Morpho-Histological architecture of various cells with special emphasis on the seasonal variations of gonadotrophs in the pituitary gland of Notopterus notopterus (Pallas, 1769) in relation to testicular maturation

The pituitary gland of Notopterus notopterus (Pallas, 1769) was situated in a shallow pit at the floor of the skull and attached to the infundibulum. On the basis of tinctorial properties the cell types of pituitary were indentified which were distributed in the rostral pars distalis (RPD) proximal pars distalis (PPD) and pars intermedia (PI) in different proportions. The three zones were innervated by the narrow process of neurohypophysis. The acidophilic prolactin cells (PRL) and adrenocorticotropic cells (ACTH) were observed in the RPD which were stained with acid fuchsin and orange G by respectively. The basophilic gonadotrophs (GTH) and thyrotrophs (TSH) were distributed in the middle PPD and reacted positively to aniline blue, periodic acid Schiff’s (PAS) and aldehyde fuchsin (AF) stain. The only acidophilic somatotrophs (STH) cells were also distributed in between GTH in PPD region which were positively stained with PAS and acid fuchsin. The GTH and TSH cells exhibited both quantitative and qualitative variations during the testicular cycle. The seasonal changes in the testes of N. notopterus have been described according to the variations in GSI values and frequency percentages of the different germ cells occurring in the testicular lobules. The sequential changes of GTH and TSH cells and testicular activities were correlated well during different reproductive phases.