Date of Award:

5-1981

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Animal, Dairy, and Veterinary Sciences

Department name when degree awarded

Graduate Program in Toxicology

Committee Chair(s)

Joseph C. Street

Committee

Joseph C. Street

Committee

Ron Goede

Committee

Don Bone

Abstract

Toxaphene is reported to cause defects in the collagen of fish. Chronic exposure to toxhaphene weakens the backbone of fish by decreasing the amount of collagen and usually increasing the amount of calcium in the bone which results in a more brittle and fragile bone.

We investigated the possible direct action of toxaphene on collagen synthesis by exposing vertebral and swim bladder organ cultures obtained from unexposed rainbow trout (Salmo gairdneri) fingerlings to the same lot of toxaphene found to cause this defect in vivio. Collagen produced by these organ cultures was measured by: (1) total 3H-proline incorporated into the matrix; (2) 3H-proline released during collagenase digestion of acid-precipitated protein; (3) 3H-hydroxyproline extracted from the acid hydrolysate, and (4) tritiated water produced during the hydroxylation of 4-3H-proline. At a relatively high concentration of toxaphene (2.4 mM) these indices of collagen production were reduced, but this was probably caused by a decrease in tissue viability rather than by a direct affect on collagen synthesis. At 240 μM cellular protein synthesis was reduced. Generally no effects were found at toxaphene concentrations below 240 μM. From these studies it was concluded that toxaphene does not have a direct inhibitory effect upon collagen production at the tissue level.

For comparison to the in vitro experiments, the weight, length, and vertebral prolyl hydroxylase activity of fish exposed for 60 days to toxaphene in vivo were measured. All three of these parameters were significantly reduced in comparison to controls (α = 0.05) in those fish exposed to the highest concentration of toxaphene (200 ng/1). fish exposed to 150 ng/l toxaphene also had reduced prolyl hydroxylase activity. These results indicated that vertebral prolyl hydroxylase activity may be a sensitive indicator of toxaphene exposure in fish, and inhibition of that enzyme may be involved in the mechanism of toxaphene-induced collagen effects.

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