Luteinizing hormone secretion as influenced by age and estradiol in the prepubertal gilt.
Anim Reprod Sci
; 122(3-4): 324-7, 2010 Dec.
Article
en En
| MEDLINE
| ID: mdl-21055887
The aim of this study was to determine if there is an age related reduction in the sensitivity of the negative feedback action of 17ß-estradiol (estradiol) on luteinizing hormone (LH) secretion in the prepubertal gilt. Ovariectomized gilts at 90 (n=12), 150 (n=11) or 210 (n=12) days of age received estradiol benzoate (EB) osmotic pump implants 6/group and the remaining animals received vehicle control (C) implants except for 150-day C (n=5) on Day 0. On Day 10 blood samples were collected every 15 min for 8h and serum LH and estradiol concentrations were measured. Serum estradiol concentrations averaged 5 ± 1, 5 ± 1 and 7 ± 2 pg/ml for the 90-, 150- and 210-day-old gilts implanted with estradiol, respectively, whereas, serum estradiol concentrations was undetectable in C gilts. Mean serum LH concentrations, basal LH concentrations and serum LH pulse amplitude were less in EB-treated gilts at all ages compared to control animals. In contrast, LH pulse frequency initially was less in EB-treated gilts but subsequently increased (P<0.04) with age (from 0.8 ± 0.2 at 90 days to 5.2 ± 0.2/8h at 210 days), and at 210 days of age the pulse frequency was similar to C gilts. These results demonstrate an age related reduction in the sensitivity to the negative feedback action of estradiol on LH secretion and support the idea that the gilt conforms to the gonadostat hypothesis.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Porcinos
/
Envejecimiento
/
Hormona Luteinizante
/
Estradiol
Límite:
Animals
Idioma:
En
Revista:
Anim Reprod Sci
Año:
2010
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Países Bajos