ISSN:
1432-0878
Keywords:
GnRH receptors
;
Gonadotropes
;
Coated pits
;
Internalization
;
High-resolution autoradiography
;
LHRH, Gonadoliberin
;
Pituitary gland
;
Rat
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Localization of GnRH receptors in rat pituitary gonadotropes was studied by use of 125I-[azidobenzoyl-D-Lys6]GnRH which, upon photolysis, is covalently bound to the receptor molecule. Using high resolution autoradiography, it was found that, after a 90-min incubation of the analog with pituitary cells at 4° C, 93% of the silver grains were associated with the plasma membrane of the gonadotropes. After 45-min incubation of the cells at 37° C, clustering and internalization of the receptor-bound GnRH analog were evident. Silver grains were associated with coated pits, intracellular vesicles, Golgi complexes, lysosome-like structures and secretory granules. The data indicate that receptor-bound GnRH agonist is internalized, at least in part, via coated pits and is subsequently routed to lysosomes where degradation of the hormone-receptor complex may occur. The presence of a considerable amount of silver grains associated with secretory granules may suggest that some of the internalized receptor molecules can escape degradation and be recycled to the cell membrane.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00214895
