The relationship between total non-haem, ferritin and haemosiderin iron in larvae of Southern Hemisphere lampreys (Geotria australis andMordacia mordax)
Macey, D.J., Smalley, S.R., Potter, I.C. and Cake, M.H. (1985) The relationship between total non-haem, ferritin and haemosiderin iron in larvae of Southern Hemisphere lampreys (Geotria australis andMordacia mordax). Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology, 156 (2). pp. 269-276.
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The major iron binding protein (IBP) of larvalM. mordax has an estimated molecular weight (354,000), subunit molecular weight (18,000) and pI (5.1) identical to those recorded previously for larvalG. australis. The IBP in larvalG. australis has also been shown to be relatively heat stable and to react immunologically with antihorse spleen ferritin. The weight of total non-haem iron in the whole body, and both the ferritin and haemosiderin iron components, increased with increasing body weight in larvalG. australis. While the concentration of ferritin iron remained similar throughout larval life, the concentration of total non-haem iron and haemosiderin iron increased rapidly in animals up to a body weight of 0.1–0.2 g, but thereafter rose only slowly throughout the rest of larval life. This implies that any iron in excess of the amount required for the maintenance of a constant ferritin concentration is converted into haemosiderin iron, and that once non-haem iron has reached a particular concentration (c. 500–600 mgrg g–1), the rate of iron accumulation is greatly reduced. While the larvae of bothG. australis andM. mordax had very high plasma iron levels (>19,000 mgrg 100 ml–1), the former had significantly greater concentrations of iron in the whole body (702vs. 267 mgrg g–1) and more particularly in the nephric fold (7382vs. 224 mgrg g–1). A greater reservoir of non-haem iron could facilitate the maintenance of the large amounts of haem and erythrocytic ferritin present in this species as a result of an exceptionally high haemoglobin concentration and red blood cell number. The greater concentration of non-haem iron in the intestine ofM. mordax than ofG. australis (1338vs. 824 mgrg g–1), when considered in conjunction with histological studies, indicates thatMordacia mordax eliminates a larger amount of iron during the extrusion of its intestinal columnar cells.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Environmental and Life Sciences|
|Copyright:||© 1985 Springer-Verlag|
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