共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
Luteinizing Hormone (LH) from goat pituitary glands has been purified and characterized with respect to its size and subunit nature. The purification at each step was monitored by protein estimation, SDS-PAGE, and direct binding ELISA. The final product was found to be over 90 fold purified as compared to the starting pituitary extract, and the yield of the final purified LH was found to be 65.3 mg/kilogram of wet pituitary glands. Fractionation of the cLH into different charge isoforms by SP-Sephadex ion exchanger has been observed. Chromatography on immobilized Con A lectin resulted in fractionation of the purified cLH into unbound (2%), loosely bound (85%), and firmly bound (13%) fractions indicating oligosaccharide heterogeneity. The purified hormone was capable of stimulating weight increase in the seminal vesicles in immature male rats, with a biopotency equivalent to the 2200 I.U. of hCG per mg of purified cLH. The FSH content of the purified cLH was found to be less than 0.0165% as indicated by in vivo Steelman-Pohley assay. 相似文献
3.
Fifteen Suffolk ewes were used in three experiments to compare plasma follicle stimulating hormone (FSH) and luteinizing hormone (LH) patterns during the estrous cycle and to determine whether FSH levels undergo changes in pulse frequency. Luteinizing hormone changed inversely with progesterone levels whereas FSH and progesterone concentrations revealed no obvious relationship. Unlike LH, FSH levels did not pulsate during the follicular phase. Higher FSH levels were detected on days 1, 6 and 12 and lower levels on days 0, 4 and 16. Coincident preovulatory LH and FSH surges were observed and this was the only time FSH and LH levels appeared to be jointly controlled. 相似文献
4.
T T Stumpf M L Day M W Wolfe A C Clutter J A Stotts P L Wolfe R J Kittok J E Kinder 《Biology of reproduction》1989,41(1):91-97
Mean concentrations of luteinizing hormone (LH) increase during the follicular phase of the estrous cycle in cows. The working hypotheses in the present study were (1) that increasing concentrations of 17 beta-estradiol (E2) during the follicular phase of the estrous cycle cause an increase in mean concentration of LH by increasing amplitude of pulses of LH, and (2) that increasing E2 concentrations during this stage of the estrous cycle decrease frequency of pulses of LH in bovine females. Day of estrus was synchronized in seventeen mature cows. Treatments were initiated on Day 16 of the experimental estrous cycle (Day 0 = estrus). At Hour 0 (on Day 16), 4 cows were lutectomized. Lutectomy of these cows (EE; n = 4) allowed for endogenous secretion of E2. The remaining cows were ovariectomized at Hour 0 and were assigned to one of three E2 treatments: luteal phase E2 (LE, n = 5), increasing then decreasing E2 (DE, n = 5), and no E2 (NE, n = 3). Cows in the group that received LE were administered one E2 implant at Hour 0, which provided low circulating concentrations of E2 similar to those observed during the luteal phase of the estrous cycle. Cows in the group that received DE were administered one E2 implant at Hour 0, and additional implants were administered at 8-h intervals through Hour 40; then, two implants were removed at Hours 48 and 56, and one implant was removed at Hour 64.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
5.
The Cape ground squirrel Xerus inauris is unusual among social mammals as it exhibits a low reproductive skew, being a facultative plural breeder with not all females breeding within a group. We investigated pituitary function to assess whether there was reproductive inhibition at the level of the pituitary and potentially the hypothalamus in breeding and non-breeding female Cape ground squirrels. We did so during the summer and winter periods by measuring luteinizing hormone (LH) responses to single doses of 2 g exogenous gonadotropin-releasing hormone (GnRH) and physiological saline administered to 42 females from 11 colonies. Basal LH concentrations of females increased in response to the GnRH challenge. Basal plasma LH concentrations were greater during winter, when most oestrus events are observed. However, we found no differences in plasma LH concentrations between breeding and non-breeding females. We showed that the anterior pituitary of non-breeding female ground squirrels is no less sensitive to exogenously administered GnRH than that of breeding females. We therefore concluded that the pituitary is no more active in breeding than non-breeding females. The lack of differentiation in response to GnRH suggests that either non-breeding females have ovaries that are less sensitive to LH or that they refrain from sexual activity with males through an alternative mechanism of self-restraint. 相似文献
6.
The changes in serum gonadotrophins in male hamsters following one injection of 15 μg luteinizing hormone releasing hormone (LHRH) (Group A) were compared with those following the last injection of LHRH in animals receiving an injection approximately every 12 hr for 4 days (Group B) or 12 days (Group C). Peak follicle stimulating hormone (FSH) levels (ng/ml) were 1776±218 (Group A), 2904±346 (Group B), and 4336±449 (Group C). Peak luteinizing hormone (LH) values (ng/ml) were 1352±80 (Group A), 410±12 (Group B), and 498±53 (Group C). Serum FSH:LH ratios, calculated from the concentrations measured 16 hr after the last LHRH injections, were higher in Groups B and C than in Group A. Similar injections of LHRH (100 ng or 15 μg/injection) for 6 days elevated the serum FSH:LH ratio in intact males. Five such LHRH injections (100 ng/injection) blunted the rise in serum LH in orchidectomized hamsters. Direct effects of LHRH on gonadotrophin secretory dynamics or altered brain-pituitary-testicular interactions may alter the ratio of FSH to LH in the hamster. 相似文献
7.
8.
Saint-Dizier M Malandain E Thoumire S Remy B Chastant-Maillard S 《Molecular reproduction and development》2007,74(8):989-996
In order to better understand the pituitary regulation of follicular growth in the domestic cat, follicle stimulating hormone (FSH) and luteinizing hormone (LH) receptors (R) were localized and quantified in relation to follicle diameter and atresia using in situ ligand binding on ovarian sections. Expression of FSHR was homogeneous and restricted to follicle granulosa cells from the early antral stage onwards, whereas expression of LHR was heterogeneous on theca cells of all follicles from the early antral stage onward, and homogeneous on granulosa cells of healthy follicles larger than 800 microm in diameter and in corpora lutea. LHR were also widely expressed as heterogeneous aggregates in the ovarian interstitial tissue. Atretic follicles exhibited significantly reduced levels of both FSHR and LHR on granulosa cells, compared with healthy follicles whatever the follicular diameter, whereas levels of LHR on theca cells were lower only for atretic follicles larger than 1,600 microm in diameter. In healthy follicles, levels of FSHR and LHR in all follicular compartments increased significantly with diameter. Although generally comparable to that observed in other mammals, the expression pattern of gonadotropin receptors in the cat ovary is characterized by an early acquisition of LHR on granulosa cells of growing follicles and islets of LH binding sites in the ovarian interstitial tissue. 相似文献
9.
R P Millar C Aehnelt G Rossier 《Biochemical and biophysical research communications》1977,74(2):720-731
Separation of extracts of sheep hypothalami on Sephadex G-25 gave three peaks exhibiting luteinizing hormone releasing hormone immunoreactivity. One peak corresponded in elution volume with luteinizing hormone releasing hormone but the others (I and II) eluted earlier, indicating that they are of higher molecular weight. Elution volumes were unaffected by 8 M urea treatment. Incubation of I and II with hypothalamic peptidases produced a small quantity of immunoreactive material eluting in the luteinizing hormone releasing hormone region. Digestion of I with trypsin resulted in a marked increase in total immunoreactivity and the production of material with the same elution volume as II. Tryptic digestion of II gave rise to a small quantity of immunoreactive peptide eluting in the luteinizing hormone releasing hormone region. The amount of I and II relative to luteinizing hormone releasing hormone was lower in the median eminence than in the supra optic chiasmatic and basal hypothalamic regions. 相似文献
10.
Perera-Marín G Murcia C Rojas S Hernández-Cerón J González-Padilla E 《Animal reproduction science》2005,86(1-2):53-69
The pattern of distribution of circulating luteinizing hormone (LH) isoforms in cattle during estrus and the luteal phase was investigated. In each stage, the stage of the estrous cycle was synchronized in seven Holstein heifers with a prostaglandin analogue. After estrus was detected, blood samples were taken at 2-h intervals for 24h. In the luteal phase, animals received 250 microg i.v. of GnRH and blood samples were collected every 15 min for 5h. LH concentration in the samples was determined. Samples with the greatest LH concentration in estrus (pre-ovulatory peak) and those collected 60 min after GnRH administration (luteal phase) were analyzed by chromatofocusing, eluted with a pH gradient from 10.5 to 3.5. Eluted LH was grouped into basic (pH > or = 7.5), neutral (pH 7.4-6.5) and acidic isoforms (pH < or = 6.4) as well as by pH unit. In both phases, basic forms were the most abundant, and these were greater (P < 0.05) during the luteal phase (78.4 +/- 4.2%) as compared with during estrus (57.1 +/- 6.2%); the proportion of neutral and acidic isoforms in estrus (13.7 +/- 2.6%; 28.5 +/- 2.8%) was greater (P < 0.05) as compared with the luteal phase (3.0 +/- 0.7; 18.7 +/- 3.4). These results indicate that the relative proportion of LH isoforms secreted by the adenohypophysis differ by stage of estrous cycle. The addition of excess of NaCl to the column modifies the antigen-antibody binding in the RIA, and the proteins eluted are erroneously quantified as LH; this is an artifact of the technique. 相似文献
11.
12.
Sequential bleeding and push-pull perfusion of the hypothalamus were used to characterize luteinizing hormone (LH) and LH-releasing hormone (LHRH) release in ovariectomized (OVX) ewes after injection of corn oil or estradiol benzoate (EB). Push-pull cannulae were surgically implanted into the stalk median eminences of 24 OVX ewes. Seven to 14 days later each of 20 animals was given an i.m. injection of 50 micrograms EB. Blood samples and push-pull perfusate were collected at 10-min intervals for 6-12 h beginning 12-15 h after EB injection. Four OVX ewes were given i.m. injections of corn oil 7 days after implantation of push-pull cannulae. Blood samples and push-pull perfusate were collected at 10-min intervals for 4 h between 18 and 22 h after injection of corn oil. Luteinizing hormone remained below 2 ng/ml throughout most of the sampling periods in 9 of 20 EB-treated ewes. In 5 of these 9 LHRH also was undetectable, whereas in 4 LHRH was detectable (1.84 +/- 0.29 pg/10 min), but did not increase with time. Preovulatory-like surges of LH occurred in 11 EB-treated ewes, but LHRH was undetectable in 5. In 4 of 6 ewes showing LH surges and detectable LHRH, sampling occurred during the onset of the LH surge.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
13.
缓释型促性腺激素释放激素与生长激素治疗儿童中枢性性早熟的疗效观察 总被引:2,自引:0,他引:2
目的用生长激素与促性腺激素释放激素类似物(Gonadotropin-releasing hormone analogues,GHA)联合治疗中枢性性早熟女性患儿对其最终成人身高的影响.方法生长激素(GH)与促性腺激素释放激素类似物(GHA)联合治疗4例中枢性性早熟女性患儿半年,对比治疗前后患儿的第二性征,骨龄发育,性激素及最终成人身高的变化.结果第二性征的发育停止,骨龄发育被控制,实际生活年龄与骨年龄的比值提高(平均0.79→0.84);血LH对促性腺激素释放激素的反应及血浆雌激素水平平均已降至青春期前,分别为(平均25.79±10.60mlu/ml→1.13±0.21mlu/ml)及(平均64.87±27.51pg/ml→3.03±1.87pg/ml);预测最终成人身高增加(平均149.60±4.31cm→156.75±3.84cm)差异具有显著性(P<0.05).结论生长激素与GHA联合治疗中枢性性早熟患儿,不仅能抑制第二性征发育,而且能有效改善最终成人身高,无任何毒付作用. 相似文献
14.
Adjacent tissue sections through the rat median eminence were examined for the distribution of gonadotropin-releasing hormone (GnRH) and catecholamines (CA). A simultaneous visualization technique was employed for this correlative neuroanatomical analysis. At rostral and mid-central levels of the median eminence the majority of GnRH terminals do not appear in coexistence with CA terminals; the latter were confined to the outer-most 10 μm of the median eminence while the densest concentration of GnRH terminals was located internal to this layer. However, individual GnRH fibers appeared to penetrate the outer CA zone wherein they were found in juxtaposition to portal capillaries. At caudal levels of the median eminence, there was an extensive overlap of CA and GnRH varicosities adjacent to the tubero-infundibular sulcus. In addition, numerous GnRH terminals were seen adjacent to portal vessels. The differences in the positions of CA and GnRH terminals between rostral and caudal median eminence may provide a morphological basis for the hypothesis of separate regulatory mechanisms for CA upon GnRH secretion at these two levels of the median eminence. 相似文献
15.
Summary The hypothalamic hormones arginine-vasopressin (AVP), oxytocin (OXT), somatostatin (SOM), and luteinizing hormone-releasing hormone (LHRH) were localized in the rat neurohypophysis by the use of semithin serial sections and the unlabeled antibody enzyme method. Clusters of AVP fibres are present within the central region of the neural lobe, clusters of OXT fibres mainly in the peripheral part. The AVP fibres enter bilaterally into the neural lobe.The results call into question previous reports on the presence of AVP on receptors in the pars intermedia cells, since incubation with anti-AVP resulted in similar staining in the pars intermedia of the Wistar and homozygous Brattleboro rat, a mutant strain deficient in AVP. The same intermediate lobe cells are stained after incubation of serial sections with anti-AVP and anti--melanocyte-stimulating hormone (-MSH). This staining of anti-AVP could be removed by solid phase absorption to -MSH and is thus most probably due to cross reaction with -MSH. SOM fibres appear to be present in the peripheral parts of the proximal neurohypophysial stalk and mainly lateral in its more distal parts. In the neural lobe they rapidly decrease in number, although some fibres continue into the distal part of the neural lobe, running bilaterally and situated adjacent to the pars intermedia. The SOM staining within magnocellular elements, which has been reported in the literature, can most probably be explained by cross reaction of anti-SOM with neurophysins. LHRH fibres are very scarce in the neurohypophysial stalk and absent in the neural lobe.Supported by the Foundation for Medical Research FUNGOThe authors wish to thank Drs. J. De Mey (Beerse, Belgium), A. Arimura (New Orleans, U.S.A.), M.P. Dubois (Nouzilly, France), B.L. Baker (Ann Arbor, U.S.A.) and A.G.E. Pearse (London, U.K.) for their gifts of anti-somatostatin serum, Dr. B. Kerdelhué (Gif-sur-Yvette, France) for anti-LHRH serum, and Dr. F. Vandesande (Ghent, Belgium) for anti-neurophysin I and II serum and bovine neurophysin I and II. Dr. J.G. Streefkerk (Free University, Amsterdam) is acknowledged for critical comments and Mr. A.T. Potjer and Miss J. van der Velden for their skilled assistance 相似文献
16.
U S Seal E D Plotka J D Smith F H Wright N J Reindl R S Taylor M F Seal 《Biology of reproduction》1985,32(2):361-368
Seasonal analysis of 1239 captive births of Siberian tigers (Panthera tigris altaica) indicated a peak in April to June (P less than 0.001). Studies on seven animals in Minnesota indicated that behavioral heat cycles and ovarian follicular phase cycles began in late January and ceased in early June. Behavioral observation of 12 heat cycles in four tigers yielded an estrous length of 5.3 +/- 0.2 days and an interestrous interval of 25.0 +/- 1.3 days. Hormone assays on weekly blood samples (N = 180) from three female tigers indicated 16 cycles in two breeding seasons. Peak estradiol-17 beta levels were 46.7 +/- 6.0 pg/ml (N = 17) and interestrous concentrations were 8.7 +/- 0.66 pg/ml (N = 28) during the breeding season. Anestrous estradiol levels were 4.2 +/- 0.5 pg/ml (N = 70). The interestrous interval between estradiol peaks was 24.9 +/- 1.3 days (N = 9) with two outliers of 42 days. Serum progesterone concentrations from February to June were 1.2 +/- 0.15 ng/ml (N = 32), providing no evidence for ovulation or corpus luteum formation. Luteinizing hormone (LH) levels were 0.56 +/- 0.04 ng/ml (N = 180). Serum testosterone (r=0.71, P less than 0.001) and androstenedione levels (r=0.75, P less than 0.001) were correlated with estradiol during the breeding season. The duration of anestrus was 8 mo in two of these tigers. The interval was shortened in one tiger by exposure to a 16L:8D photoperiod. The Siberian tiger appears to be a polyestrous seasonal breeder and an induced ovulator whose breeding season may be synchronized by photoperiod. 相似文献
17.
Three experiments were conducted on anestrous ewes of Suffolk, Dorset, and Katahdin breeding to examine the potential value of GnRH to improve ovulation and pregnancy in response to introduction of rams. In Experiment 1, treatment with GnRH 2 d after treatment with progesterone (P4; 25 mg i.m.) at introduction of rams was compared to treatment with P4 alone at the time of introduction of rams. Treatment with GnRH did not increase percentages of ewes with a corpus luteum (CL) 14 d after introduction of rams, pregnant 32 d after treatment with PGF2α 14 d after introduction of rams, or percent of treated ewes lambing to all services. In Experiment 2, treatments with GnRH on day 2, 7, or both after introduction of rams were compared. Treatments did not differ in mean estrous response, percentages of ewes with a detectable CL or number of CL present on day 11, or mean pregnancy and lambing rates. Therefore, neither one nor two injections of GnRH at these times appeared to be effective to induce anestrous ewes to breed. In Experiment 3, treatments compared included GnRH 4 d before introduction of rams, GnRH 4 d before and 1 d after introduction of rams, ram introduction alone, and treatment with P4 (25 mg i.m.) at the time of introduction of rams. Percentages of ewes with concentrations of P4 greater than 1 ng/mL (indicating formation of CL had occurred) 7 d after ram introduction tended to be greater (P < 0.07) in ewes treated with GnRH or P4 than in control ewes treated with ram introduction alone. However, there was no difference in P4 concentrations between groups by day 11 or 12 after introduction of rams. Estrous response rates and percentages of ewes pregnant 95 d after PGF2α was administered (on day 12 after introduction of rams) tended to be greater (P = 0.08 and 0.06, respectively) in ewes treated with GnRH or P4 than in ewes exposed to rams only. There was no difference in response variables between ewes treated with GnRH 4 d before introduction of rams and ewes treated with GnRH 4 d before and 1 d after introduction of rams. In conclusion, treatment with GnRH 4 d before ram introduction showed promise as an alternative to treatment with P4 to improve the ovulatory response and reproductive performance of ewes introduced to rams during seasonal anestrus. 相似文献
18.
Juvenile hormone (JH I) stimulates specific morphological and biochemical changes in the follicular epithelium surrounding the terminal oöcytes in Leucophaea maderae. These include extracellular and intracellular structural changes, increased rates of follicle cell DNA synthesis, and elevated follicle cell DNA concentrations.Using females decapitated 24 hr after ecdysis, we have shown that JH I injections stimulate the following structural changes in the follicular epithelium: the appearance of channels between adjacent follicle cells and of spaces between the follicular epithelium and the maturing oöcyte; an increase in follicle cell size; the development of an extensive rough endoplasmic reticulum system; and an enlarged nucleus within each follicle cell. No increase in the number of follicle cells surrounding the developing terminal follicles is found in 7-day JH I-treated females, although the terminal follicles are almost twice as long as those in untreated females.In addition, we have demonstrated that JH stimulates the following biochemical events in the ovary: a 3.5 fold increase in thymidine incorporation into follicle cell DNA, with no subsequent transfer of such DNA to the developing oöcyte, and a 1.4 fold increase in ovarian DNA in 7-day JH-treated females. These data indicated that JH stimulates follicle cell DNA synthesis. The absence of any corresponding division of follicle cells suggests that JH I may induce polyploidy in follicle cells.Extended exposure of decapitated females to JH I does not result in complete ovarian maturation. Although fat bodies in the treated insects continue to display an increasing rate of vitellogenin synthesis, DNA synthesis in the terminal follicles declines rapidly after day 9, and the terminal follicles ultimately degenerate. 相似文献
19.
M Arslan S Mahmood S Khurshid S M Naqvi M A Afzal S M Baig 《Journal of medical primatology》1986,15(5):351-359
Basal serum levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) and the responsiveness of these hormones to a challenge dose of luteinizing hormone releasing hormone (LHRH), were determined in juvenile, pubertal, and adult rhesus monkeys. The monkey gonadotrophins were analyzed using RIA reagents supplied by the World Health Organization (WHO) Special Programme of Human Reproduction. The FSH levels which were near the assay sensitivity in immature monkeys (2.4 +/- 0.8 ng/ml) showed a discernible increase in pubertal animals (6.4 +/- 1.8 ng/ml). Compared to other two age groups, the serum FSH concentration was markedly higher (16.1 +/- 1.8 ng/ml) in adults. Serum LH levels were below the detectable limits of the assay in juvenile monkeys but rose to 16.2 +/- 3.1 ng/ml in pubertal animals. When compared to pubertal animals, a two-fold increase in LH levels paralleled changes in serum LH during the three developmental stages. Response of serum gonadotrophins and T levels to a challenge dose of LHRH (2.5 micrograms; i.v.) was variable in the different age groups. The present data suggest: an asynchronous rise of FSH and LH during the pubertal period and a temporal correlation between the testicular size and FSH concentrations; the challenge dose of LHRH, which induces a significant rise in serum LH and T levels, fails to elicit an FSH response in all the three age groups; and the pubertal as compared to adult monkeys release significantly larger quantities of LH in response to exogenous LHRH. 相似文献
20.
It is well established that the neuropeptide gonadotropin-releasing hormone (GnRH) regulates the secretion of pituitary gonadotropins. Evidence also suggests a neuromodulatory role for GnRH, yet its mechanism is unknown. It has recently been shown that in the medaka genome, the GnRH II and GnRH III genes reside adjoining the genes encoding protein tyrosine phosphatase alpha (PTPalpha) and PTP, respectively. Here we isolated and characterized PTPalpha and PTP in the medaka, and demonstrated using an in vitro medaka whole-brain culture system that GnRH downregulates the PTPalpha/PTP gene expression. This finding, together with the fact that PTPalpha/PTP regulate neuronal excitability through interacting with voltage-gated potassium channel, suggests that GnRH gene products would act as neuromodulators via downregulating their neighboring PTPalpha/PTP genes. 相似文献