[Histochemical study of tanycytes in connection with the adrenocorticotropic function of the hypophysis].

Chronic experiments were conducted on sexually mature rats; histochemical study of the activity of some redox enzymes (glutamic dehydrogenase, lactic dehydrogenase, glucoso-6-phosphoric dehydrogenase, glycerophosphoric dehydrogenase, and succinic dehydrogenase) was carried out in the ependymal cells of the floor of the third cerebral ventricle, the so called tanycytes, in case of an increased adrenocorticotrophic function of the hypophysis attained by bilaterial adrenalectomy, and in depression of this function as a result of chronic dexametasone administration. The activity of the enzymes under study decreased 2, 3 and 4 weeks after bilateral adrenalectomy. The activity of lactic dehydrogenase, glucerophosphoric dehydrogenase and succinic dehydrogenase increased in the tanycytes during administration of 5 gamma of dexametasone. Chronic administration of 100 gamma of dexametasone was accompanied by a toxic action of the preparation (a marked reduction in the weight of the adrenal glands, a negative body weight gain, and an aggravation of the animal's general condition). The results obtained pointed to the existence of a reverse correlation between the metabolic activity of tanicytes and the adrenocorticotrophic function of the hypophysis.