首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The effect of the gonadotropin-releasing hormone (LRH) and thyrotropin-releasing hormone (TRH) on the blood levels of LH, FSH and TSH, and LHbeta- and alpha-subunit have been studied in 4 normal subjects during the first 20 min after administration of these releasing hormones. Increases in serum immunoreactive LH, LHbeta and alpha-subunit were seen in all subjects after LRH (100 mug iv) but in all subjects the rise in LH was preceded by a rise in alpha-subunit. All subjects showed an increase in TSH and 3 of the 4 subjects a rise in alpha-subunit after TRH (200 mug) but the alpha-subunit responses were smaller and less consistent than after LRH. Levels of LHbeta remained unchanged after TRH. The results demonstrate that the immunoreactive alpha-subunit of the pituitary glycoprotein hormones can be released independently of the intact hormones and that release occurs in response to the same releasing hormones, LRH and TRH, that release the intact hormones.  相似文献   

2.
Intracerebroventricular (icv) administration of the nonapeptide oxytocin (OXT) increases sexual receptivity in female rats. The medial preoptic area (MPOA) appeared to be the most sensitive brain area to the facilitative effects of OXT. Bilateral infusions of 100 ng of OXT into the MPOA significantly elevated lordosis quotients in overiectomized (OVX), estrogen-treated rats. This dose of OXT was ineffective when infused icv or into the ventromedial hypothalamus, mesencephalic central gray, or ventral tegmental area. A 500-ng dose of OXT significantly elevated lordosis responding when infused icv, corresponding with our previous findings. Mounting by males significantly increased immunoreactive levels of OXT and decreased the number of OXT immunostaining cells in the MPOA of sexually receptive rats pretreated with estrogen and progesterone. The MPOA is a primary site of the OXT facilitation of sexual receptivity where OXT may be released during mating. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

3.
The effects were studied of follicle stimulating hormone (FSH)-induced production of gonadotrophin surge-inhibiting factor (GnSIF) on three phases of the pituitary responsiveness to gonadotrophin releasing hormone (GnRH): the unprimed, primed and desensitized phases. Rats were injected with FSH on two occasions during the oestrous cycle. Spontaneous luteinizing hormone (LH) surges were measured as well as GnRH-induced LH surges on the day of pro-oestrus during infusions with 100-4000 pmol GnRH/rat/10 h, in phenobarbital blocked rats. The spontaneous LH surges were attenuated or completely inhibited by the FSH treatment. FSH suppresses and prolongs the unprimed LH response and delays GnRH self-priming, especially during infusions with low concentrations of GnRH. This treatment does not affect the total LH response (area under curve) to the highest concentrations of GnRH and after ovariectomy. On the other hand, this response is suppressed during infusions with the lower concentrations of GnRH. Hence, FSH, via GnSIF, delays maximal priming of the LH response to GnRH, whereas the suppression of LH release is a consequence of the GnRH-induced progressed state of desensitization. The inconsistent effects of FSH on the mid-cycle LH surges are explained as a result of the interaction between the relative strengths of GnRH and GnSIF.  相似文献   

4.
Paradoxical response of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and alpha-subunits (alpha-SU) to thyrotropin-releasing hormone (TRH) have previously been reported in individuals with clinically nonfunctioning pituitary tumors (NFT). In the present study, we assessed the in vivo responses of LH, FSH, alpha-SU to TRH in 34 patients with NFT and 29 patients with agromegaly. Twenty-three clinically NFT were postoperatively analyzed by immunocytochemistry and 21 stained positive for beta-FSH and/or beta-LH. Two patients with NFT had elevated basal circulating levels of FSH (41.5 IU/L) and thus were characterized as FSH-secreting adenomas. TRH in these patients increased LH from basal 1.6 IU/L to 32.6 IU/L. In other patients with NFT, circulating levels of glycoprotein peptides were not elevated. TRH induced significant rise of LH in 8 (23.5%), FSH in 5 (14.7%), and alpha-SU in 10 (29.4%) patients with NFT. Thus, a bolus dose of TRH elicited a notable increment in FSH, LH or alpha-SU in 23 of 34 patients with NFT. Among 29 patients with acromegaly, LH rose in 6 (20.7%), FSH in 5 (17.2%), and alpha-SU in 3 (10.3%) patients. In conclusion: (1) We confirm that most NFTs are capable of synthesizing gonadotropin hormones and subunits (beta-FSH, beta-LH). (2) Most patients in our study responded by either FSH, LH or alpha-SU secretion after TRH, independent of basal hormone levels. Furthermore, recent studies show that by measurement of TRH stimulated beta-FSH and beta-LH one might further improve the diagnostic tools. (3) Gonadotropin response and possibly alpha-SU to TRH are also found in some patients with acromegaly. This could be a marker of a plurihormonal pituitary tumor.  相似文献   

5.
Clomiphene citrate was administered to 17 patients with either secondary amenorrhea or oligomenorrhea to study its effect on hypothalamic-pituitary response. Measurement of pulsatile gonadotropin output was accomplished utilizing samples collected every 20 minutes for 6 to 8 hours before and after clomiphene administration. Response to 100 mug synthetic luteinizing hormone releasing hormone (LRH) was measured at the end of the sampling period. Patients with polycystic ovarian disease who ovulated showed increased baseline FSH and LH, decreased peak LH, and a decrease in the percentage increase over baseline for both LH and FSH. On patient wil clinical anorexia nervosa responded to clomiphene as an estrogen, with lowered baseline LH and FSH values. Patients with resolving anorexia responded to clomiphene as an antiestrogen, with increased baseline gonadotropins, and decreased gonadotropin peak values. A patient with a surgically treated chromophobe adenoma showed no change in parameters measured before and after clomiphene administration. Baseline and pulsatile LH output appear to reflect the tonic output of gonadotropin as affected by estrogen acting in a negative feedback system, and the peak response to LRH administration, the response to the positive feedback of estrogen. Thus, LRH stimulation in clomipheneresistent patients may be of value in diagnosing the site and degree of the defect and aid in improving therapy.  相似文献   

6.
Accumulating evidence suggests that hypothalamic luteinizing hormone-releasing hormone (LHRH) and thyrotropin-releasing hormone (TRH) are two hypophysiotropic factors which modulate the immune response. The aim of the present study was to determine the in vivo effects of an intravenous bolus of LHRH and TRH on plasma interferon (IFN)-gamma production in five normoprolactinemic women with irregular menstrual cycles. We also determined prolactin (PRL), thyrotropin (TSH), follicle stimulating hormone (FSH), and luteinizing hormone (LH) levels before and after intravenous administration of LHRH and TRH. The results demonstrate that intravenous bolus of LHRH/TRH increases plasma IFN-gamma levels, with the maximum response 45 min after in vivo administration of hypothalamic peptides and after peak levels of adenohypophyseal hormones (PRL: 15 min; TSH: 30 min; FSH: 30 min; LH: 30 min). In order to investigate a possible direct action of hypothalamic hormones on immune cells, we also evaluated, in the same subjects, the influence of LHRH and TRH on IFN-gamma production by human peripheral blood mononuclear cells (PBMCs), collected before the intravenous administration of the peptides and stimulated in vitro with bacterial superantigen staphylococcal enterotoxin A (SEA) and concanavalin A (Con A). LHRH and TRH, separately and together, significantly enhanced in vitro IFN-gamma production by SEA- and ConA-activated PBMCs. The present results suggest that hypothalamic peptides (LHRH and TRH) directly, and/or indirectly pituitary hormones (PRL, TSH, FSH, and LH) or IL-2, have stimulatory effect on IFN-gamma producing cells and are further evidence of interactions between the neuroendocrine and immune systems.  相似文献   

7.
Temporal changes in plasma LH and FSH concentrations were monitored during the afternoon of proestrus in controls and in rats in which the spontaneous LH/FSH surges were blocked with Nembutal. These values were compared with those obtained following electrochemical stimulation (ECS) of either the medial preoptic area (MPOA) or the dorsal anterior hypothalamic area (DAHA) in similar Nembutal-blocked animals. Whereas MPOA-ECS (60 muA/60 sec) elicited a release of both FSH and LH, similar unilateral stimulation of the DAHA resulted in a pronounced increase in plasma FSH and only a slight elevation in plasma LH. Increasing the amount of DAHA tissue stimulated (100 muA/60 sec) caused a significantly greater release of FSH but not LH. Bilateral DAHA-ECS (60 muA/60 sec) failed to produce a greater release of FSH than that observed after unilateral 100 muA/60 sec ECS but resulted in increased concentrations of LH in plasma. Surgical separation of the MPOA from the DAHA, leaving the preopticotuberal fibers intact, did not alter the spontaneous temporal patterns of discharge of FSH or LH 19-21 days post-operatively, although peak LH concentrations were reduced. Further, unilateral ECS (60 muA/60 sec) of the MPOA in such preparations elicited a release of FSH and LH similar to that observed in intact MPOA-ECS rats. In contrast, unilateral DAHA ECS (60 muA/60 sec) in rats with transected hypothalami, caused no release of LH and an attenuated FSH discharge when compared with intact DAHA-ECS rats (peak valued 189 +/- 8 ng/ml vs 274 +/- 11 ng/ml). These studies suggest the existence of specific cell bodies in the DAHA which can cause selective release of FSH when activated. Coexisting with this system is that level of control which is believed to be responsible for the cyclic discharge of both FSH and LH of which the MPOA is a component part.  相似文献   

8.
Daily blood samples were obtained from 5 postmenopausal patients for 21 days and analyzed for plasma follicle stimulating hormone (FSH), luteinizing hormone (LH), estrone, estradiol, progesterone, and serum T4. On days 8 through 14, oral thyrotropin-releasing hormone (TRH) was administered, 50 mg, 4 times a day. All patients showed asignificant T4 response. There was, however, no significant change in the plasma FSH, LH, estrone, estradiol, or progesterone. We conclude that oral administration ofTRH has no influence on the elevated circulating concentration of FSH and LH seen in the postmenopausal female.  相似文献   

9.
Lordosis was elecited in 49% of 87 hormonally untreated, hypophysectomized-ovariectomized (hypox-ovx) female rats in response to palpation of the flanks and perineum (vaginal stimulation was not applied). By contrast, only 12% of 113 hormonally untreated ovariectomized (ovx) rats showed lordosis in response to such stimulation. Subsequently, hypox-ovx and ovx-only rats were given daily injections of 1 mug/kg estradiol benzoate (EB) and tested for sexual receptivity with males. Teh estrogen-treated hypox-ovx females became sexually receptive significantly earlier, and exhibited higher lordosis quotients and more soliciting behavior, than the estrogen-treated ovx-only rats. The increased sexual responsiveness in the hypox-ovx rats could be due to increased LRH activity. To test this, we treated hypox-ovx rats with dihydrotestosterone propionate (DHT-P), which suppresses plasma LH levels but is relatively ineffective in inducing sexual receptivity, and found a significant depression of lordosis responsiveness. These experiments suggest that hypox-ovx females show a heightened responsiveness to hormonal and/or sensory factors that induce a lordosis response, possibly because of increased LRH activity.  相似文献   

10.
This study compared the changes in pituitary and serum levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) at various times following ovariectomy (OVX) between young cyclic and middle-aged persistent-estrous (PE) rats and related these to the relative gene expression of the pituitary gonadotropin subunits. In intact animals, both pituitary and serum levels of LH were similar between these two age groups, while the LH beta mRNA expression was significantly (p < 0.05) greater in young rats. Following OVX in young rats, the serum LH levels markedly increased (p < 0.05) beginning on day 7 and reaching a maximum fourfold increase by day 9. In contrast, the post-OVX increases in serum LH in middle-aged females were significantly delayed. OVX significantly (p < 0.05) increased pituitary LH contents of young rats by day 5, but had no effect on LH contents in middle-aged females until day 30 post-OVX. These changes were associated with increases in LH beta mRNA expression in both young and middle-aged females, but the levels were significantly (p < 0.05) lower in middle-aged females. Both pituitary and serum levels of FSH were significantly (p < 0.05) higher in middle-aged PE than in young rats prior to OVX, while the FSH beta mRNA expression was similar in both age groups. Following OVX in young rats, serum FSH levels rapidly increased (p < 0.05) on day 3 and attained tenfold higher values by day 30.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

11.
OBJECTIVE: To investigate the relationship between renin-angiotensin system (RAS) and polycystic ovarian syndrome (PCOS) METHODS: A pituitary-stimulating test with luteinizing hormone releasing hormone (LRH, 100 micrograms) was performed in two PCOS groups with similar mean testosteron (T) levels of luteinizing hormone/follicular stimulating hormone (LH/FSH) (LH/FSH > or = 3, group 1, n = 15; LH/FSH < 3, group 2, n = 15) and the controls (n = 20) of matched body mass index with group 1. The basal level and LRH-evoked responses of LH, plasma renin activity (PRA), angiotensin II (AT II ) and aldosterone (ALD) were measured by RIA with commercially available kits. In the basal state, a positive correlation was found between T and AT II levels (r = 0. 49, P < 0.05) in all PCOS subjects. After LRH administration, susceptible individuals, especially of group 1 had exaggerated responses of LH, PRA, AT II and ALD as compared with the controls, and a positive correlation was also found between peak levels of LH and AT II (r = 0.54, P < 0.01). CONCLUSIONS: There is enhanced RAS function in PCOS especially in group 1. This may contribute to the excess androgen production and high incidence of ovarian hyperstimulation syndrome in this disorder.  相似文献   

12.
Studies have emphasized the role of the medial preoptic area (MPOA) as an important site for the regulation of male sexual behavior. Indeed, ablations of the MPOA impair sexual behavior, whereas stimulation of the MPOA enhances behavior. Furthermore, neural activity in the MPOA increases with mating. The current study tested the hypothesis that activation of N-methyl-D-aspartate (NMDA) receptors occurs in MPOA neurons and is essential for the expression of male sexual behavior in rats. Results indicate that nearly all MPOA neurons that expressed Fos following mating also contained the NR1 subunit of NMDA receptors. Furthermore, mating increased phosphorylation, thus activation, of NR1 in the MPOA. Additionally, blocking NMDA receptors significantly decreased mating-induced Fos expression and mating-induced phosphorylation of NMDA receptors and impaired male sexual behavior. These results provide evidence that mating activates NMDA receptors in the MPOA and that this activation is important for the expression of male sexual behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

13.
The lateral connections of the medial preoptic area (MPOA) are essential for maternal behavior in rats. The purpose of this study was to more exactly specify the nature of this pathway. Exp 1 found that knife cuts that severed the dorsolateral connections of the MPOA were as effective as complete cuts in disrupting maternal behavior, whereas knife cuts that severed the ventrolateral MPOA connections were ineffective. These results suggest that MPOA efferents and afferents critical for maternal behavior leave or enter the MPOA dorsolaterally. Exp 2 located possible sources of critical afferent input. Lactating rats received MPOA lateral cuts with a horseradish peroxidase (HRP)-coated wire knife. Full lateral cuts and dorsolateral cuts disrupted maternal behavior and labeled more cells with HRP in the nucleus of the solitary tract and the locus coeruleus than did ventrolateral cuts, which did not disrupt maternal behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

14.
In this study the levels of mRNA for the pituitary gonadotropin hormone subunits luteinizing hormone beta (LHbeta), follicle stimulating hormone beta (FSHbeta) and the common alpha-subunit were assessed during the acute feedback stages of estradiol benzoate (EB) action in ovariectomized (OVX) ewes with and without hypothalamo-pituitary disconnection (HPD). In OVX/HPD ewes maintained on hourly pulses of 250 micrograms of gonadotropin-releasing hormone (GnRH) a single i.m. injection of EB in oil caused a biphasic (decrease and then increase) change in plasma LH levels and a monophasic decrease in FSH levels. There was a decrease in pituitary alpha-subunit and FSHbeta mRNA levels during the acute negative (8 h post EB) and through the positive feedback (20 h post EB) stages of the response. No significant change was seen in LHbeta mRNA levels following treatment with EB. In hypothalamic-pituitary intact OVX ewes the same EB treatment as above caused a biphasic change in LH secretion with the positive feedback component being much greater than in GnRH-pulsed OVX-HPD ewes. The levels of mRNA for all three gonadotropin subunits were reduced by 8 h after EB injections and remained low throughout the positive feedback period. These data suggest that the LH surge in this experimental model does not require an increase in LHB mRNA levels. Furthermore, the fall in LHbeta subunit mRNA seen after estrogen injection of OVX ewes is most likely due to an effect of estrogen to decrease GnRH secretion, since pulsatile GnRH replacement prevents this effect. These data also show that estrogen feedback can effect rapid alterations in pituitary gonadotropin subunit mRNA levels. Short-term changes in FSHbeta mRNA are reflected in changes in FSH secretion; the same is not true for LH.  相似文献   

15.
The present study examined whether blockade of kappa-opioid receptors in the medial preoptic area (MPOA) prior to the critical period on the afternoon of proestrus could prematurely evoke an ovulatory luteinizing hormone (LH) surge, and if so, whether norepinephrine (NE) is involved in mediating this response. In the first experiment, push-pull perfusion of the MPOA with nor-binaltorphimine (nor-BNI), a specific kappa-opioid receptor antagonist, was done in rats between 10.30 and 13.50 h on proestrus. To determine whether any resulting ovulation was due to a nor-BNI-induced increase in LH release, rats were injected with pentobarbital at 13.55 h to block the afternoon LH surge. In 7 of 10 rats, nor-BNI in the MPOA produced a large increase in LH release beginning between 12.30 and 13.30 h, and 5 of 7 ovulated. During MPOA perfusion with cerebrospinal fluid in our normal colony between 14.00 and 17.00 h, surges of LH release began in the majority of rats between 15.30 and 16.30 h. Thus blockade of MPOA kappa-opioid receptors advanced the LH surge by 3 h. The next experiment examined the effect of NE synthesis inhibition with bis(4-methyl-1-homopiperazinylthiocarbonyl) disulfide (FLA-63), or alpha-adrenergic receptor blockade with phenoxybenzamine (PBZ), on the nor-BNI-induced LH response. In 5 of 6 vehicle-treated rats, blockade of MPOA kappa-opioid receptors elicited a large increase in LH release and all 5 ovulated. In contrast, only 3 of 8 rats pretreated with FLA-63 had a large increase in LH release and ovulated, and PBZ prevented the nor-BNI-induced LH increase and ovulation in 4 of 4 rats. PBZ also prevented the afternoon LH surge and ovulation in 4 of 4 rats in our normal colony. Finally, HPLC measurement of NE levels in MPOA push-pull perfusate indicated no increase in NE release during the nor-BNI-induced or normal afternoon LH surges. These results indicate that antagonism of kappa-opioid receptors in the MPOA can prematurely evoke an ovulatory LH surge prior to the critical period on the afternoon of proestrus. Furthermore, the nor-BNI-induced as well as the normal afternoon LH surges are dependent on the proper functioning of central noradrenergic neurons, but do not involve increased NE release within the MPOA.  相似文献   

16.
In Exp I, with 21 female Charles River CD rats, bilateral electrolytic lesions of the ventral tegmental area (VTA) severely disrupted maternal behavior. In Exp II, with 56 Ss, lactating Ss that received a unilateral knife cut severing the lateral connections of the medial preoptic area (MPOA) paired with a contralateral lesion of the VTA showed more severe maternal behavior deficits than Ss that received (a) a cut severing the lateral connections of the MPOA paired with an ipsilateral VTA lesion; (b) a cut severing the lateral connections of the MPOA paired with a contralateral lesion of the medial hypothalamus posterior to the MPOA; or (c) a cut severing the lateral connections of the lateral preoptic area paired with a contralateral VTA lesion. The oral components of maternal behavior (retrieving and nest building) were particularly affected as a result of bilateral damage to the system extending from the preoptic area to the VTA. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

17.
The behavioral effects of alpha-MSH, MCH, and alpha-MSH + MCH were investigated in the ventromedial nucleus (VMN) and medial preoptic area (MPOA) (bilateral, 100 ng in 0.5 microliter). Infusion of alpha-MSH into the VMN increased aggressive behavior; in the MPOA it reduced exploration and increased anxiety. In both areas it stimulated sexual behavior. MCH also stimulated sexual behavior in the MPOA and VMN and had an anxiogenic effect in the MPOA. The effect of alpha-MSH on aggression and exploration was antagonized by MCH. When given together, the two peptides were mutually antagonistic on anxiety. This study indicates that MCH has central nervous system effects and may be a partial alpha-MSH agonist.  相似文献   

18.
Oxytocin binding (Bmax) was found to be higher in the ventral tegmental area (VTA) and the medial preoptic area (MPOA) at midparturition compared with Pregnancy Days 15–27 or Postpartum Days 5–7 in rat dams. Pup retrieval and assuming a nursing posture over pups were blocked in parturient dams by infusions of an oxytocin antagonist into the VTA or MPOA and by infusions of a vasopressin (V?) antagonist into the MPOA. These results implicate oxytocin in the VTA and MPOA and vasopressin in the MPOA, as well as a parturition-associated rise in oxytocin binding in these sites in the postpartum activation of maternal behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

19.
Three experiments examined whether the medial preoptic area (MPOA) is involved in the onset of maternal behavior in the rat. Exp I, with 54 female Charles River CD rats, investigated whether estradiol benzoate (EB) acts on the MPOA to facilitate the onset of maternal behavior in 16-day pregnant, hysterectomized, and ovariectomized Ss. When given EB implants in the MPOA, these Ss had significantly shorter latencies for the onset of maternal behavior than those implanted with cholesterol in the MPOA or with EB in the ventromedial hypothalamus, in mammillary bodies, or under the skin. Exp II, with 62 Ss, showed that estrogen-induced prolactin release was not involved in this facilitation. Exp III, with 35 Ss, showed that MPOA lesions disrupted the onset of maternal behavior induced by pup stimulation in virgin females. (11/2 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

20.
Determined whether infusions of naloxone into specific brain sites can block sexual reinforcement as evaluated with the conditioned place preference procedure. Methylnaloxonium (5 μg/cannula) was infused bilaterally either into the medial preoptic area (MPOA) or into the nucleus accumbens (NAC) of sexually experienced male rats. The MPOA was chosen because it is important for sexual behavior, and several opioid peptides have been shown to modify sexual behavior when infused there. The NAC appears to be a critical structure for drug-induced reward. Methylnaloxonium blocked place preference produced by ejaculation after infusion into the MPOA without affecting sexual behavior. Infusion of the antagonist into the NAC did not reduce the reinforcing properties of ejaculation. Data suggest that the MPOA may be a site where sexual reward is produced. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号