Domitran, G.: Comparative characteristics of the pituitary of the horse, dog, bottlenose dolphin and striped dolphin. Diploma Thesis. Faculty of Veterinary Medicine. Zagreb, 2007

Abstract

Detailed microscopic anatomy of the most organs, also as pituitary of the marine mammals is less known. Those investigations intend to describe general microscopic structure of the pituitary of the bottlenose dolphin and striped dolphin with different histological techniques, and compare its results between two dolphin species and with the same data of the well-known pituitaries of horse and dog as typical land mammals. Pituitary of the both investigated dolphins is elongate, with shape of the flattened baton, which is transversally place on the bottom of the cranial cavity. Infundibulum and pars nervosa are located in the middle part of pituitary, and because of that dolphin’s pituitary is different from the pituitary of dog, horse, and human and other land mammals. Pars nervosa of the dolphin pituitary is pursue from the infundibulum, and it is divided on two arms which is ramificated, and which ingrowths in the lateral part or pars distalis of the pituitary. Because of that relation between neurohypophyse and adenohypophyse, it is difficult to talking about neurohypophyse as anterior, and adenohypophyse as posterior lobe of the dolphin’s pituitary. The cells of the pars distalis pituitary of the both investigated dolphins are well differentiating. The number of the chromophobe adenohypophysal cells decrease from peripheral to the central part of the pituitary and neurohypophyse, and number of the basophile chromophile cells are increase. That relation and arrangement of the adenohypophysal cells was not observed in the pituitary of horse and dog. All cells of the pars distalis of the both investigated dolphins are positive on the PAS reaction, and that coloring is much intensive than in the same cells of the horse and dog. General difference between pituitary of investigated dolphins and horse and dog is absence of the pars intermedia and hypophyseal cavity in dolphin pituitary. In the pars distalis of the pituitary of the both investigated dolphins observed was circular or oval shaped groups of cells which are sharp demarcate from the other or typical adenohypophyseal cells. Cells of those groups from dolphin’s pituitary have similar reactions on histological coloring as the cells of the pars intermedia of the horse and dog pituitary. That data open new hypothesis about possibility that those unspecific cells in dolphin pituitary are cells of pars intermedia of the dolphin’s pituitary.