guinea pig uterus. Although Hogben (1925) found that the
extract caused a weak depressor effect when injected into a duck, he did
not emphasize that this was evidence for an elasmobranch oxytocinlike
principle. In 1936, Geiling and Le Messurier gave a brief report of “a
suggestion” of pressor activity, and an “inconclusive” antidiuretic effect
from extracts of the pituitaries of dogfish and skate (Squulus acanthias,
Raia sp.?) , However, in 1941, Heller ( 1941a) detected and assayed a low
level of antidiuretic activity in glands from European dogfish and
skate ( Scyliorhinus caniculus, Raia sp.? ) . Nevertheless, by 1950, Waring
and Landgrebe had failed to confirm the presence of either oxytocic
or vasopressor activities in glands taken from living elasmobranchs,
and they suggested that the earlier positive results were caused by
the presence of histamine. However, this suggestion was not in full
agreement with all the known facts. It was not supported by Herring’s
early observation of milk-ejection activity nor by his detection of oxytocic
effects on the isolated rat uterus, which was known to be insensitive to
histamine. It was made even less likely when Maetz et al. (1959) observed
both oxytocic and natriferic activity in extracts from the pituitaries of
Scyliorhinus caniculus and Hexanchus griseus.
The consensus of these different observations suggested to Perks,
Dodd and Dodd (1960; Perks, 1959) that the elasmobranchs might contain an oxytocinlike principle. For this reason they examined elasmobranch neurointermediate lobe extracts by a combination of different
biological assays, and determined the properties of the active agents by
the use of inhibitors known to destroy mammalian neurohypophysial
principles. They detected milk-ejection, oxytocic, and antidiuretic activities in extracts from Squalus acanthias, Scyliorhinus caniculus, Raia
A. M. PERKS
B. The Nature of the Neurohypophysial Principles of the Elasmobranchs
Early work on the biological activities of the elasmobranch neurohypophysis gave inconclusive results, mainly because of the low levels of
activity which were present in the pituitary gland. Herring (1908a,b)
failed to find pressor effects or consistent changes of urine flow after the
injection of skate pituitary extracts into cats. However, he obtained an
oxytocic action on the isolated rat uterus after the addition of extracts
from the pituitary of Raia clauata (Herring, 1914). His most remarkable
observation was that of a rapid ejection of milk, after the intrajugular
injection of an extract of skate pituitary into a lactating cat (Herring,
1913). At the time, he did not recognize this milk-ejection effect as a
property of a neurohypophysial principle. In 1925, Hogben and de Beer
showed that skate pituitary extracts produced a weak oxytocic effect on
the isolated guinea pig uterus. Although Hogben (1925) found that the
extract caused a weak depressor effect when injected into a duck, he did
not emphasize that this was evidence for an elasmobranch oxytocinlike
principle. In 1936, Geiling and Le Messurier gave a brief report of “a
suggestion” of pressor activity, and an “inconclusive” antidiuretic effect
from extracts of the pituitaries of dogfish and skate (Squulus acanthias,
Raia sp.?) , However, in 1941, Heller ( 1941a) detected and assayed a low
level of antidiuretic activity in glands from European dogfish and
skate ( Scyliorhinus caniculus, Raia sp.? ) . Nevertheless, by 1950, Waring
and Landgrebe had failed to confirm the presence of either oxytocic
or vasopressor activities in glands taken from living elasmobranchs,
and they suggested that the earlier positive results were caused by
the presence of histamine. However, this suggestion was not in full
agreement with all the known facts. It was not supported by Herring’s
early observation of milk-ejection activity nor by his detection of oxytocic
effects on the isolated rat uterus, which was known to be insensitive to
histamine. It was made even less likely when Maetz et al. (1959) observed
both oxytocic and natriferic activity in extracts from the pituitaries of
Scyliorhinus caniculus and Hexanchus griseus.
The consensus of these different observations suggested to Perks,
Dodd and Dodd (1960; Perks, 1959) that the elasmobranchs might contain an oxytocinlike principle. For this reason they examined elasmobranch neurointermediate lobe extracts by a combination of different
biological assays, and determined the properties of the active agents by
the use of inhibitors known to destroy mammalian neurohypophysial
principles. They detected milk-ejection, oxytocic, and antidiuretic activities in extracts from Squalus acanthias, Scyliorhinus caniculus, Raia