PMID- 17429013
OWN - NLM
STAT- MEDLINE
DCOM- 20070925
LR  - 20181201
IS  - 0006-3363 (Print)
IS  - 0006-3363 (Linking)
VI  - 77
IP  - 2
DP  - 2007 Aug
TI  - Differential modulation of gonadotropin secretion by selective estrogen receptor 
      1 and estrogen receptor 2 agonists in ovariectomized ewes.
PG  - 320-8
AB  - The objectives of this study were to determine whether activation of estrogen 
      receptor 1 (ESR1; also known as ERalpha), or estrogen receptor 2 (ESR2; also 
      known as ERbeta), or both are required to: 1) acutely inhibit secretion of LH, 2) 
      induce the preovulatory-like surge of LH, and 3) inhibit secretion of FSH in 
      ovariectomized (OVX) ewes. OVX ewes (n = 6) were administered intramuscularly 25 
      micrograms estradiol (E2), 12 mg propylpyrazoletriol (PPT; a subtype-selective 
      ESR1 agonist), 21 mg diaprylpropionitrile (DPN; a subtype-selective ESR2 
      agonist), or PPT + DPN. Like E2, administration of PPT, DPN, or combination of 
      the two rapidly decreased (P < 0.05) secretion of LH. Each agonist induced a 
      gradual, prolonged rise in secretion of LH after the initial inhibition, but 
      neither agonist alone nor the combined agonists was able to induce a "normal" 
      preovulatory-like surge of LH similar to that induced by E2. Compared with 
      E2-treated ewes, the beginning of the increase in secretion of LH occurred 
      earlier (P < 0.01) in DPN-treated ewes, later (P < 0.05) in PPT-treated ewes, and 
      at a similar interval in ewes receiving the combined agonist treatment. Like E2, 
      PPT decreased (P < 0.05) secretion of FSH, but the duration of suppression was 
      much longer in PPT-treated ewes. DPN did not alter secretion of FSH in this 
      study. Modulation of the number of GnRH receptors by PPT and DPN was examined in 
      primary cultures of ovine pituitary cells. In our hands, both PPT and DPN 
      increased the number of GnRH receptors, but the dose of DPN required to stimulate 
      synthesis of GnRH receptors was 10 times higher than that of PPT. We conclude 
      that in OVX ewes: 1) ESR1 and ESR2 mediate the negative feedback of E2 on 
      secretion of LH at the level of the pituitary gland, 2) ESR1 and ESR2 do not 
      synergize or antagonize the effects of each other; however, they do interact to 
      synchronize the beginning of the stimulatory effect of E2 on secretion of LH, 3) 
      ESR1 and ESR2 may mediate at least partially the positive feedback of E2 on LH 
      secretion by increasing the number of GnRH receptors, and 4) only ESR1 appears to 
      be involved in the negative feedback of E2 on secretion of FSH.
FAU - Arreguin-Arevalo, J Alejandro
AU  - Arreguin-Arevalo JA
AD  - Department of Biomedical Science, Colorado State University, Fort Collins, 
      Colorado 80523, USA.
FAU - Davis, Tracy L
AU  - Davis TL
FAU - Nett, Terry M
AU  - Nett TM
LA  - eng
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
DEP - 20070411
PL  - United States
TA  - Biol Reprod
JT  - Biology of reproduction
JID - 0207224
RN  - 0 (Estrogen Receptor alpha)
RN  - 0 (Estrogen Receptor beta)
RN  - 0 (Nitriles)
RN  - 0 (Phenols)
RN  - 0 (Pyrazoles)
RN  - 0 (Receptors, LHRH)
RN  - 0T83Y6JZPF (4,4',4''-(4-propyl-((1)H)-pyrazole-1,3,5-triyl) tris-phenol)
RN  - 4TI98Z838E (Estradiol)
RN  - 9002-67-9 (Luteinizing Hormone)
RN  - 9002-68-0 (Follicle Stimulating Hormone)
SB  - IM
MH  - Animals
MH  - Cells, Cultured
MH  - Drug Interactions
MH  - Estradiol/administration & dosage
MH  - Estrogen Receptor alpha/*agonists/physiology
MH  - Estrogen Receptor beta/*agonists/physiology
MH  - Feedback, Physiological
MH  - Female
MH  - Follicle Stimulating Hormone/*metabolism
MH  - Luteinizing Hormone/*metabolism
MH  - Nitriles/administration & dosage
MH  - Ovariectomy
MH  - Phenols
MH  - Pituitary Gland, Anterior/chemistry/drug effects/metabolism
MH  - Pyrazoles/administration & dosage
MH  - Receptors, LHRH/analysis/drug effects
MH  - *Sheep
EDAT- 2007/04/13 09:00
MHDA- 2007/09/26 09:00
CRDT- 2007/04/13 09:00
PHST- 2007/04/13 09:00 [pubmed]
PHST- 2007/09/26 09:00 [medline]
PHST- 2007/04/13 09:00 [entrez]
AID - biolreprod.107.060046 [pii]
AID - 10.1095/biolreprod.107.060046 [doi]
PST - ppublish
SO  - Biol Reprod. 2007 Aug;77(2):320-8. doi: 10.1095/biolreprod.107.060046. Epub 2007 
      Apr 11.