360
CHESTER JONES, CHAN, HENDERSON, AND BALL
result from a change in the ionized fraction, although later the protein
binding of calcium increased and the ionized calcium concentration
quickly returned to normal (D. K. 0. Chan and Chester Jones, 1968;
Table VIII). In these studies no regeneration of corpuscles was observed,
so that secondary regulatory mechanisms must come into play after prolonged absence of the corpuscles.
The kidney appears to be a major. target organ upon which the
secretion( s) of the corpuscles of Stannius act. Removal of the corpuscles
of Stannius did not affect the sodium transporting systems in the gills of
either freshwater (Henderson and Chester Jones, 1967) or seawater
(Mayer and Maetz, 1967) eels. There were however marked changes in
renal function. In the freshwater eel, urinary calcium and magnesium
excretion gradually declined after removal of the glands and was sustained for approximately 2 weeks (the maximum observation period).
By the end of the first week after surgery urine production, in&
clearance, and urinary sodium and potassium were unaffected. Regrafting of
corpuscles back into the experimental fish 1 week after the initial operation readily elevated urinary calcium excretion. A similar effect was also
elicited by slow intravenous infusion of saline extracts of the glands
(D. K. 0. Chan et al., 1969).
In small doses (less than one gland per kilogram of body weight)
intravenous injections of extracts of the corpuscles of Stannius caused a
transient decline in inulin clearance, while in higher doses (pressor)
there was an initial drop in inulin clearance followed by an “overshoot” and
consequent increase in urine flow (Chester Jones et al., 1969a). The
vascular response and the changes in inulin clearance may be directly
related, and possibly the corpuscle extracts cause an intermittent constriction of renal arterioles (Chester Jones et al., 1969b).
From these studies it is clear that the secretion( s) of the corpuscles
of Stannius performs a role quite distinct from those of the adrenal cortex.
Both systems may obviously act upon the same target organ such as the
kidney. In their respective roles in the maintenance of electrolyte homeostasis the secretions of the corpuscles of Stannius and the adrenal cortex
supplement each other. Thus in adrenalectomized or hypophysectomized
freshwater eels, in which there is an hypocalcemia, removal of the corpuscles of Stannius still evoked the hypercalcemic response. It has been
suggested that mobilization of internal calcium pools following removal
of the corpuscles of Stannius, and the subsequent renal retention of
calcium, requires a functional pituitary-adrenocortical axis (D. K. 0.
Chan, 1968).
The picture is further complicated by the fact that removal of the
corpuscles of Stannius abolishes the hypocalcemic-hyperphosphatemic
CHESTER JONES, CHAN, HENDERSON, AND BALL
result from a change in the ionized fraction, although later the protein
binding of calcium increased and the ionized calcium concentration
quickly returned to normal (D. K. 0. Chan and Chester Jones, 1968;
Table VIII). In these studies no regeneration of corpuscles was observed,
so that secondary regulatory mechanisms must come into play after prolonged absence of the corpuscles.
The kidney appears to be a major. target organ upon which the
secretion( s) of the corpuscles of Stannius act. Removal of the corpuscles
of Stannius did not affect the sodium transporting systems in the gills of
either freshwater (Henderson and Chester Jones, 1967) or seawater
(Mayer and Maetz, 1967) eels. There were however marked changes in
renal function. In the freshwater eel, urinary calcium and magnesium
excretion gradually declined after removal of the glands and was sustained for approximately 2 weeks (the maximum observation period).
By the end of the first week after surgery urine production, in&
clearance, and urinary sodium and potassium were unaffected. Regrafting of
corpuscles back into the experimental fish 1 week after the initial operation readily elevated urinary calcium excretion. A similar effect was also
elicited by slow intravenous infusion of saline extracts of the glands
(D. K. 0. Chan et al., 1969).
In small doses (less than one gland per kilogram of body weight)
intravenous injections of extracts of the corpuscles of Stannius caused a
transient decline in inulin clearance, while in higher doses (pressor)
there was an initial drop in inulin clearance followed by an “overshoot” and
consequent increase in urine flow (Chester Jones et al., 1969a). The
vascular response and the changes in inulin clearance may be directly
related, and possibly the corpuscle extracts cause an intermittent constriction of renal arterioles (Chester Jones et al., 1969b).
From these studies it is clear that the secretion( s) of the corpuscles
of Stannius performs a role quite distinct from those of the adrenal cortex.
Both systems may obviously act upon the same target organ such as the
kidney. In their respective roles in the maintenance of electrolyte homeostasis the secretions of the corpuscles of Stannius and the adrenal cortex
supplement each other. Thus in adrenalectomized or hypophysectomized
freshwater eels, in which there is an hypocalcemia, removal of the corpuscles of Stannius still evoked the hypercalcemic response. It has been
suggested that mobilization of internal calcium pools following removal
of the corpuscles of Stannius, and the subsequent renal retention of
calcium, requires a functional pituitary-adrenocortical axis (D. K. 0.
Chan, 1968).
The picture is further complicated by the fact that removal of the
corpuscles of Stannius abolishes the hypocalcemic-hyperphosphatemic