Experiments were conducted to characterize the nongenomic effects of
progesterone (P4) on binding of oxytocin (OT) to the ovine oxytocin
receptor (OTR) and signal transduction. The dose-response relationship of
P4 to OT binding to the OTR in endometrium was examined. Progesterone
interfered with the binding of OT to the OTR...
Four experiments were conducted to determine oxytocin concen tration of bovine luteal tissue at different stages of the estrous cycle and to study the effects of prostaglandins F₂α (PGF₂α), E₂ (PGE₂), luteinizing hormone (LH), cycloheximide, colchicine and cytochalasin B on oxytocin synthesis and release in vitro. In experiment 1, luteal...
Experiments were conducted to examine the effects of a tumor-promoting phorbol ester, a calcium ionophore and indomethacin on bovine luteal oxytocin (OT) synthesis and secretion and progesterone secretion. Six 18-month-old crossbred beef heifers in Exp. 1 and five similar heifers in Exp. 2 were observed twice daily for estrus using...
Effects of progesterone (P₄) and mifepristone (RU 486) on binding
of oxytocin (OT) to its ovine uterine receptor (OTR) were studied in two
experiments. Two additional experiments were conducted to evaluate
specific binding sites for P4 in endometrial plasma membranes. In Exp.
1, ovariectomized ewes were injected with estradiol-17β (E₂)...
Experiments were conducted to determine whether endogenous progesterone regulates synthesis and/or secretion of luteal oxytocin (OT). In experiment 1, mature ewes (n=5 per group) were assigned randomly to control or mifepristone (RU 486) treatment groups. Ewes were injected twice daily s.c. with vehicle or 10 mg RU 486 from days...
The present study explored the effects of intranasal oxytocin (OT), a naturally occurring hormone, on the behavior of pet dogs in an attachment test. Each dog participated in two testing sessions. On one visit saline was administered nasally and on another OT was administered nasally. Condition order was counterbalanced. Following...
Prostaglandin F₂α (PGF₂α), a stimulatory hormone of luteal oxytocin
secretion, is known to activate protein kinase C (PKC); however, the
intracellular signals that promote exocytosis of oxytocin remain to be
elucidated. Myristoylated alanine-rich C kinase substrate (MARCKS), a
protein specifically phosphorylated by PKC, crosslinks actin filaments
associated with the inner...