Date of Award


Document Type

Dissertation - Restricted

Degree Name

Doctor of Philosophy (PhD)


Biological Sciences

First Advisor

Victor de Vlaming

Second Advisor

Ellen Rasch

Third Advisor

Ralph Meyer

Fourth Advisor

Terry Hall

Fifth Advisor

Bela Piacsek


The physiology of temperate zone teleost fishes is regulated in part by various fluctuating environmental parameters. Little is known, however, about how these environmental variations are translated into the regulation of physiological processes.

The pineal organ in some fishes may be a photoreceptor or mediator of photoperiod information. This suggests that the pineal may be involved in physiological adjustments to photoperiod shifts. Since many physiological events in fishes are modulated by photoperiod, it was of interest to determine whether removal of this organ affected some of the various parameters known to be influenced by environmental lighting. Both reproductive activity and prolactin physiology in some fishes are known to be controlled, in part, by photoperiod. Thus, the effects of pinealectomy on pituitary prolactin levels, and on pituitary and plasma gonadotropin titres and gonadal development in fish exposed to various photoperiod-temperature regimes were examined.



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