The effect of LH-RH administration on LH release in the female rabbit

Carlson, John C.; Perrin, Donald G.

doi:10.1530/jrf.0.0560175

Cited by 7 publications

(5 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, other pathways of GnRHR signal transduction might be involved in our in vivo model (Cheng and Leung, ; Gieske et al, ), similar to what Weiss et al () described for an in vitro system. By contrast, in OVX rabbits, neither fasting nor E2 priming modified the GnRH‐stimulated LH release, in agreement with previous results by Carlson and Perrin (). Thus, our findings point to complex feedback interactions between the availability of nutritional metabolites and ovarian hormones, including E2.…”

Section: Discussionsupporting

confidence: 92%

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

Parillo

Zerani

Maranesi

et al. 2013

Microsc. Res. Tech.

View full text Add to dashboard Cite

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 < 001) that for GnRHR in estrogen-primed rabbits. In all rabbits, an LH surge occurred 30 min after GnRH injection but the lowest levels were found in intact fasted rabbits and the highest in fasted, estrogen-primed animals. The LH profile was similar in intact and OVX rabbits and neither fasting nor estrogen priming modified it. In conclusion, fasting differentially modifies the ESR1 and GnRHR expression in the pituitary, depending on the presence of gonadal hormones, indicating complex interactions between metabolic signals and ovarian steroids.

show abstract

Section: Discussionsupporting

confidence: 92%

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

Parillo

Zerani

Maranesi

et al. 2013

Microsc. Res. Tech.

View full text Add to dashboard Cite

show abstract

“…The same profile was described for oestrogen-treated intact rabbits after mating (Kanematsu et al, 1974;Goodman & Neill, 1976) or after a single LHRH injection (YoungLai, 1977). In rabbits the release of LH after the constant infusion of LHRH was higher in oestradiol benzoate-treated intact and ovariectomized females (Carlson & Perrin, 1979). During constant infusion of LHRH, the pituitary cells of the female rat were able to secrete LH in a biphasic manner (Loughlin et al, 1984).…”

Section: Discussionmentioning

confidence: 99%

Seasonal variations in the pituitary response to LHRH in the brown hare (Lepus europaeus)

Caillol¹,

Meunier²,

Mondain-Monval³

et al. 1986

Reproduction

View full text Add to dashboard Cite

In the brown hare, fertile mating takes place from the beginning of December to September. Pituitary and ovarian response to a monthly i.v. injection of 5 micrograms LHRH was studied from September 1983 to October 1984 in 2 groups of 6 hares. The basal concentrations of LH remained undetectable until the end of January, rose from 0.23 +/- 0.14 ng/ml from February to a maximum of 1.44 +/- 0.57 ng/ml in July. LHRH injection was always followed by a release of LH. Between September and December, the LH value peaked 15 min after injection and returned to basal concentrations 2 h later. From January, this pattern altered and a second peak of LH appeared 2 h after injection. Peak levels 15 min after LHRH were around 10 ng/ml between September and December, increased from 47.0 +/- 8.0 ng/ml in January to 106 +/- 33 ng/ml in July and decreased in August (69.4 +/- 10.6 ng/ml). The values of the second peak rose from 11.0 +/- 2.2 ng/ml in January to 90.6 +/- 12.4 ng/ml between March and July and decreased in August (24.5 +/- 5.1 ng/ml). The LH surge induced by LHRH was always followed by a transient rise in progesterone. During the breeding season, this progesterone secretion increased considerably. Ovulation was possible between January and August and the number of ovulating females was maximum between March and July. The amount and duration of progesterone secretion during the resulting pseudopregnancies increased during the breeding season.

show abstract

“…A similar finding has been obtained in pregnant rabbits during the whole pregnancy (Mills & Gerardot, 1984), leading to the conclusion that progesterone probably blocked LHRH release in response to mating (Hilliard et ai, 1971). Furthermore, in rabbits, the LH response to LHRH was reduced during pregnancy or pseudopregnancy (Hilliard etai, 1971;Carlson & Perrin, 1979). However, in brown hares (Martinet, 1980), as in rabbits (Stormshak & Casida, 1965), the ovary remains able to respond to an injection of human chorionic gonadotrophin by an ovulation during the whole pregnancy.…”

Section: Discussionmentioning

confidence: 99%

Gonadotrophins and sex steroids during pregnancy and natural superfoetation in captive brown hares (Lepus europaeus)

Caillol¹,

Mondain-Monval²,

Rossano³

1991

Reproduction

View full text Add to dashboard Cite

In brown hares, which are induced ovulators, sexual behaviour occurs episodically at the beginning of pregnancy. From Day 34 (length of pregnancy is 41 days), the frequency of sexual chases followed by mating, ovulation and fertilization increased and 59% of pregnant females presented a natural superfoetation. The pattern of circulating luteinizing hormone (LH), follicle-stimulating hormone (FSH), oestradiol and progesterone was studied in 13 pregnant females left permanently with a male, and in 10 females isolated from males around Day 20 of pregnancy. In the 2 groups FSH concentrations were high at the beginning and end of pregnancy. All females presented a peak value of FSH in the last 4 days of pregnancy, regardless of mating stimuli. This peak value was higher for females left permanently with a male than for isolated ones. Oestradiol concentrations fluctuated between 20 and 100 pg/ml, without any clear correlation with sexual behaviour, stage of pregnancy or profiles of other hormones. Prepartum matings occurred when progesterone values were still greater than 50 ng/ml; they were followed by a transient rise in LH and by a periovulatory progesterone secretion, with values above 100 ng/ml in the morning after mating. Such modifications of LH and progesterone were not detected before Day 34, suggesting that mating stimuli are not able to induce an LH surge at the beginning of pregnancy. After Day 34, mating can induce an LH surge, ovulation and superfoetation.

show abstract

The effect of LH-RH administration on LH release in the female rabbit

Cited by 7 publications

References 17 publications

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

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

Seasonal variations in the pituitary response to LHRH in the brown hare (Lepus europaeus)

Gonadotrophins and sex steroids during pregnancy and natural superfoetation in captive brown hares (Lepus europaeus)

Contact Info

Product

Resources

About