364
CHESTER JONES, CHAN, HENDERSON, AND BALL
VIII. CONCLUSIONS
It has been the purpose of this chapter to consider the role of the
adrenocortical secretions in the physiology of fishes. Much of the data
have been derived from a limited number of species, and how far one can
extrapolate from these to whole classes remains to be examined.
In studying the endocrinology of fishes, it is well to recall that the
aquatic environment (particularly the marine habitat) does not exhibit
the extreme vagaries encountered in the terrestrial existence. Situations
where dehydrating or hyperhydrating circumstances suddenly arise, or
where there are rapid and extreme changes of temperature, rarely appear.
The migrating euryhaline fishes do of course encounter such variations,
but these species are exceptions rather than the rule.
The one really variable feature in the biology of fishes is the availability of food. Metabolic and endocrine mechanisms to accommodate
sudden engorgement in the cases of some fishes, and the slow planktonic
continuous feeding of others, and even the periodic cessation of feeding
in still others have been little studied. The metabolic role of corticosteroids and their secretory rates would be most informative in these extremes.
Much has still to be understood about the control of adrenal cortical
function both with respect to the metabolic and to electrolyte influences.
To date it would seem that the steroids are involved in regulating both
these parameters, although the delicate maintenance of homeostasis would
seem to merit further attention in many more species.
REFERENCES
Arai, R., and Tamaoki, B. (1967). Biosynthesis In uitro of 18-hydroxy-11-deoxycorticosterone by the interrenal tissue of the rainbow trout. 1. Endocrinol. 39,
453-154.
Aull, F. (1986). Absorption of fluid from isolated intestine of the toadfish, Opsanus
tau. Comp. Biochem. Physiol. 17,867-870.
Ball, J . N. ( 1968). Unpublished observations.
Ball, J. N., and Ensor, D. M. ( 1967). Specific action of prolactin on plasma sodium
levels in hypophysectomised Poecilfa latipinno (Teleostei). Gen. Comp. Endocrinol. 8, 432-440.
Ball, J. N., and Ensor, D. M. (1968). Aspects of the action of prolactin on sodium
metabolism in cyprinodont fishes. In “La specificit6 zoologique des hormones
hypophysaires et de leurs activid.” Colloq. Intern. Centre Natl. Rech. Sci. (Paris)
luly, 1968.
Ball, J. N., and Olivereau, M. (1966). Experimental identification of ACTH cells in
the pituitary of two teleosts, Poen’lia latipinnu and AnguiUa anguilk correlated
changes in the interrenal and in the pars distalis resulting from administration of
metopirone (SU 4885). Gen. Comp. Endocrinol. 6, 5-18.
CHESTER JONES, CHAN, HENDERSON, AND BALL
VIII. CONCLUSIONS
It has been the purpose of this chapter to consider the role of the
adrenocortical secretions in the physiology of fishes. Much of the data
have been derived from a limited number of species, and how far one can
extrapolate from these to whole classes remains to be examined.
In studying the endocrinology of fishes, it is well to recall that the
aquatic environment (particularly the marine habitat) does not exhibit
the extreme vagaries encountered in the terrestrial existence. Situations
where dehydrating or hyperhydrating circumstances suddenly arise, or
where there are rapid and extreme changes of temperature, rarely appear.
The migrating euryhaline fishes do of course encounter such variations,
but these species are exceptions rather than the rule.
The one really variable feature in the biology of fishes is the availability of food. Metabolic and endocrine mechanisms to accommodate
sudden engorgement in the cases of some fishes, and the slow planktonic
continuous feeding of others, and even the periodic cessation of feeding
in still others have been little studied. The metabolic role of corticosteroids and their secretory rates would be most informative in these extremes.
Much has still to be understood about the control of adrenal cortical
function both with respect to the metabolic and to electrolyte influences.
To date it would seem that the steroids are involved in regulating both
these parameters, although the delicate maintenance of homeostasis would
seem to merit further attention in many more species.
REFERENCES
Arai, R., and Tamaoki, B. (1967). Biosynthesis In uitro of 18-hydroxy-11-deoxycorticosterone by the interrenal tissue of the rainbow trout. 1. Endocrinol. 39,
453-154.
Aull, F. (1986). Absorption of fluid from isolated intestine of the toadfish, Opsanus
tau. Comp. Biochem. Physiol. 17,867-870.
Ball, J . N. ( 1968). Unpublished observations.
Ball, J. N., and Ensor, D. M. ( 1967). Specific action of prolactin on plasma sodium
levels in hypophysectomised Poecilfa latipinno (Teleostei). Gen. Comp. Endocrinol. 8, 432-440.
Ball, J. N., and Ensor, D. M. (1968). Aspects of the action of prolactin on sodium
metabolism in cyprinodont fishes. In “La specificit6 zoologique des hormones
hypophysaires et de leurs activid.” Colloq. Intern. Centre Natl. Rech. Sci. (Paris)
luly, 1968.
Ball, J. N., and Olivereau, M. (1966). Experimental identification of ACTH cells in
the pituitary of two teleosts, Poen’lia latipinnu and AnguiUa anguilk correlated
changes in the interrenal and in the pars distalis resulting from administration of
metopirone (SU 4885). Gen. Comp. Endocrinol. 6, 5-18.