Histochemical and electron microscopic studies on the pituitary gonadotropic cells of the fish, notopterus notopterus

Gonadotropic cells are distributed in the proximal pars distalis of the pituitary in Notopterus notopterus. Histochemical and electronmicroscopic techniques are applied for the present study. The PPD of pituitary gland in zero age group fish has very little number of gonadotropes. The cells are undifferentiated with indistinct boundaries. They markedly increased in number in one year aged fish, since the gonads of this age group fish shows advanced stages of growth. The gonodotropes that largely occupy the medial aspect of the PPD increased numerically as the gonads mature and become major cell type before spawning in two age group fish. The electronmicroscopic studies reveals that, they appear oval or elongated containing a few large granules and many small lucent secretory granules and based on this two GTH cell type could be identified in the PPD containing different types of secretory granules. The differentiation and presence of two types of gonadotropes needs further verification in the fish N. notopterus.