Androgens in teleost fishes

Effects of stress on fish reproduction, gamete quality, and progeny

Seasonal variations in the immune system of lower vertebrates

Much evidence suggests that intrinsic molecular or cellular aging mechanisms need not be invoked to explain most age-related cellular changes and pathologcical conditions. Analysis of a widely scattered literature indicates that hormones and neural factors regulate a great number of cellular aging phenomena of mammals. It is proposed that age-related changes after maturation result from an extension of the neural and endocrine mechanisms that control earlier development and that produce a regulatory cascade of changing neural, endocrine, and target-tissue interactions.

The Regulation of Physiological Changes During Mammalian Aging

A basic premise in any intensive culture system is to maximize growth at minimum cost, with an end product that is of high nutritive value and aesthetically acceptable to the consumer. This review is directed towards evaluating the role for thyroid hormones and steroids in fish culture. Particular attention has been given to the following topics: growth, appetite, food conversion, carcass composition, salt water tolerance, species specificity, deleterious responses and economic implications.

Application of thyroid and steroid hormones as anabolic agents in fish culture

A histological study was made of the various organs and tissues of the Pacific salmon at successive stages of sexual maturation from the sea to the spawning grounds. Pronounced changes were found in the body structures of the spawning salmon prior to death. These consisted principally of degeneration with or without atrophy as shown by the stomach, liver, spleen, thymus, thy-roid, gonads, pituitary, kidney and cardiovascular system. On the contrary, certain organs exhibited hypertrophy and hyperplasia, e.g., adrenal, pancreatic islets and skin. The inception of some of the above changes was detected several months before full sexual maturity. Comparison with the histological altera-tions occurring in Cushing’s syndrome, experimental hyperadrenocorticism and aging, suggested that many of the tissue changes found in the salmon could be ascribed to the effects of hyperactivity of the adrenal gland. Previous finding of high concentrations of 17-OHCS in the plasma of spawning salmon lends sup-port to this infe...

Histological changes in the organs and tissues of migrating and spawning Pacific salmon (genus Oncorhynchus).

A comparative study was made of the histological changes occurring in the adrenal cortical tissue of the Pacific salmon, the sea-run steelhead trout, and the non-migratory rainbow trout at various stages in their life cycles with the purpose of ascertaining whether there exists a relationship between degree of adrenal hyperplasia at spawning and survival thereafter. These three fishes show varying post-spawning outcomes from death of all the salmon to partial mortality in steelhead to usual survival of the rainbow trout. The adrenal cortical tissue, found in the cephalic end of the kidney, consists in the sexually immature fish of small isolated groups of characteristic cells which are usually associated with branches of the cardinal vein. With the onset of gonadal development the adrenal cells begin to increase in number and by the time sexual maturity is reached in the salmon and steelhead, marked hyperplasia is present. The cells of this hyperplastic tissue are larger than those in the immature fish an...

Hyperplasia of the adrenal cortical tissue in pacific salmon (genus oncorhynchus) and rainbow trout (salmo gairdnerii) accompanying sexual maturation and spawning

O. H. Robertson

Papers

Histological changes in the organs and tissues of migrating and spawning Pacific salmon (genus Oncorhynchus).

Hyperplasia of the adrenal cortical tissue in pacific salmon (genus oncorhynchus) and rainbow trout (salmo gairdnerii) accompanying sexual maturation and spawning

Pituitary Degeneration and Adrenal Tissue Hyperplasia in Spawning Pacific Salmon

Histological changes in the pituitary gland of the rainbow trout (Salmo gairdnerii) accompanying sexual maturation and spawning.

Histological changes in the pituitary gland of the Pacific salmon (genus Oncorhynchus) accompanying sexual maturation and spawning.