120
A. M. PERI(s
no more than 0.13 mU/gland. Although it is possible that the reagent was
partly expended on extraneous materials in so crude an extract, it is
clear that the hagfish pituitary contains only traces of an oxytocic agent.
The detection of frog water balance activity, together with oxytocic and
natriferic effects, suggests the possibility that arginine vasotocin is present
in the hagfish, as well as in the lampreys, but the present evidence is
inadequate for anything more than speculation.
2. PETROMYZONIFORMES
The neurohypophysial principles of the lampreys have received more
attention than those of the hagfish. Herring (1913) showed that extracts
from Petromyzon fluviatilis could cause a weak antidiuretic effect in the
cat. These early studies were extended by Lanzing in 1954, when he detected frog water-balance and oxytocic activities in Lampetra fluviatilis.
However, it was doubtful whether the agent which stimulated the guinea
pig uterus was a true neurohypophysial peptide, since it was resistant to
sodium hydroxide inactivation. In 1955, W. H. Sawyer was able to demonstrate that pituitaries from Petromyzon marinus contained oxytocic and
vasopressor activities which were labile to sodium hydroxide treatment,
and, in a series of studies carried out by W. H. Sawyer et al. (1959,
1960, 1961), milk-ejection, antidiuretic, frog bladder and hen oviduct
stimulating actions were added to the properties of the extracts. Careful
quantitative comparisons of these activities suggested that the extracts
contained arginine vasotocin, a molecule which shared the ring structure
of oxytocin with the terminal side chain of arginine vasopressin (Table
I). This peptide might well serve as a potential “primitive” neurohypophysial principle ( W. H. Sawyer et al., 1961). Purification of Petromyzon marinus extracts by gel filtration and the use of carboxymethyl cellulose columns yielded an active eluate with pharmacological properties
similar to arginine vasotocin. A small “notch in the eluted activity peak
left some slight possibility that two similar peptides could coexist in the
extracts ( W. H. Sawyer, 1965b). The purification procedure did not
separate any oxytocinlike neutral peptide. However, it is possible that
small quantities of a neutral peptide could have escaped detection during
pharmacological studies (W. H. Sawyer, 1961 ), and these might have
been lost during the prolonged storage of the extract prior to purification.
In essentially similar pharmacological studies on Larnpetru fluviatilis,
Follett and Heller (1964a) showed that oxytocic, vasopressor, and natriferic activities were also in agreement with the presence of arginine
vasotocin. Paper chromatography in butanol-acetic acid-water, 4: 1 : 5,
showed that the major activity peak ran with an R, value of 0.25-0.35,
A. M. PERI(s
no more than 0.13 mU/gland. Although it is possible that the reagent was
partly expended on extraneous materials in so crude an extract, it is
clear that the hagfish pituitary contains only traces of an oxytocic agent.
The detection of frog water balance activity, together with oxytocic and
natriferic effects, suggests the possibility that arginine vasotocin is present
in the hagfish, as well as in the lampreys, but the present evidence is
inadequate for anything more than speculation.
2. PETROMYZONIFORMES
The neurohypophysial principles of the lampreys have received more
attention than those of the hagfish. Herring (1913) showed that extracts
from Petromyzon fluviatilis could cause a weak antidiuretic effect in the
cat. These early studies were extended by Lanzing in 1954, when he detected frog water-balance and oxytocic activities in Lampetra fluviatilis.
However, it was doubtful whether the agent which stimulated the guinea
pig uterus was a true neurohypophysial peptide, since it was resistant to
sodium hydroxide inactivation. In 1955, W. H. Sawyer was able to demonstrate that pituitaries from Petromyzon marinus contained oxytocic and
vasopressor activities which were labile to sodium hydroxide treatment,
and, in a series of studies carried out by W. H. Sawyer et al. (1959,
1960, 1961), milk-ejection, antidiuretic, frog bladder and hen oviduct
stimulating actions were added to the properties of the extracts. Careful
quantitative comparisons of these activities suggested that the extracts
contained arginine vasotocin, a molecule which shared the ring structure
of oxytocin with the terminal side chain of arginine vasopressin (Table
I). This peptide might well serve as a potential “primitive” neurohypophysial principle ( W. H. Sawyer et al., 1961). Purification of Petromyzon marinus extracts by gel filtration and the use of carboxymethyl cellulose columns yielded an active eluate with pharmacological properties
similar to arginine vasotocin. A small “notch in the eluted activity peak
left some slight possibility that two similar peptides could coexist in the
extracts ( W. H. Sawyer, 1965b). The purification procedure did not
separate any oxytocinlike neutral peptide. However, it is possible that
small quantities of a neutral peptide could have escaped detection during
pharmacological studies (W. H. Sawyer, 1961 ), and these might have
been lost during the prolonged storage of the extract prior to purification.
In essentially similar pharmacological studies on Larnpetru fluviatilis,
Follett and Heller (1964a) showed that oxytocic, vasopressor, and natriferic activities were also in agreement with the presence of arginine
vasotocin. Paper chromatography in butanol-acetic acid-water, 4: 1 : 5,
showed that the major activity peak ran with an R, value of 0.25-0.35,