EFFECT OF NEONATAL ADMINISTRATION OF STEROIDS OR GONADECTOMY UPON OESTRADIOL-INDUCED LUTEINIZING HORMONE RELEASE IN RATS OF BOTH SEXES

1980 ◽  
Vol 85 (1) ◽  
pp. 69-74 ◽  
Author(s):  
F. GOGAN ◽  
I. A. BEATTIE ◽  
M. HERY ◽  
E. LAPLANTE ◽  
C. KORDON
Keyword(s):  
Luteinizing Hormone ◽  
Sexual Differentiation ◽  
Female Rats ◽  
Male Rats ◽  
Ovariectomized Rats ◽  
Hormone Release ◽  
Adult Rats ◽  
Luteinizing Hormone Release ◽  
Neonatal Administration ◽  
Lh Secretion

SUMMARY Implantation of oestradiol into adult rats of both sexes induced different patterns of LH secretion depending on the time at which gonadectomy or testosterone injection were performed. Castration 2 h after birth allowed an LH peak to occur daily at 18.00 h, but its amplitude was lower than that of adult gonadectomized female rats treated with oestradiol. Castration 24 h after birth elicited two kinds of response; a circadian discharge of LH lower than that of male rats gonadectomized 2 h after birth or a steady low level of LH. The LH rhythmicity induced by implantation of oestradiol was not seen after castration at 8 weeks of age. Neonatal administration of testosterone to female rats prevented the LH peak induced by oestradiol that was seen in adult ovariectomized rats. Neonatal or adult ovariectomy did not interfere with the rhythmical response of LH after implantation of oestradiol. Thus, it is concluded that sexual differentiation of the hypothalamus is primarily of masculine origin.

scholarly journals Central estrogen action sites involved in prepubertal restraint of pulsatile luteinizing hormone release in female rats

2015 ◽  
Vol 61 (4) ◽  
pp. 351-359 ◽  
Author(s):  
Yoshihisa UENOYAMA ◽  
Akira TANAKA ◽  
Kenji TAKASE ◽  
Shunji YAMADA ◽  
Vutha PHENG ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Female Rats ◽  
Hormone Release ◽  
Estrogen Action ◽  
Luteinizing Hormone Release

scholarly journals Effect of androgen on Kiss1 expression and luteinizing hormone release in female rats

2017 ◽  
Vol 233 (3) ◽  
pp. 281-292 ◽  
Author(s):  
Kinuyo Iwata ◽  
Yuyu Kunimura ◽  
Keisuke Matsumoto ◽  
Hitoshi Ozawa
Keyword(s):  
Luteinizing Hormone ◽  
Arcuate Nucleus ◽  
Female Rats ◽  
Hormone Release ◽  
Lh Surge ◽  
Continuous Release ◽  
Ovulatory Dysfunction ◽  
Lh Release ◽  
Gonadotrophin Releasing Hormone ◽  
Lh Secretion

Hyperandrogenic women have various grades of ovulatory dysfunction, which lead to infertility. The purpose of this study was to determine whether chronic exposure to androgen affects the expression of kisspeptin (ovulation and follicle development regulator) or release of luteinizing hormone (LH) in female rats. Weaned females were subcutaneously implanted with 90-day continuous-release pellets of 5α-dihydrotestosterone (DHT) and studied after 10 weeks of age. Number of Kiss1-expressing cells in both the anteroventral periventricular nucleus (AVPV) and arcuate nucleus (ARC) was significantly decreased in ovary-intact DHT rats. Further, an estradiol-induced LH surge was not detected in DHT rats, even though significant differences were not observed between DHT and non-DHT rats with regard to number of AVPV Kiss1-expressing cells or gonadotrophin-releasing hormone (GnRH)-immunoreactive (ir) cells in the presence of high estradiol. Kiss1-expressing and neurokinin B-ir cells were significantly decreased in the ARC of ovariectomized (OVX) DHT rats compared with OVX non-DHT rats; pulsatile LH secretion was also suppressed in these animals. Central injection of kisspeptin-10 or intravenous injection of a GnRH agonist did not affect the LH release in DHT rats. Notably, ARC Kiss1-expressing cells expressed androgen receptors (ARs) in female rats, whereas only a few Kiss1-expressing cells expressed ARs in the AVPV. Collectively, our results suggest excessive androgen suppresses LH surge and pulsatile LH secretion by inhibiting kisspeptin expression in the ARC and disruption at the pituitary level, whereas AVPV kisspeptin neurons appear to be directly unaffected by androgen. Hence, hyperandrogenemia may adversely affect ARC kisspeptin neurons, resulting in anovulation and menstrual irregularities.

The Role of Neural Inputs from the Posterior Arcuate Nucleus in Pulsatile Luteinizing Hormone Release in Ovariectomized Rats.

2010 ◽  
Vol 83 (Suppl_1) ◽  
pp. 575-575
Author(s):  
Yoshihisa Uenoyama ◽  
Saya Watanabe ◽  
Kinuyo Iwata ◽  
Satoshi Ohkura ◽  
Kei-ichiro Maeda ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Arcuate Nucleus ◽  
Ovariectomized Rats ◽  
Hormone Release ◽  
Luteinizing Hormone Release

Role of α-Adrenergic Mechanism in Regulating Tonic Luteinizing Hormone Release in Conscious Ovariectomized Rats*

Endocrinology ◽  
1981 ◽  
Vol 108 (4) ◽  
pp. 1272-1275 ◽  
Author(s):  
F. KINOSHITA ◽  
Y. NAKAI ◽  
H. KATAKAMI ◽  
Y. KATO ◽  
H. IMURA
Keyword(s):  
Luteinizing Hormone ◽  
Ovariectomized Rats ◽  
Hormone Release ◽  
Luteinizing Hormone Release ◽  
Adrenergic Mechanism

EFFECTS OF NALOXONE ON LUTEINIZING HORMONE AND PROLACTIN IN SERUM OF RATS

1980 ◽  
Vol 85 (2) ◽  
pp. 307-315 ◽  
Author(s):  
M. S. BLANK ◽  
A. E. PANERAI ◽  
H. G. FRIESEN
Keyword(s):  
Female Rats ◽  
Male Rats ◽  
Ovariectomized Rats ◽  
Serum Prolactin ◽  
Immature Female ◽  
Subcutaneous Injections ◽  
Serum Lh ◽  
Opiate Peptides ◽  
Lh Release ◽  
Lh Secretion

The effects of subcutaneous injections of the opiate antagonist naloxone on the tonic and phasic secretion of prolactin and LH were studied in rats. During development, resting levels of prolactin in serum were decreased by naloxone (2·5 mg/kg body wt) on days 24,45 and 50 in female rats and on days 28,45 and 50 in male rats. In the adult, naloxone (2·5 mg/kg body wt) decreased basal levels of serum prolactin in male rats and levels during oestrus in female rats. In 25-day-old female rats, serum LH rose from resting levels within 7·5 min of naloxone administration (2·5 mg/kg body wt) and returned to pretreatment levels by 30 min, while prolactin fell by 7·5 min and remained low for as long as 60 min after treatment. Furthermore, a tenfold lower dose of naloxone (0·25 mg/kg body wt) did not raise basal levels of serum LH but still decreased resting levels of serum prolactin in immature female rats (24 days old). The effect of naloxone (2·5 mg/kg body wt) on phasic LH release was studied in 29-day-old immature female rats primed on day 27 with pregnant mare serum gonadotrophin (PMSG). In these PMSG-treated rats the onset of the prolactin surge was blunted by naloxone while it had no effect on phasic LH release. Naloxone (5 mg/kg body wt) also induced a rise in levels of serum LH in ovariectomized rats and, if administered with morphine, it reversed the short-term inhibition of LH secretion caused by morphine. However, naloxone was ineffective after pretreatment with oestradiol benzoate. These findings suggest that the responses of serum LH and prolactin to naloxone were dissociated and that oestrogens and opiate peptides may have interacted to regulate secretion of LH.

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