PITUITARY - LOBULATION AND SEASONAL CHANGES OF THE BASOPHIL PITUITARY IN CYPRINIDS

The pituitary gland is noted through distinct Irticularities to those of the other vertebrates. Within this class there are morphological variations in form, the size and lobulation of the pituitary gland. Thus, in some species, adenohypophysis is not anatomically divided but it is consisting of a single lobe. In many species of Teleostei adenohypophysis it consists of two lobes, one anterior or distally subdivided into two zones and the other intermediate. The present paper aims to highlight the structure of the pituitary gland and cell types present in cyprinids lobes. The studies were performed on microscopic preparations containing sagittal sections through carp pituitary. The sagittal histological sections made of 5 mu m reveal the presence of two distinct parts: neurohypophyses ofnervous origin, and the adenohypophysis of epithelial origin. Considering the scientific importance and the practice ofpituitary hormones in stimulating the maturation of gonads in fish also followed the changes of the pituitary structure, especially of the middle gonadotropic lobe. The histological study ofthe pituitary gland in the H. molitrix species at different times ofthe year has given us the possibility to track the seasonal variations of the basophil gonadotropic lobe structure. In the present study demonstrated that during the annual cycle, GTH cells go through different stages of activity that are not synchronous in all cells GTH. We were able to draw conclusions regarding the best period for harvesting pituitary glands usedfor pituitary injections under artificial reproduction conditions.