ESTRADIOL CONJUGATED TO BSA RELEASES OXYTOCIN FROM SYNAPTOSOME-CONTAINING HOMOGENATES FROM THE MEDIAL PREOPTIC AREA-HYPOTHALAMUS

Estradiol conjugated to bovine serum albumin at position 6 (E-6-BSA) r eleased oxytocin (OT) from homogenates of the medial preoptic area and medial hypothalamus (MPOA-MH) within minutes of its superfusion. Usin g a superfusion system in which synaptosome-containing homogenates wer e layered onto acrodiscs maintained at 37 degrees C, we have found tha t E-6-BSA (100 ng/mu l) superfusions significantly elevated OT release within minutes. In contrast, superfusion of the same concentration of BSA or progesterone-3-BSA (P-3-BSA) had no effect on OT release. Whil e superfusing homogenates with augmented levels of K+ had no effect on OT release itself, superfusing E-6-BSA with these concentrations of K + consistently increased OT release. This is the first demonstration t hat E-6-BSA increases OT release in a nucleus-free medium.