A prolactin release inhibiting activity isolated from neurointermediate lobe extracts is an endothelin-like peptide.
A prolactin release-inhibiting factor has been reported in extracts of rat and bovine neurointermediate lobes of the pituitary gland. This material when isolated by Sephadex G-25 chromatography or by C-8 high pressure liquid chromatography coelutes with synthetic forms of all members of the mammalian endothelin family of peptides and with their immediate precursors, big-ET-1 and big-ET-3. The endogenous material crossreacts in an endothelin radioimmunoassay. Immunohistochemical analysis of endothelin-like immunoreactivity in the neurointermediate lobe revealed a predominantly intermediate lobe localization. Individual immunopositive cells were visualized in the intermediate lobe. Preabsorption of chromatographically isolated prolactin release-inhibiting activity with an endothelin antiserum which recognizes all members of the ET family of peptides abolishes its in vitro bioactivity. These results suggest that a prolactin release-inhibiting activity present in the neurointermediate lobe is endothelin or an endothelin-like peptide.
Samson
W K
WK
Department of Anatomy and Neurobiology, University of Missouri School of Medicine, Columbia, MO 65212.
Skala
K D
KD
Alexander
B D
BD
Huang
F L
FL
Gomez-Sanchez
C
C
D000818:Animals; D001681:Biological Assay; D016232:Endothelins / Q000032:analysis*; D005260:Female; D066298:In Vitro Techniques; D010902:Pituitary Gland / Q000737:chemistry*; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D016232:Endothelins; D011388:Prolactin