148
A. M. PERKS
teleosts. The surface of each neural process is close to a rich capillary
plexus. Some vessels pass between the neurointermediate tissue and
other regions of the adenohypophysis, and they form a route by which
neurosecretory materials might reach other areas of the pituitary (above
species, Kerr, 1968). However, it is probable that neurohypophysial peptides could pass on into the general circulation.
B. The Nature of the Neurohypophysial Principles
of the Brachiopterygians
Studies of crude and partially purified extracts from the pituitary of
Polyptew senegalis have shown the presence of oxytocic, avian depressor, guinea pig milk-ejection, frog bladder, and natriferic activities ( W. H.
Sawyer and Van Dyke, 1963a,b; Follett and Heller, 1964b; W. H. Sawyer,
1964, l968a). The high potency in promoting water reabsorption from the
frog bladder, and the level of natriferic activity, indicate the presence of
arginine vasotocin. In addition, a neutral, oxytocinlike peptide has been
separated by both paper chromatography and purification on carboxymethyl cellulose columns ( W. H. Sawyer, 1968a). Early pharmacological
data suggested that this neutral peptide was 8 Ile oxytocin, or a mixture
of this peptide with 4 Ser, 8 Ile oxytocin (W. H. Sawyer, 1964, 1968a).
However, column partition chromatography, together with a direct comparison of the neutral peptide with synthetic 8 Ile oxytocin and synthetic
4 Ser, 8 Ile oxytocin, has strongly suggested that Polypterus senegalis contains 4 Ser, 8 Ile oxytocin ( W. H. Sawyer, 1969). At present there is no
chemical Confirmation of the structure of the peptides of this species.
However, the pharmacological data suggest the presence of arginine
vasotocin and 4 Ser, 8 Ile oxytocin in the primitive brachiopterygians,
and this indicates that the pattern of the neurohypophysial peptides was
set early in the evolution of the bony fish.
C. The Actions of Neurohypophysial Principles
in the Brachiopterygians
There is no direct information on the actions of arginine vasotocin
or of 4 Ser, 8 Ile oxytocin in this group. It is only possible to point out that
the anatomical relationships of the pituitary are compatible with their
possible importance in the control of the adenohypophysis. They could
also reach the systemic circulation, and affect tissues throughout the body.
A. M. PERKS
teleosts. The surface of each neural process is close to a rich capillary
plexus. Some vessels pass between the neurointermediate tissue and
other regions of the adenohypophysis, and they form a route by which
neurosecretory materials might reach other areas of the pituitary (above
species, Kerr, 1968). However, it is probable that neurohypophysial peptides could pass on into the general circulation.
B. The Nature of the Neurohypophysial Principles
of the Brachiopterygians
Studies of crude and partially purified extracts from the pituitary of
Polyptew senegalis have shown the presence of oxytocic, avian depressor, guinea pig milk-ejection, frog bladder, and natriferic activities ( W. H.
Sawyer and Van Dyke, 1963a,b; Follett and Heller, 1964b; W. H. Sawyer,
1964, l968a). The high potency in promoting water reabsorption from the
frog bladder, and the level of natriferic activity, indicate the presence of
arginine vasotocin. In addition, a neutral, oxytocinlike peptide has been
separated by both paper chromatography and purification on carboxymethyl cellulose columns ( W. H. Sawyer, 1968a). Early pharmacological
data suggested that this neutral peptide was 8 Ile oxytocin, or a mixture
of this peptide with 4 Ser, 8 Ile oxytocin (W. H. Sawyer, 1964, 1968a).
However, column partition chromatography, together with a direct comparison of the neutral peptide with synthetic 8 Ile oxytocin and synthetic
4 Ser, 8 Ile oxytocin, has strongly suggested that Polypterus senegalis contains 4 Ser, 8 Ile oxytocin ( W. H. Sawyer, 1969). At present there is no
chemical Confirmation of the structure of the peptides of this species.
However, the pharmacological data suggest the presence of arginine
vasotocin and 4 Ser, 8 Ile oxytocin in the primitive brachiopterygians,
and this indicates that the pattern of the neurohypophysial peptides was
set early in the evolution of the bony fish.
C. The Actions of Neurohypophysial Principles
in the Brachiopterygians
There is no direct information on the actions of arginine vasotocin
or of 4 Ser, 8 Ile oxytocin in this group. It is only possible to point out that
the anatomical relationships of the pituitary are compatible with their
possible importance in the control of the adenohypophysis. They could
also reach the systemic circulation, and affect tissues throughout the body.