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...
To determine whether membrane-related events may be involved in
attenuated luteal function after gonadotropin-releasing hormone (GnRH)
administration, corpora lutea (CL) were removed from 10 beef heifers on day 7
of the estrous cycle after i.v. injection of GnRH or saline on day 2 of the cycle.
Luteal slices were incubated...
Prolactin (PRL) is a peptide hormone that is involved in a number of diverse physiologic roles, particularly with respect to reproduction, including: influencing sexual and parental behaviors, onset of puberty, regulation of seasonal reproduction, follicular maturation, ovulation, luteinization and corpus luteum (CL) function, steroidogenesis, mammary gland development and lactation, testicular...
Two experiments were conducted to evaluate the effects of
gonadotropin releasing hormone (GnRH) on the function of the bovine
corpus luteum during the estrous cycle. In Experiment 1, 10 heifers
were assigned randomly into two groups with each heifer serving as
her own control. Heifers in Group I (n=5) were...
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)...
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...