Abstract
The present paper describes histological and cytological changes in the hypophysis and gonads of juvenile Tilapia (=Sarotherodon) mossambica exposed to the antigonadotropic drug methallibure (I.C.I.33, 828) by means of daily doses of 1 or 2 p.p.m.for 7 weeks.This treatment markedly prevented the process of maturation of gametogenesis in both sexes of fish, in addition to retardation of differentiation of interstitial cells and epithelial lining of the efferent duct of the testis.The polygonal basophils (gonadotrophs) located in the ventral portion of the proximal pars distalis of the hypophysis underwent a marked decrease in the cell size as well as in the amount of cytoplasmic granules of glycoprotein -aceous nature.Atrophy was manifested by the acidophils (somatotrophs) of the proximal pars distalis and the PAS positive cells of the pars intermedia, whereas no appreciable change was recognized in other cell types of the adenohypophysis.
