Receptor-mediated mechanism for the transport of prolactin from blood to cerebrospinal fluid

Journal Article · Fri May 01 00:00:00 EDT 1987 · Endocrinology; (United States)

DOI:https://doi.org/10.1210/endo-120-5-1846· OSTI ID:6478552

Walsh, R J; Slaby, F J; Posner, B I

Prolactin (PRL) interacts with areas of the central nervous system which reside behind the blood-brain barrier. While vascular PRL does not cross this barrier, it is readily accessible to the cerebrospinal fluid (CSF) from which it may gain access to the PRL-responsive areas of the brain. Studies were undertaken to characterize the mechanism responsible for the translocation of PRL from blood to CSF. Rats were given external jugular vein injections of (/sup 125/-I)iodo-PRL in the presence or absence of an excess of unlabeled ovine PRL (oPRL), human GH, bovine GH, or porcine insulin. CSF and choroid plexus were removed 60 min later. CSF samples were electrophoresed on sodium dodecyl sulfate-polyacrylamide slab gels and resultant autoradiographs were analyzed with quantitative microdensitometry. The data revealed that unlabeled lactogenic hormones, viz. oPRL and human GH, caused a statistically significant inhibition of (/sup 125/I)iodo-PRL transport from blood to CSF. In contrast, nonlactogenic hormones, viz bovine GH and insulin, had no effect on (/sup 125/I)iodo-PRL transport into the CSF. An identical pattern of competition was observed in the binding of hormone to the choroid plexus. Furthermore, vascular injections of (/sup 125/I)iodo-PRL administered with a range of concentrations of unlabeled oPRL revealed a dose-response inhibition in the transport of (/sup 125/I)iodo-PRL from blood to CSF. The study demonstrates that PRL enters the CSF by a specific, PRL receptor-mediated transport mechanism. The data is consistent with the hypothesis that the transport mechanism resides at the choroid plexus. The existence of this transport mechanism reflects the importance of the cerebroventricular system in PRL-brain interactions.

• Research Organization: George Washington Univ. Medical Center, Washington, DC
• OSTI ID: 6478552
• Journal Information: Endocrinology; (United States), Vol. 5
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CEREBROSPINAL FLUID
AUTORADIOGRAPHY
LTH
BIOCHEMICAL REACTION KINETICS
TRANSLOCATION
BLOOD
BLOOD-BRAIN BARRIER
IODINE 125
LABELLED COMPOUNDS
RATS
USES
ANIMALS
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BODY FLUIDS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
GONADOTROPINS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
KINETICS
MAMMALS
MATERIALS
NUCLEI
ODD-EVEN NUCLEI
PEPTIDE HORMONES
PITUITARY HORMONES
RADIOISOTOPES
REACTION KINETICS
RODENTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques