The microscopical structure and quantitative changes of pituitary cell populations in frogs (Rana esculenta L.)...

The percentage of cell populations of hypophysis pars distalis, their ultrastructure, degranulation phenomena and volume of cell nuclei easured by karyometry was examined in frogs, Rana esculenta L. irradiated by UV light. The observed changes, reflecting alterations of the secretory activity were most prominent in B2 cells producing gonadotropic hormones and in B3 cells probably responsible for the secretion of ACTH. A concomitant increase of the number of chromophobic cells was observed. The obtained results are discussed in relation to data from the existing literature.