Estrogen and progesterone receptor content in the pituitary gland and uterus of progesterone-primed and gonadotropin releasing hormone-treated anestrous ewes.
The objective of this work was to investigate the effect of progesterone (P) and gonadotropin-releasing hormone (GnRH) treatment on estrogen receptor (ER) and P receptor (PR) concentrations in the pituitary gland and uterus of anestrous ewes. Ewes were either not treated (group C, n = 4); were treated with 0.33 g P-controlled internal drug release (P-CIDR) for 10 days (group P, n = 4), with GnRH, 6.7 ng i.v. injections every 2 h for 18 h followed by a 4 microg bolus administration of Receptal at 20 h (group GnRH, n = 4), or with a combination of the P and GnRH treatment (group P + GnRH, n = 3). Ewes were humanely killed either at the beginning of the experiment (group C), when the CIDR was removed (group P), or 24 h after the GnRH bolus treatment (groups GnRH and P + GnRH). Progesterone treatment increased serum P concentrations, indicating that the treatment was effective. All GnRH treated ewes had similar luteinizing hormone (LH) surges, which lasted 8 h. At slaughter, estradiol (E2) concentrations in the GnRH group were higher than in groups C, P, and P + GnRH. Treatment with GnRH increased more than 10-fold the content of ER and PR in the pituitary gland without altering steroid receptor concentrations in the uterus. When GnRH was combined with P the uterine receptor contents were higher than with P treatment alone. The treatment with P decreased ER and PR content in the uterus, but had no effect on the pituitary gland. The results show that regulation by P and GnRH of ER and PR content in anestrous ewes is tissue-specific.
Tasende
C
C
Department of Molecular and Cellular Biology, Veterinary Faculty, Lasplaces, Montevideo, Uruguay. ctasende@adinet.com.uy
Meikle
A
A
Rodríguez-Piñón
M
M
Forsberg
M
M
Garófalo
E G
EG
D000780:Anestrus; D000818:Animals; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D009929:Organ Size; D006080:Ovarian Follicle / Q000033:anatomy & histology; D010053:Ovary / Q000033:anatomy & histology; D010902:Pituitary Gland / Q000033:anatomy & histology / Q000737:chemistry / Q000187:drug effects; D011374:Progesterone / Q000494:pharmacology*; D011960:Receptors, Estrogen / Q000032:analysis*; D011980:Receptors, Progesterone / Q000032:analysis*; D012756:Sheep / Q000378:metabolism*; D014599:Uterus / Q000033:anatomy & histology / Q000737:chemistry / Q000187:drug effects
D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone