scholarly journals Estradiol Negative Feedback Regulates Nocturnal Luteinizing Hormone and Follicle-Stimulating Hormone Secretion in Prepubertal Female Rhesus Monkeys

2004 ◽  
Vol 89 (8) ◽  
pp. 3973-3978 ◽  
Author(s):  
M. E. Wilson ◽  
J. Fisher ◽  
K. Chikazawa
Keyword(s):  
Luteinizing Hormone ◽  
Negative Feedback ◽  
Rhesus Monkeys ◽  
Follicle Stimulating Hormone ◽  
Hormone Secretion ◽  
Female Rhesus ◽  
Stimulating Hormone

Negative feedback effects of oestradiol-17ß on luteinizing hormone in female rhesus monkeys under different seasonal conditions

1985 ◽  
Vol 108 (1) ◽  
pp. 31-35
Author(s):  
J. G. Herndon ◽  
M. S. Blank ◽  
D. R. Mann ◽  
D. C. Collins ◽  
J.J. Turner
Keyword(s):  
Luteinizing Hormone ◽  
Breeding Season ◽  
Negative Feedback ◽  
Rhesus Monkeys ◽  
Feedback Effects ◽  
Female Rhesus ◽  
Time Of Year

Abstract. Suppression of luteinizing hormone (LH) by sc implanted oestradiol-17ß (E2) pellets was examined in 4 ovariectomized female rhesus monkeys during the breeding season, the non-breeding season and during the transition between the breeding and non-breeding season. Immunoreactive LH was suppressed to 58, 78 and 75% of untreated levels for the respective seasonal conditions. Bioactive LH was suppressed to 29, 49 and 33% of baseline. Bioactive LH (determined by testoster-one release from rat interstital cells) was significantly correlated (r = 0.84) with immunoactive LH from the same samples. It is concluded that E2 treatment of ovariectomized female rhesus monkeys results in suppressed levels of LH, regardless of the time of year.

Responses of luteinizing hormone (LH) and follicle-stimulating hormone levels to exogenous gonadotropin-releasing hormone during the estrogen-induced LH surge in the ovariectomized rhesus monkey

1989 ◽  
Vol 67 (2) ◽  
pp. 135-139 ◽  
Author(s):  
Richard F. Weick ◽  
Vaclav Pitelka ◽  
David L. Thompson
Keyword(s):  
Luteinizing Hormone ◽  
Rhesus Monkey ◽  
Negative Feedback ◽  
Follicle Stimulating Hormone ◽  
Gonadotropin Releasing Hormone ◽  
Gonadotropin Secretion ◽  
Lh Surge ◽  
Releasing Hormone ◽  
Acute Response ◽  
Stimulating Hormone

Experiments were performed to study the responsiveness of the pituitary to gonadotropin-releasing hormone (GnRH) during the dynamic changes in gonadotropin secretion associated with the estrogen-induced luteinizing hormone (LH) surge in the ovariectomized (OVX) rhesus monkey. Silastic capsules filled with estradiol-17-β were implanted subcutaneously in ovariectomized rhesus monkeys, resulting in an initial lowering of circulating LH and follicle-stimulating hormone (FSH) concentrations followed by an LH–FSH surge. GnRH was injected intravenously just before estrogen implantation, during the negative feedback response and during the rising, the peak, and the declining phases of the LH surge. The LH and FSH responses during the negative feedback phase were as large as those before estrogen treatment (control responses). During the rising phase of the LH surge, the acute response to GnRH injection did not differ significantly from the control response, but the responses 60 and 120 min after injection were somewhat increased. During the declining phase of the LH surge, the pituitary was not responsive to exogenous GnRH, although LH probably continued to be secreted at this time since the LH surge decreased more slowly than predicted by the normal rate of disappearance of LH in the monkey. We conclude that an increased duration of response to GnRH may be an important part of the mechanism by which estrogen induces the LH surge, but we do not see evidence of increased sensitivity of the pituitary to GnRH as an acute releasing factor at that time.Key words: LH surge, GnRH, FSH, ovariectomized monkey.

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