Radioautographic study of binding and internalization of corticotropin-releasing factor by rat anterior pituitary corticotrophs

Journal Article · Sun Jan 01 04:00:00 EST 1984 · Endocrinology; (United States)

DOI:https://doi.org/10.1210/endo-114-1-14· OSTI ID:6743218

Leroux, P; Pelletier, G

In order to identify the anterior pituitary cell type(s) containing corticotropin-releasing factor (CRF) receptors and to study the internalization processes of this peptide by the target cells, radioautography was performed on rat anterior pituitaries removed at specific intervals (2-60 min) after intracarotid injection of (/sup 125/I)iodo-CRF into intact and adrenalectomized female rats. In intact animals, all corticotrophs were labeled, whereas in the adrenalectomized animals about 80% of the hypertrophied corticotrophs (adrenalectomy cells) were. In control animals injected with both iodinated CRF and an excess of unlabeled peptide, no specific reaction could be detected. The time-course study in intact animals showed that 2 min after injection most silver grains were found over or within 160 nm of the plasma membrane. At the 5-min time intervals, grains were observed both over the plasma membrane and within the cytoplasm, associated with lysosomes, and the Golgi apparatus. Fifteen minutes after injection, grains were mostly found over lysosomes and the Golgi apparatus, whereas at the longest time intervals (30 and 60 min) almost no labeling could be detected. The results obtained in this study indicate that in the anterior pituitary CRF receptors are restricted to corticotrophs (as identified by electron microscopy) and that, after binding to the plasma membrane, CRF is rapidly internalized to Golgi elements and lysosomes.

• Research Organization: Centre Hospitalier Universite Laval, Quebec
• OSTI ID: 6743218
• Journal Information: Endocrinology; (United States), Journal Name: Endocrinology; (United States) Vol. 114:1; ISSN ENDOA
• Country of Publication: United States
• Language: English

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551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADRENAL HORMONES
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BODY
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ENDOCRINE GLANDS
GLANDS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
ORGANS
PEPTIDE HORMONES
PHYSIOLOGY
PITUITARY GLAND
PITUITARY HORMONES
RADIOISOTOPES
RATS
RECEPTORS
RODENTS
STEROID HORMONES
TRACER TECHNIQUES
VERTEBRATES