Figure 4.—Kidney of control fish (a) and of fish exposed to 24 ppm cadmium for 96hr(b). Note difference in the cell populations 
occupying the vascular spaces. 480; Azure-eosin stain. 
. a” Lee ; owes BEA SS 
- ‘ ee ee SS 
‘ ‘ ~- Fat + ees 
we eu © ey - ve : 
g. . : Jf x = a ; 
P é nS > 
ai ae * Race So ; > 
5 < . i tiled ~y 
Re : WP is 
oid * 
> a4 Yr 
[ =. < we \ “ty 
mek ‘\ * “Ky * x . ws Rite . 
wr. Soe 3 . ; - 
LJ 2 oe \ 
> ‘ * \ > ¥ & ss 
a * s i + , 
. bs - ‘ = é ‘ 
. ~ \ ‘ < 
. - ~ 
. ‘ . a * 2 ? . 
s ras . a | 
7 Prd t ¥ ’ ‘ 
. ° ~ * < 
5 -- * ¥ eq 
Ca Sry > we Wes 
w+ ‘ . 
Loman | 
. nN wt os . i 
’ \ * * ; 
\ - a abe 
< ole 
Figure 5.—Kidney of control fish (a) and of fish exposed to 48 ppm cadmium for 96 hr. An abundance of hemosiderin can be seen 
in the control fish. 120; Perl’s stain. 
the proximal tubules. Similar experimental results centrations in renal cortex reach approximately 200 
were obtained by Dalhamn and Friberg (1957); ppm wet-weight, functional and morphological 
Ahlmark et al. (1961) found decreased glomerular change occurs in the kidneys of rabbits, rats, and men 
filtration rates in human workers exposed to cad- (Friberg, Piscator, and Nordberg, 1971). After ad- 
mium. Proteinuria is another common finding in ditional exposure, the functional changes result in the © 
human cadmium workers (Friberg, 1950; Piscator, failure of the kidney to reabsorb the metallothionein, — 
1962). Proteinuria occurs subsequent to tubular and increased excretion of cadmium and a lowering of 
dysfunction because of decreased protein reabsorption the concentration of the metal in the kidney occurs. 
in the proximal tubule. The effect of cadmium poisoning on the amount of 
During chronic exposure or early in acute exposure, hemosiderin in the teleost kidney has not been 
cadmium is concentrated in the renal cortex in the previously described. Unlike most homeotherms, 
form of metallothionein, a cadmium- or zinc- many teleosts normally have a great deal of pigment 
containing protein with a molecular weight of about in the kidney, composed of both lipofuscin and 
10,000 (Kagi and Vallee, 1960). When cadmium con- hemosiderin. The observation of reduced pigment in 
30 
