The effects of the potent GnRH antagonist [Ac-D-NAL(2)1, 4F-D-Phe2, D-Trp3, D-Arg6]-GnRH (GnRH-A), on ovulation in mature rats and rabbits and on serum LH and FSH levels in ovariectomized rats, rabbits and mice were investigated. Dose-response studies showed that 1 microgram (4 micrograms/kg) of GnRH-A was sufficient to inhibit ovulation completely in cycling rats, while 500 micrograms (135 micrograms/kg) were required to inhibit mating induced ovulation in 8 of 11 rabbits. Two of the 3 rabbits which ovulated in spite of the antagonist treatment had delayed LH surges. The mean LH peak of these 3 rabbits was significantly (p less than 0.001) lower than that of controls. Pituitary response to GnRH-A, as measured by plasma gonadotropin levels following GnRH-A treatment in ovariectomized rabbits, rats and mice showed highest sensitivity of the rat to the inhibitory effects of the antagonist. Serum FSH levels were slightly suppressed in rats, but remained undiminished in rabbits and mice. The difference in the response of the three species to the antipituitary effects of GnRH-A is most likely due to differences in the affinity of the pituitary GnRH receptor to the antagonist.

Species differences in the sensitivity to a GnRH antagonist / P. Limonta, C. W. Bardin, A. Ladishenskaya, S. Pavlou, K. Sundaram, R. B. Thau. - In: CONTRACEPTION. - ISSN 0010-7824. - 32:1(1985 Jul), pp. 75-85.

Species differences in the sensitivity to a GnRH antagonist

P. Limonta
Primo
;
1985

Abstract

The effects of the potent GnRH antagonist [Ac-D-NAL(2)1, 4F-D-Phe2, D-Trp3, D-Arg6]-GnRH (GnRH-A), on ovulation in mature rats and rabbits and on serum LH and FSH levels in ovariectomized rats, rabbits and mice were investigated. Dose-response studies showed that 1 microgram (4 micrograms/kg) of GnRH-A was sufficient to inhibit ovulation completely in cycling rats, while 500 micrograms (135 micrograms/kg) were required to inhibit mating induced ovulation in 8 of 11 rabbits. Two of the 3 rabbits which ovulated in spite of the antagonist treatment had delayed LH surges. The mean LH peak of these 3 rabbits was significantly (p less than 0.001) lower than that of controls. Pituitary response to GnRH-A, as measured by plasma gonadotropin levels following GnRH-A treatment in ovariectomized rabbits, rats and mice showed highest sensitivity of the rat to the inhibitory effects of the antagonist. Serum FSH levels were slightly suppressed in rats, but remained undiminished in rabbits and mice. The difference in the response of the three species to the antipituitary effects of GnRH-A is most likely due to differences in the affinity of the pituitary GnRH receptor to the antagonist.
Animals; Luteinizing Hormone; Pituitary Gland; Mice; Rabbits; Follicle Stimulating Hormone; Rats; Rats, Inbred Strains; Ovulation; Gonadotropin-Releasing Hormone; Ovariectomy; Species Specificity; Female
Settore BIO/13 - Biologia Applicata
Article (author)
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/182726
Citazioni
  • ???jsp.display-item.citation.pmc??? 1
  • Scopus 3
  • ???jsp.display-item.citation.isi??? 5
social impact