In Vivo and in Vitro Effects of Substance P and Neurotensin on Gonadotropin and Prolactin Release*

Vijayan, E.; McCann, Samuel M.

doi:10.1210/endo-105-1-64

Cited by 271 publications

(141 citation statements)

References 14 publications

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“…Similar to the TRH receptor, NK3R, a receptor for NKB, is a member of the Gq protein-coupled receptor family that mainly stimulates family, modulates several anterior pituitary hormones [23]. Substance P also directly stimulates PRL release from rat pituitary cells [33]. There has been a speculation that the action of tachykinins on PRL may be exerted at the hypothalamus as well as at the anterior pituitary level.…”

Section: Discussionmentioning

confidence: 99%

Role of Neurokinin B and Dynorphin A in pituitary gonadotroph and somatolactotroph cell lines

et al. 2012

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Section: Discussionmentioning

confidence: 99%

Role of Neurokinin B and Dynorphin A in pituitary gonadotroph and somatolactotroph cell lines

et al. 2012

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“…SP-immunoreactive fibers were found in GnRH neurons in humans and rats [35,36]. Earlier studies have demonstrated that Tac1 products such as SP and NPK stimulated [37,38], suppressed [39,40] or did not affect LH secretion in rats. On the other hand, NKB neurons project their fibers to the external zone in the median eminence in rodents and ruminants [12,13,[41][42][43].…”

mentioning

confidence: 89%

Involvement of Neurokinin Receptors in the Control of Pulsatile Luteinizing Hormone Secretion in Rats

et al. 2011

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Abstract. It has recently been shown that neurokinin B, a tachykinin, is associated with GnRH pulse generation in sheep and goats. The aim of the present study was to clarify the role of tachykinin receptors in the control of LH secretion in rats. To this end, we evaluated the effect of CS-003, an antagonist for all three neurokinin receptors (NK1, NK2 and NK3 receptors), on pulsatile LH secretion in both sexes of rats with different routes of administration. Both oral and third ventricular administration of CS-003 suppressed LH secretion in both sexes of gonadectomized animals. Furthermore, intact male rats with oral administration of CS-003 showed decreased serum testosterone levels, which might be due to suppressed LH secretion. None of the three subtype-specific neurokinin receptor antagonists showed a significant effect on LH secretion in ovariectomized rats when each antagonist was singly administered. The present results suggest that neurokinins play a role in the control of pulsatile GnRH/LH secretion via multiple neurokinin receptors in both male and female rats. Key words: Luteinizing hormone, Neurokinin, Rat, Receptor (J. Reprod. Dev. 57: [409][410][411][412][413][414][415] 2011) ulsatile gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) release is indispensable for regulation of gonadal functions, such as folliculogenesis, spermatogenesis and steroidogenesis, in rodents [1], ruminants [2,3] and primates [4]. The mechanism generating GnRH/LH pulses, called the GnRH pulse generator, has been suggested to be localized in the hypothalamus [5]. Recent studies have revealed that kisspeptin neurons located in the hypothalamus play a central role in regulating GnRH release [6,7]. Kisspeptin neurons have two populations in the hypothalamus [8]: One is located in the hypothalamic arcuate nucleus (ARC), and the other is located in the anteroventral periventricular nucleus (AVPV). Of these two populations, the AVPV kisspeptin neurons have been reported to be involved in the regulation of GnRH/LH surge [9,10]. On the other hand, the role of ARC kisspeptin neurons is still unclear, but several lines of evidence suggest that the population is associated with GnRH pulse generation [11].Recent studies have shown an interesting and essential aspect of the ARC kisspeptin neurons. Most kisspeptin neurons have neurokinin B (NKB) and dynorphin (Dyn) in sheep [12], goats [13] and rodents [14], and thus the neurons have been called KNDy neurons [15]. Colocalization of those three neuropeptides in the ARC neurons might be associated with GnRH pulse generation. It has recently been reported that mutations of genes encoding NKB and its receptor are associated with gonadotropin deficiency in humans [16], and central administration of a selective NKB receptor agonist stimulates LH secretion in sheep [17] and monkeys [18]. These reports indicate the significance of NKB/NK3 signaling in GnRH/gonadotropin release in these animal species. In addition to neurokinin B, nor-BNI, a κ-opioid receptor antagonist (KOR), rev...

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“…The difference in the results is probably related to the difference in the injection site. Such differential effects of neuropeptides on LH secretion depending upon the site of microinjection in the brain were also found in the case of neurotensin; the injection of neurotensin into the MPO did not affect pulsatile LH secretion in OVX rats [13] but that into the third ventricle inhibited the LH secretion [14]. Intracerebroventricularly injected LHRH probably acts on hypothalamic areas other than the MPO; for example on the mediobasal hypothalamus [5,6], to inhibit its own secretion in OVX rats.…”

Section: Discussionmentioning

confidence: 66%

Microinjection of LHRH and Its Antagonistic Analog into the Medial Preoptic Area Does Not Affect Pulsatile Secretion of LH in Ovariectomized Rats.

et al. 1994

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Abstract. To gain a better understanding of the existence of an ultra-short feedback mechanism controlling LHRH secretion in the medial preoptic area (MPO), we examined the effects of microinjections of LHRH or the LHRH antagonist into the MPO on pulsatile secretion of LH in ovariectomized rats and on the surge of LH secretion in proestrous rats. Neither the injection of 10 ng LHRH nor 100 ng its antagonist into the MPO had any effect on pulse frequency or the mean LH concentration in ovariectomized rats. The injection of 100 ng LHRH antagonist or 10 ng LHRH delayed or advanced, respectively, the LH surge in proestrous rats. Taking these results together with our previous report, the present study indicates that 1) endogenous LHRH in the MPO is involved in the ultra-short feedback regulation of LHRH release and 2) the ultra-short positive feedback mechanism in the MPO acts at the time of the proestrous LH surge but not under a hormonal milieu as in ovariectomized rats. Key words; LHRH, Preoptic area, Feedback, LH, Ovariectomy, LHRH antagonist (Endocrine Journal 41: 559-563,1994) IT HAS BEEN reported that intraventricular injection of LHRH or LHRH agonist reduces the secretion of LHRH [1] and thus the secretion of LH is decreased in ovariectomized (OVX) rats [2, 3] and ewes [4], implying the existence of an ultra-short negative feedback mechanism for the control of LHRH secretion. In addition, in vitro studies have suggested that the neural structure that is involved in the mechanism is in the mediobasal hypothalamus including the median eminence [5,6].On the other hand, we have shown [7] that LHRH injected into the medial preoptic area (MPO) potentiates the surge of LH secretion in OVX estrogen-primed and proestrous rats, suggesting the existence of an ultra-short positive feedback mechanism in the MPO, instead of a negative one as reported by others. The discrepancies between our results and those of others might be due to differences of the influence of gonadal steroids or the site of injection. We therefore examined the effect of the microinjection of LHRH or LHRH antagonist into the MPO on the pulsatile LH secretion in OVX rats. We also examined the effect of LHRH antagonist and LHRH on the LH surge in proestrous rats and compared it with the effect in OVX rats. Materials and MethodsFemale Wistar-Imamichi rats were obtained from the Animal Reproduction Research (Omiya, Japan) at 7-8 weeks of age and were maintained under controlled lighting conditions (lights on 0700 h-1900 h), with food and water available ad

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In Vivo and in Vitro Effects of Substance P and Neurotensin on Gonadotropin and Prolactin Release*

Cited by 271 publications

References 14 publications

Role of Neurokinin B and Dynorphin A in pituitary gonadotroph and somatolactotroph cell lines

Role of Neurokinin B and Dynorphin A in pituitary gonadotroph and somatolactotroph cell lines

Involvement of Neurokinin Receptors in the Control of Pulsatile Luteinizing Hormone Secretion in Rats

Microinjection of LHRH and Its Antagonistic Analog into the Medial Preoptic Area Does Not Affect Pulsatile Secretion of LH in Ovariectomized Rats.

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