Dynamics in immunocytochemical labelling of granules in the gonadotrops of the African catfish Clarias gariepinus, as a function of induced release

Abstract

The gonadotropic hormone (GTH) plays a regulative role in the reproductive cycle of teleosts. GTH-cell activity is under dual hypothalamic control i.e. stimulation by the peptide gonadotropin releasing hormone (GnRH) and inhibition by dopamine. Immunolabelling gives a specific localization of GTH in the granules of gonadotrops in the pituitary of the African catfish. Recently it has been shown for the pancreas, that the intensity of the labelling of secretory granules varies under different experimental conditions. In the present study a possible relationship between induced release of GTH and immunocytochemical labbeling of granules in catfish gonadotrops was investigated.