328
CHESTER JONES, CHAN, HENDERSON, AND BALL
siderable interest. Sandor and his co-workers (1966, 1967) failed to
demonstrate the capacity of adrenocortical tissue plus head kidney of the
eel, Anguillu anguilla L., to synthesize aldosterone. It was thus regarded
as possible that aldosterone arose in the proto-amphibia, concomitant with
the conquest of a terrestrial habitat. However, the demonstration by
Truscott and Idler (1968a) that similar tissues in the herring will form
aldosterone from added corticosterone has reopened the question. It has
yet to be determined that aldosterone occurs normally as a functional hormone in cyclostomes, teleosts, and elasmobranchs. This hormone would
be of considerable significance in the control of electrolyte movements as
has been shown for the mammalian kidney and the skin and urinary bladder of anuran amphibians.
In the hagfish, Polidrema stouti and Myxine glutinosa, the principal
steroids isolated were corticosterone and cortisol ( Chester Jones and
Phillips, 1960; Phillips et al., 1962). Aldosterone was not detected by the
methods employed.
Cortisol and corticosterone have been extracted from the peripheral
plasma of elasmobranch species (Phillips, 1959; Chester Jones and
Phillips, 1960). Recently, studies by Idler and Truscott (1966) demonstrated that the principal adrenal steroid in this class of fish is la-hydroxycorticosterone. Corticosterone was present in very small amounts in these
same studies.
A summary of the data in the literature on the level of adrenocorticosteroids in fish blood is given in Table I. It must be cautioned that
the reported levels have been obtained over a period of a decade, which
has manifested an explosion of research activities and significant improvements in steroid analysis made. Modern techniques tend to give values
lower than those previously reported. Nevertheless, it is clear that the
normal physiological range of adrenocorticosteroids in blood is in the
order of micrograms per 100 milliliters of plasma. This will have an important bearing in physiological experiments.
B. Biogenesis of Adrenocorticosteroids
Another valuable tool in the study of the type of hormone secreted
by different species is to study the ability of the adrenal cortex to synthesize steroids in vitro. Briefly, the method involves placing sliced,
minced, or chopped adrenal cortices in an incubation medium consisting
of a Ringer’s solution of controlled pH and temperature, supplied with
metabolic substrates and perhaps enzyme cofactors. To these are added
nonradioactive or radioactively labeled ( tritium or carbon-14) hormone
CHESTER JONES, CHAN, HENDERSON, AND BALL
siderable interest. Sandor and his co-workers (1966, 1967) failed to
demonstrate the capacity of adrenocortical tissue plus head kidney of the
eel, Anguillu anguilla L., to synthesize aldosterone. It was thus regarded
as possible that aldosterone arose in the proto-amphibia, concomitant with
the conquest of a terrestrial habitat. However, the demonstration by
Truscott and Idler (1968a) that similar tissues in the herring will form
aldosterone from added corticosterone has reopened the question. It has
yet to be determined that aldosterone occurs normally as a functional hormone in cyclostomes, teleosts, and elasmobranchs. This hormone would
be of considerable significance in the control of electrolyte movements as
has been shown for the mammalian kidney and the skin and urinary bladder of anuran amphibians.
In the hagfish, Polidrema stouti and Myxine glutinosa, the principal
steroids isolated were corticosterone and cortisol ( Chester Jones and
Phillips, 1960; Phillips et al., 1962). Aldosterone was not detected by the
methods employed.
Cortisol and corticosterone have been extracted from the peripheral
plasma of elasmobranch species (Phillips, 1959; Chester Jones and
Phillips, 1960). Recently, studies by Idler and Truscott (1966) demonstrated that the principal adrenal steroid in this class of fish is la-hydroxycorticosterone. Corticosterone was present in very small amounts in these
same studies.
A summary of the data in the literature on the level of adrenocorticosteroids in fish blood is given in Table I. It must be cautioned that
the reported levels have been obtained over a period of a decade, which
has manifested an explosion of research activities and significant improvements in steroid analysis made. Modern techniques tend to give values
lower than those previously reported. Nevertheless, it is clear that the
normal physiological range of adrenocorticosteroids in blood is in the
order of micrograms per 100 milliliters of plasma. This will have an important bearing in physiological experiments.
B. Biogenesis of Adrenocorticosteroids
Another valuable tool in the study of the type of hormone secreted
by different species is to study the ability of the adrenal cortex to synthesize steroids in vitro. Briefly, the method involves placing sliced,
minced, or chopped adrenal cortices in an incubation medium consisting
of a Ringer’s solution of controlled pH and temperature, supplied with
metabolic substrates and perhaps enzyme cofactors. To these are added
nonradioactive or radioactively labeled ( tritium or carbon-14) hormone