Search Results
You are looking at 1 - 2 of 2 items for
- Author: S. UHLARIK x
- Refine by access: All content x
Search for other papers by F. E. SZONTÁGH in
Google Scholar
PubMed
Search for other papers by S. UHLARIK in
Google Scholar
PubMed
The gonadotrophin content of the pituitary of intact mature female rats decreases considerably after treatment with pregnant mare serum (PMS) (Szontágh, Uhlarik & Jakobovits, 1963). This phenomenon might be explained by assuming that gonadotrophins act on the hypothalamus, not only by mediation of the gonads, but also directly. The possibility that a direct 'internal' feedback of this kind exists was recently discussed by Szentágothay, Flerkó, Mess & Halász (1962), and has actually been proved with respect to the regulation of ACTH secretion. Sawyer & Kawakami (1961) have suggested that a direct feedback mechanism exists between the hypothalamus and the adenohypophysis, also involving the gonadotrophic hormones. Török (1962) reported the existence of a two-directional blood-flow in the portal vascular system of the adenohypophysis, to and from the hypothalamus, thus demonstrating the anatomical route by which chemical mediators might pass between the pituitary and the hypothalamus. In previous investigation on intact animals
Search for other papers by B. HALÁSZ in
Google Scholar
PubMed
Search for other papers by L. PUPP in
Google Scholar
PubMed
Search for other papers by S. UHLARIK in
Google Scholar
PubMed
SUMMARY
Anterior pituitary tissue was implanted into the hypothalamus, other parts of the brain and beneath the renal capsule of rats. Grafts in the ventral hypothalamus could retain a normal histological appearance despite a lack of any contact with the capillary loop system of the median eminence.
By observing the location of basophils in the grafts a 'hypophysiotrophic' area has been defined. In other sites the histological structure of the grafts was not maintained.
In animals with grafts in the hypophysiotrophic area the target organs might be well preserved, though sometimes the gonads were preserved and other target organs atrophied. Grafts in other sites always led to atrophy of the target organs.
It is concluded that the material from the hypothalamus essential for the maintenance of anterior pituitary structure and function is not simply a synaptic mediator discharged by nerve terminals into the portal circulation, but a true neurosecretory substance produced by and available from small neurones in the hypothalamus.
