Anterior pituitary homografts were studied with the aid of the peroxidase labeled antibody method, for LH, FSH, ACTH and prolactin. Hormone-containing cells were present in all properly vascularized pituitary transplants irrespective of their location, while cytologic characteristics of the grafts were closely correlated with their location. Hypertrophied gonadotrophic cells were found exclusively in grafts located in the hypophysiotrophic area (HTA) of the hypothalamus. The low hormone content in the hypertrophic gonadotrophs suggested a release of the hormone synthesized by these cells, while the small gonadotrophs in grafts situated outside the HTA or under the renal capsule appeared to be in an inactive storing stage. Similar, albeit less pronounced, cytologic differences were observed in ACTH cells. No correlation could be found between the hormone content of prolactin cells and the location of the graft. In serial sections of hypothalami bearing pituitary grafts and stained alternately for gonadotrophic cells and LH-RH fibers, no relation was found between the presence of LH-RH-containing fibers and active, hypertrophied gonadotrophic cells of the graft. This appeared to indicate that the presence of HTA and its direct contact with the LH-RH-containing neuronal elements could not be the decisive factor in the maintenance of the secretory activity in the graft. As an alternative interpretation to the origical concept of Halasz et al.. the possible role of a vascular link between the median eminence capillaries and the 'hypophysiotrophic area' is suggested. The possible relation between the HTA and an ultra-short feedback control of hypothalamic neurohumoral functions is discussed.
|Number of pages||13|
|Journal||Acta morphologica Academiae Scientiarum Hungaricae|
|Publication status||Published - Jan 1 1976|
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