scholarly journals Estrogen Modulates Effects of Glutamate on In Vitro Gonadotropin-Releasing Hormone Release by Altering Nitric Oxide Action in Female Rats.

1998 ◽  
Vol 44 (4) ◽  
pp. 399-405 ◽  
Author(s):  
Shinji TSUKAHARA ◽  
Hiroko TSUKAMURA ◽  
Kei-Ichiro MAEDA
Keyword(s):  
Nitric Oxide ◽  
Gonadotropin Releasing Hormone ◽  
Female Rats ◽  
Hormone Release ◽  
Releasing Hormone

Estrogen stimulates gonadotropin-releasing hormone release from rat hypothalamus independently through catecholamine and histamine in vitro

1989 ◽  
Vol 120 (5) ◽  
pp. 644-648 ◽  
Author(s):  
Shirou Ohtsuka ◽  
Takamichi Nishizaki ◽  
Keiichi Tasaka ◽  
Akira Miyake ◽  
Osamu Tanizawa ◽  
...  
Keyword(s):  
Bovine Serum Albumin ◽  
Gonadotropin Releasing Hormone ◽  
Female Rats ◽  
Hormone Release ◽  
Mediobasal Hypothalamus ◽  
Releasing Hormone ◽  
Gnrh Release ◽  
Perifusion System ◽  
Made In

Abstract. Estradiol is known to stimulate gonadotropin-releasing hormone release from the rat mediobasal hypothalamus. Studies were made in an in vitro perifusion system on whether catecholamine and/or histamine was involved in estradiol-induced GnRH release. Normal cycling female rats were decapitated in diestrus II and their medio-basal hypothalami were combined and, perifused with Earl's balanced salt solution containing 0.01% bovine serum albumin bubbled with 95% O2 and 5% CO2. The levels of norepinephrine, dopamine, and histamine and of GnRH in the effluent were measured by HPLC and radioimmunoassay, respectively. Administration of 10−6 mol/l estradiol resulted in releases of norepinephrine, dopamine, histamine and GnRH at levels of 98, 70, 91 and 288%, respectively, of initial values. Administration of 10−6 mol/l norepinephrine or dopamine resulted in no increase in histamine release, and administration of 10−6 mol/l histamine did not increase release of norepinephrine or dopamine. These data suggest that estradiol stimulates the releases of GnRH, catecholamine and histamine from the rat medio-basal hypothalamus, and that it increases GnRH release independently through catecholamine and histamine. As we found previously that norepinephrine or histamine stimulates GnRH release from the mediobasal hypothalamus, we conclude that estradiol stimulates releases of norepinephrine and histamine, resulting in GnRH release from the medio-basal hypothalamus.

Relation of attenuated proestrous luteinizing hormone surges in middle-aged female rats to in vitro pituitary gonadotropin-releasing hormone responsiveness

1994 ◽  
Vol 130 (5) ◽  
pp. 540-544 ◽  
Author(s):  
Aurelia N Brito ◽  
Timothy E Sayles ◽  
Richard J Krieg ◽  
Dennis W Matt
Keyword(s):  
Luteinizing Hormone ◽  
Gonadotropin Releasing Hormone ◽  
Female Rats ◽  
Aged Rats ◽  
Middle Aged ◽  
Releasing Hormone ◽  
Young Females ◽  
Pituitary Gonadotropin ◽  
Hormone Responsiveness

Brito AN, Sayles TE, Krieg Jr RJ, Matt DW. Relation of attenuated proestrous luteinizing hormone surges in middle-aged female rats to in vitro pituitary gonadotropin-releasing hormone responsiveness. Eur J Endocrinol 1994;130:540–4. ISSN 0804–4643 Prior to the cessation of regular cyclicity, middle-aged rats display pre-ovulatory luteinizing hormone (LH) surges of reduced magnitude. The present study was designed to identify whether middle-aged female rats with attenuated proestrous LH surges have alterations in pituitary responsiveness to gonadotropin-releasing hormone (GnRH). Young (4 months old) and middle-aged (10–12 months old) regularly cycling females were catheterized and sampled on proestrus to characterize their LH surge profiles. On the next proestrus (12.00 h), pituitaries were perifused individually and exposed to three pulses of GnRH (30 nmol/l). The patterns of the proestrous LH surges revealed that 12 of 22 middle-aged rats had attenuated surges (< 7 μg/l) while the remaining 10 middle-aged females had surges that were similar to those of young rats. Pituitaries perifused on the next proestrus showed similar basal LH release among the middle-aged and young females. However, the LH secretory rates following the second and third administration of GnRH, as well as the overall GnRH-stimulated LH secretory rates, were significantly decreased in middle-aged females with previously attenuated LH surges as compared to those from the young proestrous rats. In contrast, middle-aged rats with normal LH surges had pituitary LH responses that were no different from those of young females. These results indicate that a decrease in pituitary LH responsiveness to GnRH is only apparent in middle-aged rats that display attenuated proestrous LH surges. Dennis W Matt. Department of Obstetrics and Gynecology, Medical College of Virginia, Box 980034, Richmond, VA 23298, USA

Effects of Ghrelin upon Gonadotropin-Releasing Hormone and Gonadotropin Secretion in Adult Female Rats: In vivo and in vitro Studies

2005 ◽  
Vol 82 (5-6) ◽  
pp. 245-255 ◽  
Author(s):  
Rafael Fernández-Fernández ◽  
Manuel Tena-Sempere ◽  
Víctor M. Navarro ◽  
María L. Barreiro ◽  
Juan M. Castellano ◽  
...  
Keyword(s):  
Adult Female ◽  
Gonadotropin Releasing Hormone ◽  
In Vitro Studies ◽  
Female Rats ◽  
Gonadotropin Secretion ◽  
Releasing Hormone
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