Transactivation of a growth hormone (GH) promoter-luciferase construct in canine mammary cells.
Domest Anim Endocrinol
; 34(4): 403-10, 2008 May.
Article
en En
| MEDLINE
| ID: mdl-18262383
ABSTRACT
The gene encoding growth hormone (GH) is expressed not only in the pituitary but also in a variety of non-pituitary tissues. In the female dog, progestins are known to stimulate GH expression in the mammary gland. In order to investigate the regulation of the GH gene expression in the mammary gland, we transfected the canine mammary tumor cell line CMT-U229 with 3 different canine GH promoter-luciferase constructs. The constructs, varying in length between 252 bp and 673 bp, were transfected followed by an incubation for 4 h, 24 h and 48 h with cAMP, all-trans-retinoic acid (RA), 3,3',5-triiodothyronine (T3), 1,25-dihydroxy-vitamin D (VitD), progesterone and EGF. Promoter activity was stimulated by cAMP, T3 and RA whereas VitD clearly inhibited gene expression. However, despite the presence of nuclear and membrane receptors for progesterone, no direct effects of progesterone on promoter activity could be demonstrated. It is concluded that progesterone alone has no direct stimulatory effect on GH transcription. This finding is discussed in relation to the slow onset of progesterone-stimulated GH release in vivo and the absence of Pit-1 in canine mammary tissue.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Hormona del Crecimiento
/
Activación Transcripcional
/
Regiones Promotoras Genéticas
/
Perros
/
Luciferasas
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Glándulas Mamarias Animales
Límite:
Animals
Idioma:
En
Revista:
Domest Anim Endocrinol
Asunto de la revista:
ENDOCRINOLOGIA
/
MEDICINA VETERINARIA
Año:
2008
Tipo del documento:
Article
País de afiliación:
Países Bajos