ELEVATED CONCENTRATIONS OF MITOCHONDRIAL PERIPHERAL BENZODIAZEPINE RECEPTORS IN OVARIAN-TUMORS

Using PK 11195, a high affinity ligand for peripheral benzodiazepine r eceptor (PBZr) binding sites in isolated mitochondria (m-fraction) and microsomal fraction (p-fraction) from human ovaries and ovarian tumor s were studied. Binding in both m and p-fractions from ovaries and tum ors were saturable and of high affinity. The PBZr density in m-and p-f ractions from ovaries was very similar whereas the binding in m-fracti on in ovarian tumors was nearly 3-fold higher than p-fraction. There w as no significant difference in the binding affinities (K-D values) fo r PK 11195 in the various fractions. The selective increase in the den sity of PBZr in mitochondria of tumors suggests an association with en ergy demand and utilization. The role of a relatively high density of PBZr in microsomal fractions remains to be elucidated.