Ovarian hormones and fasting differentially regulate pituitary receptors for estrogen and gonadotropin-releasing hormone in rabbit female

• Published in: Microscopy research and technique 2014-03, Vol.77 (3), p.201-210
• Main Authors: Parillo, F., Zerani, M., Maranesi, M., Dall'Aglio, C., Galeati, G., Brecchia, G., Boiti, C., González-Mariscal, G.
• Format: Article
• Language: English
• Subjects: Animals; estradiol receptor; Estrogen Receptor alpha - genetics; Estrogen Receptor alpha - metabolism; Estrogens; Estrogens - physiology; Fasting; Female; Females; Gene Expression; GnRH receptor; Gonadotropin-Releasing Hormone - metabolism; Hormones; Ovariectomy; pituitary; Pituitary Gland - metabolism; Pituitary Gland, Anterior - metabolism; Priming; rabbit; Rabbits; Receptors; Receptors, LHRH - genetics; Receptors, LHRH - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism
• ISSN: 1059-910X; 1097-0029
• DOI: 10.1002/jemt.22328

ABSTRACT To investigate the mechanisms by which caloric restriction affects reproductive function in female rabbits, we measured, in animals intact or ovariectomized (OVX) estrogen‐primed and fed ad libitum or fasted for 48 h, the adenohypophysial expression of estrogen receptor‐alpha (ESR1) and gonadotropin releasing hormone receptor (GnRHR) and the dynamic secretion of LH following GnRH stimulation. Fasting increased the number of GnRHR‐immunoreactive (‐IR) cells in intact animals, whereas reduced the density of ESR1‐IR cells in OVX rabbits. Estrogen priming decreased the number of ESR1‐IR cells in fasted and OVX animals. Ovariectomy increased the number of ESR1‐IR cells in fed rabbits, but caused an opposite effect in both fed and fasted animals treated with estrogen. Fasting down regulated the mRNA levels for ESR1 and GnRHR. Estrogen‐priming reduced the abundance for ESR1 mRNA in both fed and fasted rabbits, and that for GnRHR in fasted rabbits. Ovariectomy halved ESR1 mRNA levels independently of treatment and feeding condition, whereas increased (P