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1.
S Mahabeer I Jialal R J Norman C Naidoo K Reddi S M Joubert 《Hormones et métabolisme》1989,21(9):502-506
Plasma glucose, immunoreactive insulin (IRI) and C-peptide responses during an oral glucose tolerance test (oGTT) were assessed in 11 non-obese patients with polycystic ovarian disease (PCOD) and 11 reference subjects matched for age, height and weight. Also, 6 patients with PCOD and 6 normal women were subjected to intravenous glucose tolerance testing (ivGTT) On oGTT, all subjects exhibited normal glucose tolerance; however, PCOD patients had significantly higher mean plasma glucose levels at 30, 60, 90 and 120 min and higher mean incremental glucose areas. In addition the patients with polycystic ovaries showed higher mean basal IRI and C-peptide levels, higher mean glucose stimulated IRI and C-peptide levels and higher mean incremental IRI and C-peptide values. The molar ratios of C-peptide/IRI were significantly lower in the PCOD group at all time intervals after glucose stimulation when compared to the normal women. During ivGTT, there were significantly higher mean glucose levels at 5, 40, 50 and 60 min in the PCOD group when compared to the reference group. The IRI response to intravenous glucose in the PCOD women was similar to the reference group. The findings on oGTT suggest that non-obese patients with PCOD have increased pancreatic IRI secretion as well as impaired hepatic extraction of the hormone. 相似文献
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Boars have high concentrations of plasma and testicular estrogens, but how this hormone is involved in feedback regulation of the gonadotropins and local regulation of testicular hormone production is unclear. The present study examined the effects of reducing endogenous estrogens by aromatase inhibition on concentrations of plasma LH and FSH and on testicular and plasma concentrations of testosterone (T) and immunoreactive inhibin (INH). Thirty-six littermate pairs of boars were used. One boar from each pair was assigned to the control group (vehicle); the other boar to the treatment group (aromatase enzyme inhibitor, Letrozole, 0.1 mg/kg body weight [BW]). Weekly oral treatment started at 1 wk of age and continued until castration at 2, 3, 4, 5, 6, 7, or 8 mo. Plasma concentrations of gonadotropins, INH, T, estradiol (E2), and estrogen conjugates (ECs) were determined. Testicular tissue was collected at castration for determination of INH and T and for confirmation of reduced aromatase activity. The acute effects of aromatase inhibition on gonadotropins were monitored in two adult boars treated once with Letrozole (0.1 mg/kg BW). Treatment with the aromatase inhibitor reduced testicular aromatase activity by 90% and decreased E2 and ECs without changing acute, long-term, or postcastration LH and FSH. Plasma T, testicular T, and circulating INH concentrations did not change. Testicular INH was elevated in treated boars compared with controls. In conclusion, estrogen does not appear to play a regulatory role on gonadotropin secretion in the developing boar. This is in direct contrast to findings in males of several other species. 相似文献
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L Pilotti P G Data G Di Tano 《Bollettino della Società italiana di biologia sperimentale》1984,60(10):1885-1890
In this study was investigated the diagnostic significance of double stimulation test with (that is of 25 micrograms rapid injection intravenously twice at an interval of 120 minutes and the misure of maximal net increment of serum LH after the first GnRH injection expressed as delta 1 and after the second injection, expressed as delta 2) to discriminate patients with idiopatic hirsutism. This test was effectuated on 8 patients with PCO (presence of polycystic ovaries on Ecografya and/or Laparoscopy) and 8 patients with idiopatic hirsutism (presence of normal morphology ovaries). Basal LH, FSH, E1, E2 and delta 4 levels were also measured. The value of LH delta 2 were more elevated in patients with PCO (p less than 0,0002) than the patients with idiopatic hirsutism. Consequently it as been value of LH delta 2 to discriminate the two different groups of patients. In PCO patients were also found: -a positive linear correlation between LH delta 1 and basal concentration serum of E2 (p less than 0,001); -a significant increase of basal levels serum of delta 4 (p less than 0,02); while the values of basal LH and LH delta 1 were found superior only on 4 of the initial 8 patients, the basal values of E1 and E2 were at the superior found of the norm and basal FSH, FSH delta 1 and FSH delta 2 values were found normals. 相似文献
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Litschauer B Schaller G Wolzt M 《American journal of physiology. Heart and circulatory physiology》2005,289(5):H2120-H2125
The interaction between central opioid activity, sex hormones, and the cardiovascular reactivity to stress is unknown. Twenty-eight healthy postmenopausal women, 16 without, and 12 with hormone replacement therapy (HRT) participated in this randomized, double-blind, cross-over study. The opioid receptor antagonist naloxone or placebo was administered intravenously on 2 different days and mild mental stress was induced by the Stroop Color-Word Test. Cardiovascular responses were assessed noninvasively by impedance cardiography. Stress significantly increased stroke volume, cardiac output, blood pressure, and heart rate, which was not influenced by opioid receptor blockade. Whereas naloxone increased cortisol plasma concentrations irrespective of HRT status, luteinizing hormone concentrations, which were higher in non-HRT compared with HRT women, were increased by naloxone in women with HRT only. These data suggest that the opioidergic tone of the hypothalamus-pituitary-adrenal axis persists in postmenopausal women, irrespective of HRT use, while the opioidergic tone on the hypothalamus-pituitary-gonadal axis seems to depend on an estrogenic milieu. Naloxone does not alter cardiovascular mental stress reactions in postmenopausal women independent of their hormone substitution status. 相似文献
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The effect of depleting tuberoinfundibular dopamine (TIDA) on gonadotropin secretion was studied in rats made hyperprolactinemic by implantation of the prolactin and growth hormone secreting Furth MtTW15 tumor. Implants of the pituitary tumor prevented gonadotropin release in response to castration. Daily injection of 100 mg dl-alpha-methyl-para-tyrosine/kg bw which reduced TIDA levels in tumor bearing rats more than 90% did not restore gonadotropin release. It seems likely that the increased activity of the TIDA system does not mediate the suppression of gonadotropins during chronic hyperprolactinemia. 相似文献
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A single injection of estradiol valerate (EV) to adult female rats induces a persistent anovulatory polycystic ovarian (PCO) condition. During the 8-20-wk interval following EV treatment, this condition is associated with a selective compromise of LH release, decreased pituitary content of LH, and decreased GnRH-stimulated LH secretion. A marked increase in mean plasma concentrations of LH and enhanced LH response to GnRH occur after 20 wk post-EV treatment. Despite this apparent improvement, the PCO condition remains unchanged. The present study was undertaken to elucidate the underlying causes for these spontaneous improvements in LH parameters. We reasoned that these changes may be the result of alterations in 1) pituitary GnRH receptor levels; or 2) the mode of LH secretion, i.e. GnRH-dependent versus GnRH-independent; or 3) post-GnRH receptor events. Hence, we assessed pituitary GnRH receptor concentration as well as the pituitary content of LH and FSH in rats with PCO of 9 wk and 22 wk duration. To examine the possibility of a change in the mode of LH secretion, we examined the effects of in vivo suppression of LH secretion by treatment with a GnRH antagonist [N-Ac-D-Nal1, D-Phe2,3, D-Arg6, Phe7, D-Ala10]-GnRH (GnRH-ANTAG) in the same groups of animals. Mean pituitary weights were greater in the 9-wk-PCO than in the 22-wk-PCO animals. The pituitary concentration of GnRH receptors (on either a weight or milligram pituitary-membrane protein basis) was similar in the 9-wk- and 22-wk-PCO animals. Pituitary LH and FSH contents, however, were significantly higher (5-fold and 2-fold, respectively) in 22-wk-PCO rats compared to the 9-wk-PCO animals.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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R Seghaye E Deflandre G Remacle-Volon J Damas 《Comptes rendus des séances de la Société de biologie et de ses filiales》1986,180(3):386-389
In the rat, previous injection of turpentine reduced carrageenan-induced oedema. Naloxone and nalorphine did not modify the anti-inflammatory effect of this kind of counter-irritation. Morphine had no influence on carrageenan oedema. These results suggest that endogenous endorphins take no part to the anti-inflammatory effect of counter-irritation by turpentine. 相似文献
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de Miranda Cabral Gontijo AM Barreto RE Speit G Valenzuela Reyes VA Volpato GL Favero Salvadori DM 《Mutation research》2003,534(1-2):165-172
Fish blood erythrocytes are frequently used as sentinels in biomonitoring studies. Usually, fish blood is collected by painful cardiac or caudal vein punctures. Previous anesthesia could decrease animal suffering but it is not known at present whether anesthesia can cause confounding effects. Therefore, using the alkaline single cell gel (SCG)/comet assay with blood erythrocytes of the cichlid fish Nile tilapia, we tested for a possible modulation of induced DNA damage (methyl methanesulfonate; MMS) by the anesthetic benzocaine administered by bath exposure (80mg/l for approximately 10min). Furthermore, benzocaine (80-600mg/l) was tested for its genotoxic potential on fish erythrocytes in vitro and for potential interactions with two known genotoxins (MMS and hydrogen peroxide). Our results did neither indicate a significant increase in the amount of DNA damage (even after a 48h follow-up), nor indicated interactions with MMS-induced DNA damage when fish were exposed to benzocaine in vivo. There was also no increase in DNA damage after in vitro exposure of fish erythrocytes to benzocaine. Clear concentration-related effects were observed for the two genotoxins in vitro, which were not significantly altered by the presence of benzocaine. These results suggest that anesthesia of fish does not confound comet assay results and the use of blood samples from anesthetized fish can be recommended with regard to animal welfare. 相似文献
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目的 探讨HOXA10基因在卵巢中颗粒细胞的表达及其与多囊卵巢综合征的关系.方法 采用逆转录聚合酶链反应及免疫印迹法分别测定25例多囊卵巢综合征(PCOS)妇女和32例卵巢功能正常(Non-PCOS)妇女卵巢黄素化颗粒细胞中HOXA10 mRNA和蛋白的表达水平.结果 PCOS妇女黄素化颗粒细胞中HOXA10 mRNA的表达和蛋白的表达均低于Non PCOS妇女(P<0.01,P<0.05).结论 HOXA10基因在卵巢中有表达,PCOS妇女卵巢黄素化颗粒细胞HOXA10 mRNA和蛋白表达水平明显低于Non-PCOS妇女,提示该基因可能参与了PCOS的发生及发展过程. 相似文献
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Grimmichová T Vrbíková J Matucha P Vondra K Veldhuis PP Johnson ML 《Physiological research / Academia Scientiarum Bohemoslovaca》2008,57(Z1):S91-S98
The aim of our study was to evaluate rapid insulin pulses and insulin secretion regularity in fasting state in lean women with polycystic ovary syndrome (PCOS) in comparison to lean healthy women. PCOS (n=8) and controls (n=7) underwent every minute blood sampling for 60 min. Insulin pulsatility was assessed by deconvolution and insulin secretion regularity by approximate entropy methodology. PCOS had higher testosterone (p<0.02), prolactin (p<0.05) and lower sex hormone binding globulin (SHBG) (p<0.0006) levels than controls. Approximate entropy, insulin pulse frequency, mass, amplitude and interpulse interval did not differ between PCOS and controls. PCOS had broader insulin peaks determined by a common half-duration (p<0.07). Burst mass correlated positively with testosterone (p<0.05) and negatively with SHBG (p 0.0004) and common half-duration correlated positively with prolactin (p<0.008) and cortisol levels (p<0.03). Approximate entropy positively correlated with BMI (p<0.04) and prolactin (p<0.03). Lean PCOS patients tended to have broader insulin peaks in comparison to healthy controls. Prolactin, androgens and cortisol might participate in alteration of insulin secretion in PCOS-affected women. Body weight and prolactin levels could influence insulin secretion regularity. 相似文献
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Phencyclidine (PCP) has been shown to stimulate the pituitary-adrenal axis in the rat. The purpose of the present study was to determine whether opiate receptors are involved in this effect by testing whether pretreatment with the opiate antagonist naloxone can antagonize PCP-induced ACTH and corticosterone release. PCP (10.0 mg/kg) produced increases in plasma ACTH and corticosterone 60 min after s.c. administration. Pretreatment with naloxone (2.0 mg/kg s.c.) did not reduce the rise in plasma levels of ACTH or corticosterone produced by PCP. These results indicate that naloxone-sensitive opiate receptors are not involved in the PCP-induced stimulation of the pituitary-adrenal axis in rats. 相似文献
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Linkage analysis in 19 families with autosomal recessive polycystic kidney disease (ARPKD) has shown that ARPKD is not linked to the recently assigned second gene locus for autosomal dominant polycystic kidney disease (ADPKD) on chromosome 4q (PKD2). Thus, there is strong evidence that ADPKD and ARPKD have different gene loci. 相似文献
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Chlordecone does not interfere with hepatic repair after carbon tetrachloride or partial hepatectomy
James A. Dolak Robert S. Britton Eric A. Glende Jr. Richard O. Recknagel 《Journal of biochemical and molecular toxicology》1987,2(1):57-66
The effect of chlordecone (CD) on hepatic repair, measured either as recovery of microsomal enzymatic functions or as the induction of cytosolic thymidine kinase (TK) activity, was evaluated in rats given carbon tetrachloride (CC14). Carbon tetrachloride was administered to CD-potentiated and control animals using doses of this hepatotoxin which produce similar degrees of damage at 24 hours in both groups of animals (6 and 100 μ1 CC14 per 100 g body weight, respectively). Chlordecone had no significant effect on the time course of recovery of microsomal cytochrome P-450 content or glucose-6-phosphatase activity following CC14 administration. Hepatic TK activity was measured 48 hours after CC14 administration as a biochemical index of the hepatic regenerative response. Thymidine kinase activity was increased eightfold in CD-treated rats receiving 6 μ1 CC14 per 100 g body weight, whereas in controls a similar induction of TK activity was produced by 100 μ1 CC14 per 100 g body weight. Therefore, the TK response in CD-treated rats receiving CC14 is appropriate for the amount of damage produced, suggesting that CD does not inhibit the hepatic regenerative response to CC14-induced injury. The effect of CD on hepatic repair was also examined in rats receiving a two-thirds partial hepatectomy. Pretreatment of animals with CD had no significant effect on the increase in TK activity produced 24 hours after partial hepatectomy. These results offer no support for the idea that CD impairs hepatic repair after either partial hepatectomy or CC14 administration. 相似文献
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Desferal is a clinically approved iron chelator used to treat iron overload. Doxorubicin is an anthracycline cancer chemotherapy drug used in the treatment of breast cancer. It can undergo redox cycling in the presence of iron to produce reactive oxygen species. The oxidant-generating activity of doxorubicin is thought to be responsible for the cardiotoxic side effects of the drug, but it is unclear whether it is also required for its anti-tumor activity. To test whether an iron-chelating antioxidant would interfere with the tumor-killing activity of doxorubicin, nude mice were transplanted with xenografts of human breast cancer MDA-MB 231 cells and then treated with doxorubicin and/or desferal. Not only did desferal not interfere with the anti-tumor activity of doxorubicin, it inhibited tumor growth on its own. In vitro studies confirmed that desferal inhibits breast tumor growth. However, it did not induce apoptosis, nor did it induce cell cycle arrest. Instead, desferal caused cytostasis, apparently through iron depletion. The cytostatic activity of desferal was partially ameliorated by pretreatment with iron-saturated transferrin, and transferrin receptor expression on breast cancer cells nearly doubled after exposure to desferal. In contrast to its effect on tumor cells, desferal did not inhibit growth of normal breast epithelial cells. The data indicate that the anti-tumor activity of doxorubicin is not dependent on iron-mediated ROS production. Furthermore, desferal may have utility as an adjunctive chemotherapy due to its ability to inhibit breast tumor growth and cardiotoxic side effects without compromising the tumor-killing activity of an anthracycline chemotherapy drug. 相似文献
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Virendra B. Mahesh Darrell W. Brann 《The Journal of steroid biochemistry and molecular biology》1992,41(3-8):495-513
Recent work from our laboratory suggests that a complex interaction exists between ovarian and adrenal steroids in the regulation of preovulatory gonadotropin secretion. Ovarian estradiol serves to set the neutral trigger for the preovulatory gonadotropin surge, while progesterone from both the adrenal and the ovary serves to (1) initiate, (2) synchronize, (3) potentiate and (4) limit the preovulatory LH surge to a single day. Administration of RU486 or the progesterone synthesis inhibitor, trilostane, on proestrous morning attenuated the preovulatory LH surge. Adrenal progesterone appears to play a role in potentiating the LH surge since RU486 still effectively decreased the LH surge even in animals ovariectomized at 0800 h on proestrus. The administration of ACTH to estrogen-primed ovariectomized (ovx) immature rats caused a LH and FSH surge 6 h later, demonstrating that upon proper stimulation, the adrenal can induce gonadotropin surges. The effect was specific for ACTH, required estrogen priming, and was blocked by adrenalectomy or RU486, but not by ovariectomy. Certain corticosteroids, most notably deoxycorticosterone and triamcinolone acetonide, were found to possess "progestin-like" activity in the induction of LH and FSH surges in estrogen-primed ovx rats. In contrast, corticosterone and dexamethasone caused a preferential release of FSH, but not LH. Progesterone-induced surges of LH and FSH appear to require an intact N-methyl-D-aspartate (NMDA) neurotransmission line, since administration of the NMDA receptor antagonist, MK801, blocked the ability of progesterone to induce LH and FSH surges. Similarly, NMDA neurotransmission appears to be a critical component in the expression of the preovulatory gonadotropin surge since administration of MK801 during the critical period significantly diminished the LH and PRL surge in the cycling adult rat. FSH levels were lowered by MK801 treatment, but the effect was not statistically significant. The progesterone-induced gonadotropin surge appears to also involve mediation through NPY and catecholamine systems. Immediately preceding the onset of the LH and FSH surge in progesterone-treated estrogen-primed ovx. rats, there was a significant elevation of MBH and POA GnRH and NPY levels, which was followed by a significant fall at the onset of the LH surge. The effect of progesterone on inducing LH and FSH surges also appears to involve alpha 1 and alpha 2 adrenergic neuron activation since prazosin and yohimbine (alpha 1 and 2 blockers, respectively) but not propranolol (a beta-blocker) abolished the ability of progesterone to induce LH and FSH surges. Progesterone also caused a dose-dependent decrease in occupied nuclear estradiol receptors in the pituitary.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
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R.Kennedy Keller Glenn D. Swank 《Biochemical and biophysical research communications》1978,85(2):762-768
In order to examine the role of carbohydrate in the secretion of ovalbumin, oviduct minces were incubated in the presence of tunicamycin, an inhibitor of dolichol-mediated glycosylation. Ovalbumin secretion was monitored immunologically and found to be identical, within experimental error, in the absence and presence of tunicamycin. These results, coupled with the recent finding of Palmiter . [Proc. Natl. Acad. Sci. (1978) , 94–98] indicate that neither a transient hydrophobic pre-piece nor carbohydrate is required for ovalbumin secretion. 相似文献