Cyclic changes in the pituitary gonadotrophs in relation to the ovarian cycle inPuntius sarana(Hamilton) (Teleostea)

Abstract

Abstract The three glandular regions of the Puntius sarana pituitary gland namely, the rostral pars distalis (RPD), the proximal pars distalis (PPD) and the pars intermedia (PI) are arranged one below the other in a dorso‐ventral axis. The gonadotrophs (GTH cells) are largely confined to the PPD region and they are easily identified by their positivity with aldehyde fuchsin, aldehyde thionin, aniline blue, Alcian blue and PA‐Schiff staining. Immunohistochemistry, using the antiovine LH‐s‐subunit, antisalmon GTH and antisilver carp GTH as antisera, confirms that the GTH cells are of LH type. In the fully mature female, GTH cells apparently fall into two categories, a larger LH type and a smaller second one whose significance is not clear. The study of two successive annual reproductive cycles indicates the existence of a good correlation between cyclic changes in the secretory activity of GTH cells and the ovarian cycle. The GTH cells attain maximum size and percentage values in May and June coinciding wit...