The binding of estrogen to endometrium and uterine arteries of the ewe was investigated by use of a [³H]estradiol exchange assay and by incubating whole tissue aliquants with [³ H]estradiol, a method which permits quantification of bound estrogen translocated from the cytoplasm to the nucleus. Five ewes were necropsied on...
Two experiments were conducted to determine whether in
ewes uterine concentrations of estrogen and progesterone
receptors are affected by the presence of a conceptus or by
the hormonal milieu associated with extremes in photoperiod
to which ewes are exposed.
In Exp.1, nine mature ewes were unilaterally
ovariectomized by removing an...
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 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...
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...
The mechanism(s) involved with intrauterine migration of the porcine embryo was investigated. Twenty-four gilts on Days 6, 9 and 12 of gestation (Day 0 = 1st day of estrus) were utilized to examine the relationship between myometrial activity and intrauterine migration. On Day 2, embryos were flushed from one oviduct...