Binding of an iodinated substance P analogue to cultured anterior pituitary prolactin- and luteinizing hormone-containing cells.
Several lines of anatomic, biochemical, and pharmacological evidence suggest that the neuropeptide substance P has a direct action on cells of the anterior pituitary lobe via a specific neurokinin-1 receptor. In the present study we confirmed this association by combining Bolton-Hunter iodinated substance P-receptor autoradiography with immunocytochemistry on cultured anterior pituitary cells. Radiolabeled substance P was bound to living cell cultures at 0 degrees C, and after a brief wash the cultures were fixed and processed immunocytochemically for prolactin and luteinizing hormone. A large proportion of cultured anterior pituitary cells possessed substance P binding sites. When receptor autoradiography was combined with immunocytochemistry, it was evident that both prolactin- and luteinizing hormone-immunoreactive cells were labeled with radiolabeled substance P. However, a small proportion of the radioligand-labeled cells were not stained by the immunocytochemical procedure, suggesting that additional cell types possess substance P receptors. The present study presents morphological evidence that substance P binds to prolactin- and luteinizing hormone-containing cells of the anterior pituitary lobe. Therefore, it is likely that substance P has a direct action on mammotrophs and gonadotrophs.
Institute of Medical Anatomy B, University of Copenhagen, Denmark.
P J
PJ
Larsen
T
T
Saermark
S E
SE
Mau
D000818:Animals; D001345:Autoradiography; D001665:Binding Sites; D002478:Cells, Cultured / Q000378:metabolism; D007457:Iodine Radioisotopes; D007986:Luteinizing Hormone / Q000032:analysis*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000378:metabolism*; D011388:Prolactin / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter / Q000032:analysis*; D013373:Substance P / Q000031:analogs & derivatives* / Q000378:metabolism
D007457:Iodine Radioisotopes; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter; D013373:Substance P; D011388:Prolactin; D007986:Luteinizing Hormone