75
reductase (Vallee,
1957).
The metabolism of the retina,
measured by oxygen consumption and carbon dioxide production,
is similar to that of the brain,
(Krause,
1934).
and not of other tissues
In a discussion of the stability of the
cerebral respiratory rate, McIlwain,
(1955) emphasized the
reciprocity of blood flow and the arterial-venous difference
in oxygen tension.
the other,
A rise in one is accompanied by a fall in
enabling the maintenance of relative stability in
the cerebral respiratory rate.
The metabolism of zinc in the
eye would appear to be concentrated mainly in the retina.
From the similarity of retinal and cerebral metabolism, it may
be inferred that the metabolism of zine in the eye is a relatively steady process.
Accordingly, the eyes of the fish from
the 1959 collection were selected as the index tissue for comparison of the levels of both stable and radioactive zinc.
6.21
Goatfish from Rongelap and Kabelle Islands.
The
data from Table 6 indicate the relative levels of stable zinc
and zinc-65 in various tissues of Kabelle fish.
The level of
zine in a tissue is dependent upon 3 basic factors:
zinc binding capacity,
(1) the
(2) the zinc exchange capacity and (3)
the availability of zinc to the tissue components.
The zinc
binding capacity is related to the number of binding sites
provided by the tissue components.
The zinc exchange capacity