Cellular events in adenohypophysis of Trichogaster trichopterus (Pallas) during final oocyte maturation

Abstract

A histological study using light and electronic microscopy was conducted on the pituitary cellular structure of gourami (Trichogaster trichopterus) to observe changes occurring during the reproductive cycle of the female. The main changes
were detected when the ovary passed from vitellogenesis to final oocyte maturation (FOM) in gonadotropin (GtH) cells, whereas no changes were found in other cells. A general decrease in the staining of the entire region of GtH
cells was noted at the start of the maturation process. An increase in the number of chromophobic cells was detected mainly along the periphery. Some GtH cells of fish found at FOM showed nuclei that were more hypertrophic than
those of vitellogenic females. At the ultra-structural level, a decrease in the number of secretory granules in some GtH cells of females examined during FOM was detected, however large globules characterizing this cell type were still found. In fish examined after larvae were found in the nest (at least 48
hours after spawning), the gonadotropic cells showed a staining pattern similar to that found in non-reproductive fish.