containing melanomacrophages are normally present in the
interstitial renal tissue. Their number typically increases
with age and with disease conditions. The kidney also
contains endocrine elements such as chromaffine cells
located in the wall of the posterior cardinal vein that release
adrenaline and noradrenaline into the circulation, and interrenal tissue which in most teleosts is located around major
veins (Fig. 2.49).
Ventral to the oesophagus in the septum transversum
separating the heart from the abdominal cavity is the small
endocrine ultimobranchial gland, derived from the pharynx.
This secretes the hormone calcitonin which lowers serum
calcium levels and acts with hypocalcin (secreted by the
corpuscles of Stannius) to regulate calcium metabolism.
The epiphysis projecting from the epithalamus produces
melatonin.
Fig. 2.46 Thymus of Atlantic salmon parr
Fig. 2.47 Corpuscle of Stannius near the margin of the kidney in
brook trout
Fig. 2.48 Corpuscle of Stannius (left) within the kidney of Atlantic
salmon. Bar ¼ 100 μm
Fig. 2.49 Adrenal cortical tissue in head kidney from rainbow trout.
Note melanomacrophages in renal interstitium. Medium power
Fig. 2.45 Thyroid follicles located near the ventral aorta of an Atlantic
salmon parr
2.9 Endocrine System
23
interstitial renal tissue. Their number typically increases
with age and with disease conditions. The kidney also
contains endocrine elements such as chromaffine cells
located in the wall of the posterior cardinal vein that release
adrenaline and noradrenaline into the circulation, and interrenal tissue which in most teleosts is located around major
veins (Fig. 2.49).
Ventral to the oesophagus in the septum transversum
separating the heart from the abdominal cavity is the small
endocrine ultimobranchial gland, derived from the pharynx.
This secretes the hormone calcitonin which lowers serum
calcium levels and acts with hypocalcin (secreted by the
corpuscles of Stannius) to regulate calcium metabolism.
The epiphysis projecting from the epithalamus produces
melatonin.
Fig. 2.46 Thymus of Atlantic salmon parr
Fig. 2.47 Corpuscle of Stannius near the margin of the kidney in
brook trout
Fig. 2.48 Corpuscle of Stannius (left) within the kidney of Atlantic
salmon. Bar ¼ 100 μm
Fig. 2.49 Adrenal cortical tissue in head kidney from rainbow trout.
Note melanomacrophages in renal interstitium. Medium power
Fig. 2.45 Thyroid follicles located near the ventral aorta of an Atlantic
salmon parr
2.9 Endocrine System
23