Met-enkephalin receptors in human gliomas.
Endogenous opioid systems (opioid peptides and receptors) are involved in many functions including the regulation of cell growth. We investigated the presence of Met-enkephalin binding sites in gliomas by displacement assays. Results demonstrated that few gliomas exhibit Met-enkephalin binding sites and that the percentage of tumours which express these binding sites strongly decreases with increasing malignancy. Moreover, we observed a shift from mu Met-enkephalin binding sites in low grade gliomas to delta Met-enkephalin binding sites in high grade gliomas. These results suggest an inactivation of the Met-enkephalinergic system in gliomas which could lead to loss of the inhibitory effect exerted by Met-enkephalin on normal astrocyte growth and thus favour progression of malignancy.
Molin
L
L
Unité INSERM 318, Hôpital Michallon, Grenoble, France.
Verna
J M
JM
Nissou
M F
MF
Benabid
A L
AL
D001665:Binding Sites; D005910:Glioma / Q000378:metabolism*; D006801:Humans; D011957:Receptors, Opioid / Q000145:classification / Q000378:metabolism*; D017465:Receptors, Opioid, delta / Q000378:metabolism; D017450:Receptors, Opioid, mu / Q000378:metabolism; D014407:Tumor Cells, Cultured
D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; C033593:methionine-enkephalin receptor