Nodal quasiparticle dynamics in the heavy fermion superconductor CeCoIn5 revealed by precision microwave spectroscopy.

CeCoIn5 is a heavy fermion superconductor with strong similarities to the high-Tc cuprates, including quasi-two-dimensionality, proximity to antiferromagnetism and probable d-wave pairing arising from a non-Fermi-liquid normal state. Experiments allowing detailed comparisons of their electronic properties are of particular interest, but in most cases are difficult to realize, due to their very different transition temperatures. Here we use low-temperature microwave spectroscopy to study the charge dynamics of the CeCoIn5 superconducting state. The similarities to cuprates, in particular to ultra-clean YBa2Cu3O(y), are striking: the frequency and temperature dependence of the quasiparticle conductivity are instantly recognizable, a consequence of rapid suppression of quasiparticle scattering below T(c); and penetration-depth data, when properly treated, reveal a clean, linear temperature dependence of the quasiparticle contribution to superfluid density. The measurements also expose key differences, including prominent multiband effects and a temperature-dependent renormalization of the quasiparticle mass.

Incidence, risk factors, and outcomes of osteonecrosis of the jaw: integrated analysis from three blinded active-controlled phase III trials in cancer patients with bone metastases.

BACKGROUND: Osteonecrosis of the jaw (ONJ) has been reported in patients receiving bisphosphonates for metastatic bone disease. ONJ incidence, risk factors, and outcomes were evaluated in a combined analysis of three phase III trials in patients with metastatic bone disease receiving antiresorptive therapies. PATIENTS AND METHODS: Patients with bone metastases secondary to solid tumors or myeloma were randomly assigned to receive either s.c. denosumab (120 mg) or i.v. zoledronic acid (4 mg) every 4 weeks. On-study oral examinations were conducted by investigators at baseline and every 6 months. Oral adverse events were adjudicated by an independent blinded committee of dental experts. RESULTS: Of 5723 patients enrolled, 89 (1.6%) patients were determined to have ONJ: 37 (1.3%) received zoledronic acid and 52 (1.8%) received denosumab (P = 0.13). Tooth extraction was reported for 61.8% of patients with ONJ. ONJ treatment was conservative in >95% of patients. As of October 2010, ONJ resolved in 36.0% of patients (29.7% for zoledronic acid and 40.4% for denosumab). CONCLUSIONS: In this combined analysis of three prospective trials, ONJ was infrequent, management was mostly conservative, and healing occurred in over one-third of the patients. Educating physicians about oral health before and during bone-targeted therapy may help reduce ONJ incidence and improve outcomes.

Trends in testicular germ cell cancer incidence in Australia.

OBJECTIVE: Although increasing incidence of testicular germ cell cancer has been reported in many developed nations, national estimates for Australia, with histological differentiation, are not currently available. METHODS: Using data from all state and territory population-based cancer registries in Australia, this paper reports on incidence trends for seminomas and non-seminomas in Australia between 1982 and 2004 using Joinpoint and Age-Period-Cohort models. RESULTS: Of the 10,528 testicular germ cell cancers diagnosed during this period, 6086 (58%) were seminomas. Incidence rates have increased (2.6% per year) in Australia since 1982, with the effect stronger among seminomas (3.4% per year) rather than non-seminomas (1.4% per year). There was a strong age effect evident for both subtypes, peaking in the 25-29 year age group for non-seminomas and the 30-34 year age group for seminomas. Non-seminoma rates reflected a significant birth cohort effect, following a U-shaped pattern with the lowest risk among the 1,945 birth cohort. CONCLUSIONS: The differential trends observed for Australia for seminomas and non-seminomas are consistent with those reported for the United States, but slightly different to those reported for Europe. The trends may be at least partly due to changes over time in the prevalence of etiologic or protective factors around the time of birth.

Testicular cancer in twins: a meta-analysis.

In a meta-analysis of testicular cancer in twins, twins had a 30% increased risk (estimate 1.31, 95% CI 1.1-1.6), providing indirect support for the hypothesis that in utero hormone variations influence risk of testicular cancer. The summary-estimate for dizygotic twins was 1.3 (1.0-1.7) and for monozygotic or same sex twins 1.4 (1.2-1.8).

Decreased LH pulsatility during initiation of gonadotropin superovulation treatment in the cow: evidence for negative feedback other than estradiol and progesterone.

LH pulse secretion is suppressed during superovulation of cattle. The objective of this study was to determine how soon after initiation of superovulation treatments this suppressive effect occurs, and to test the hypothesis that decreased LH pulsatility is not related to changes in circulating estradiol or progesterone. Heifers (n = 7/group) were injected with eCG (FOLLIGON: a single injection of 2,500 IU) or twice daily injections of decreasing doses of FOLLTROPIN-V (total equivalent of 280 mg of NIH-FSH-P1) or F.S.H.-P (total equivalent of 28 mg of Armour standard) or saline (time controls), starting on Day 10 (Day 0 = estrus). Blood samples were taken every 10 min for 12 h intervals on the day prior to first injection, at 8 to 20 h and 32 to 44 h after initiation of gonadotropin treatment, and also during prostaglandin (PG)-induced luteolysis. A simple method based on robust statistics and on graphical representations of time series was developed to characterize LH pulses. There was a significant interaction between time and treatment for mean LH, estradiol and progesterone when control and treated groups were analyzed together, and no interaction when only the gonadotropin groups were analyzed together. When compared to pretreatment values, pulse frequency of LH was significantly reduced (P<0.05) in each treatment group, 8 to 20 h and 32 to 44 h following initiation of gonadotropin treatment. Mean LH concentrations were also reduced 32 to 44 h following initiation of treatments (P<0.05). Mean estradiol concentrations increased two to threefold at 8 to 20 h following initiation of superovulation treatments (P<0.05). Progesterone concentrations also increased by 20 or 44 h. There was no significant correlation between estradiol or progesterone and LH pulse frequency, amplitude and mean concentrations at any time in control or superovulated animals. This study demonstrates that superovulation treatment in the cow causes a rapid decrease in pulsatile release of LH and suggests that this effect is not mediated through the negative feedback actions of estradiol and progesterone.

Amisulpride has a superior benefit/risk profile to haloperidol in schizophrenia: results of a multicentre, double-blind study (the Amisulpride Study Group).

In a multicentre, double-blind, flexible-dose study, 199 patients with paranoid schizophrenia or schizophreniform disorders received haloperidol (10-30 mg/d) or amisulpride (400-1200 mg/d) for four months. More patients in the haloperidol group withdrew prematurely (44% vs 26%; P = 0.0077) due to a higher incidence of adverse events. Amisulpride was at least as effective as haloperidol in reducing the Brief Psychiatric Rating Scale (BPRS) total score (-27.3 vs -21.9) (non-inferiority test; P < 0.001). The PANSS positive score improved to a similar extent in both groups whilst improvement in the PANSS negative score was significantly greater with amisulpride (-10.5 vs -7.2; P = 0.01). The percentage of responders on the Clinical Global Impression scale was also significantly greater with amisulpride (71% vs 47%; P < 0.001). Both the Quality of Life Scale (QLS) and the Functional Status Questionnaire (FSQ) improved to a significantly greater extent under amisulpride. Haloperidol was associated with a greater incidence in extrapyramidal symptoms and with a greater increase in the Simpson-Angus score than was seen with amisulpride (0.32 vs 0.02; P < 0.001). In conclusion, amisulpride is globally superior to haloperidol in the treatment of acute exacerbations of schizophrenia and significantly improves patients' quality of life and social adjustment.

Identification and characterization of a new growth hormone-releasing peptide receptor in the heart.

Hexarelin, a synthetic hexapeptide of the growth hormone-releasing peptide (GHRP) family with strong growth hormone (GH)-releasing activity, features protecting activity against postischemic ventricular dysfunction in hearts from GH-deficient and senescent rats. To document whether hexarelin action is mediated through specific cardiac receptors, perfusion of Langendorff rat hearts with hexarelin and binding studies were carried out. In the Langendorff rat heart system, hexarelin induced a dose-dependent increase in coronary perfusion pressure. Nifedipine, chelerythrine, and bisindolylmaleimide partially inhibited the vasoconstriction induced by hexarelin, suggesting that this effect was mediated at least in part by L-type Ca(2+) channels and protein kinase C. In contrast, diclofenac and 1-(7-carboxyheptyl)imidazole were without effect, suggesting that prostaglandins and thromboxanes were not involved in the coronary vasoconstriction induced by hexarelin. To characterize the hexarelin binding sites in the rat heart, [(125)I]Tyr-Bpa-Ala-hexarelin was used as photoactivatable radioligand in saturation and competitive binding studies. We specifically labeled a hexarelin receptor with an M(r) of 84 000 in rat cardiac membranes. Saturation binding curves revealed a single class of binding sites with a K(d) of 14.5 nmol/L and a density of 91 fmol/mg of protein. Competition binding studies gave an IC(50) of 2.9 micromol/L for hexarelin; MK-0677 and EP51389, both potent GH secretagogues, did not displace the binding of the photoactivatable derivative from rat cardiac membranes. Interestingly, both compounds were devoid of any vasoconstrictive activity. These results suggest the existence of a new class of hexarelin receptor in the heart, whose role in the regulation of the coronary vascular tone is yet to be determined.

Effects of superovulation on endogenous LH secretion in cattle, and consequences for embryo production.

Stimulation of follicular growth during superovulation is achieved by the injection of FSH or compounds with high FSH-bioactivities. However, some LH-activity is required for follicle maturation. It is of relevance to evaluate, therefore, the effect of superovulatory treatments on endogenous LH secretion. Luteinizing hormone is secreted in discrete pulses, and the pattern of pulsatile LH secretion during superovulation is reviewed. Four of five published studies have shown that LH pulse frequency is significantly reduced by injection of eCG or FSH preparations. This suppression appears within 8 h of treatment Effects of superovulation on LH pulse amplitude are less consistent. The reasons for the decrease in pulse frequency have been investigated, and although the answer is not definitive, it would seem that increased follicular estradiol, acting perhaps in synergism with progesterone, may play a role. Changes in plasma progesterone concentrations are not related to changes in LH pulse frequency. What is the significance of decreased LH pulse frequency? We attempted to investigate this by inducing LH pulses during superovulation, but the result was a major reduction in ovulation rate. More research is required to determine if modification of endogenous LH secretion can improve superovulatory responses.

Prostaglandin G/H synthase-2 is expressed in bovine preovulatory follicles after the endogenous surge of luteinizing hormone.

To determine whether prostaglandin G/H synthase-2 (PGHS-2) induction occurs under physiological conditions, heifers were ovariectomized and preovulatory follicles were isolated 0 (n = 4), 18 (n = 4), and 24 h (n = 4) after the onset of estrus. The time of the LH surge was determined in blood samples collected every 4 h pre- and postestrus. Preparations of follicle wall and isolated theca interna and granulosa cells were analyzed for PGHS-2 protein and mRNA by immunoblot and Northern blot, respectively. Immunohistochemistry was used to document the in situ localization of PGHS-2 protein, and follicular fluid concentrations of prostaglandin (PG) E2 and PGF2alpha were determined to monitor changes in PG synthetic activities. Results showed that PGHS-2 mRNA (4.0 kilobases) and protein (74000 Mr) were absent in preovulatory follicles isolated at the onset of estrus, low in follicles obtained 18 h after estrus (16.0 +/- 1.2 h post-LH surge), and markedly induced 24 h postestrus (20 +/- 0 h post-LH surge). Immunoblot and immunohistochemical analyses revealed that PGHS-2 protein was selectively induced in granulosa cells. Follicular fluid concentrations of PGE2 and PGF2alpha increased significantly (p < 0.01) between 0 and 24 h after estrus (from 2.8 +/- 0.2 to 87.9 +/- 30.9 ng/ml for PGE2; from 0.05 +/- 0.02 to 68.9 +/- 23.6 ng/ml for PGF2alpha). Collectively, these results clearly demonstrate that the induction of PGHS-2 in bovine preovulatory follicles is a physiological event that occurs after the endogenous LH surge.

The role of pregnenolone-metabolizing enzymes in the regulation of oestradiol biosynthesis during development of the first wave dominant follicle in the cow.

During the luteal phase in the cow, a first-wave dominant follicle grows to reach ovulatory size, but then ceases to grow, becomes no longer dominant and enters a phase of slow regression. During this growth transition, the concentration of oestradiol has been shown to decrease in follicular fluid. The objective of this study was to determine if follicular fluid oestradiol concentrations are regulated by the activity of three major steroidogenic enzymes, namely P450-aromatase (P450-arom), 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) and 17 alpha-hydroxylase C-17,20 lyase cytochrome P450 enzyme (P450-17 alpha) measured in granulosa and theca cells isolated from individual first-wave dominant follicles. Follicle growth and state of dominance was assessed by ultrasonography and follicles were classified as growing-dominant (GD, n = 6), non-growing-dominant (NGD, n = 8) or non-growing-non-dominant (NGD, n = 6). Mean follicular fluid concentrations of oestradiol were higher in GD than in NGD or NGND follicles (511 +/- 98 versus 136 +/- 16 and 20 +/- 11 nmol/l respectively). Oestradiol was not correlated with P450-arom in any of the three groups. In GD follicles, oestradiol was positively correlated with pregnenolone concentration but neither was correlated with granulosa or theca 3 beta-HSD activity or with theca P450-17 alpha activity. In NGD follicles, oestradiol was negatively correlated with theca 3 beta-HSD activity and pregnenolone was negatively correlated with granulosa 3 beta-HSD activity. In NGND follicles, oestradiol was positively correlated, and pregnenolone was negatively correlated with theca 3 beta-HSD and P450-17 alpha activities. These studies demonstrated that pregnenolone supply is the principal regulating factor of oestradiol output during follicle dominance and during the loss of dominance but that the levels of P450-17 alpha and 3 beta-HSD activity become rate-limiting when the follicle is no longer dominant.

Ultrasonography and endocrinology of ovarian dysfunctions induced in heifers with estradiol valerate.

This study monitored the long-term follicular dynamics and changes in ovarian steroid hormones associated with an experimental model of cystic ovarian degeneration (COD) in the heifer. In the treated group (n = 7), Holstein heifers received a single injection of 500 microg of cloprostenol (prostaglandin F2a, PG) and 5 mg of estradiol valerate (EV) on either Day 17, 18 or 19 of the estrous cycle. The control group (n = 7) received only PG. Transrectal ultrasound was performed daily, beginning 8 to 10 d before injection and continuing until a return to normal cyclicity (40 to 74 d). Blood samples were taken twice daily over the same period. The EV disrupted the normal follicular development as well as the plasma progesterone and estradiol profiles of 6/7 heifers in the treated group. Two different types of responses were observed. The Type-I response (n = 2) was characterized by a premature ovulation followed by a corpus luteum (CL) which persisted for over 30 d. The Type-II response (n = 4) was characterized by anovulation followed by the emergence of a large ovarian structure which could further be subtyped. In Type- IIA (n = 2), this follicle ovulated at an exaggerated size of 19 or 24 mm (mean diameter of controls: 13.4 +/- 2.7 mm). The subsequent cavernous CL was very large at 35 and 37 mm (mean diameter of CL in controls: 23.8 +/- 2.0 mm). In Type- IIB (n = 1), the follicle present at the time of injection continued to grow and became a luteinized cyst. In Type-IIC (n = 1), several waves of follicular cysts developed and persisted for 52 d. This study suggests that EV induces a range of ovarian dysfunctions including different forms of COD. The individual differences in the stage of folliculogenesis at the time of injection of EV may be responsible for the different types of responses.

Ultrasonographic analysis of gestation in mink (Mustela vison).

Mink are seasonal breeders that display an obligate delay preceding implantation and a post implantation gestation of 31 d. The purpose of this study was to evaluate gestational parameters in mink by ultrasonography. A total of 92 female mink were mated twice during the period from March 2 to 20. The mink were scanned once and allowed to whelp (n=55); or scanned at 3 to 5-d intervals until parturition (n=13); or immediately subjected to autopsy (n=24) after scanning. Embryonic age was calculated from the date of parturition or from crown rump length. Uterine swelling diameter and fetal head size were correlated with embryonic age. The gestational sac grew rapidly once implantation had occurred. Uterine swellings of 4 to 5 mm in diameter were found on Days 2 to 4 post implantation and increased through Days 18 to 20, at which time they began to elongate due to the longitudinal growth of the fetus. Fetal cardiac activity could be detected on Days 10 to 12 post implantation in live embryos. The heart frequency was 198 +/- 3.0 beats per minute and did not vary from Days 12 to 30 post implantation. Fetal head diameter of 5 mm was first detected on Day 19 post implantation and grew gradually to 9 to 10 mm at parturition. It was not possible to accurately assess the number of conceptuses in utero. We conclude that ultrasonography can be employed in mink to diagnose pregnancy, to predict the parturition date and to determine the presence of live fetuses.

Comparison of hormonal and histological changes during follicular growth, as measured by ultrasonography, in cattle.

The aim of the study was to compare histological and endocrinological indices of ovarian follicle health in cattle with monitoring of follicle growth and regression by ultrasound imaging in vivo. Ultrasound scanning was performed daily. Follicles were obtained at ovariectomy; follicular fluid was collected for assay, and the degree of atresia was assessed histologically. Histological atresia was correlated with growth patterns when anovulatory growing and regressing follicles were compared (P < 0.05), but was not different between growing and static follicles. Oestradiol concentrations were lower in static than in growing follicles, although the difference was not significant (35 +/- 7 versus 260 +/- 120 ng ml-1; P < 0.08), and were significantly lower in regressing follicles (7 +/- 5 ng ml-1; P < 0.05). Oestradiol concentrations were significantly lower in histologically atretic than in nonatretic follicles (16 +/- 8 versus 282 +/- 132 ng ml-1; P < 0.05), but were not different between nonatretic and early atretic follicles (P > 0.05). There was a significant negative correlation between oestradiol concentration and the number of days the follicle was visible by ultrasound (r = -0.71; P < 0.001). Concentrations of progesterone in follicular fluid were correlated with the number of days the follicles were detected (r = 0.61; P < 0.01) and were higher in regressing than in growing follicles (122 +/- 71 versus 48 +/- 13 ng ml-1; P < 0.05) but not significantly higher in atretic compared with nonatretic follicles (129 +/- 102 versus 53 +/- 15 ng ml-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Decreased pulsatile LH secretion in heifers superovulated with eCG or FSH.

This study was designed to test the hypothesis that treatment with super-ovulatory drugs suppresses endogenous pulsatile LH secretion. Heifers (n=5/group) were superovulated with eCG (2500 IU) or FSH (equivalent to 400 mg NIH-FSH-P1), starting on Day 10 of the estrous cycle, and were injected with prostaglandin F(2alpha) on Day 12 to induce luteolysis. Control cows were injected only with prostaglandin. Frequent blood samples were taken during luteolysis (6 to 14 h after PG administration) for assay of plasma LH, estradiol, progesterone, testosterone and androstenedione. The LH pulse frequency in eCG-treated cows was significantly lower than that in control cows (2.4 +/- 0.4 & 6.4 +/- 0.4 pulses/8 h, respectively; P<0.05), and plasma progesterone (3.4 +/- 0.4 vs 1.8 +/- 0.1 ng/ml, for treated and control heifers, respectively; P<0.05) and estradiol concentrations (25.9 +/- 4.3 & 4.3 +/- 0.4 pg/ml, for treated and control heifers, respectively; P<0.05) were higher compared with those of the controls. No LH pulses were detected in FSH-treated cows, and mean LH concentrations were significantly lower than those in the controls (0.3 +/- 0.1 & 0.8 +/- 0.1, respectively; P<0.05). This suppression of LH was associated with an increase in estradiol (9.5 +/- 1.4 pg/ml; P<0.05 compared with controls) but not in progesterone concentrations (2.1 +/- 0.2 ng/ml; P>0.05 compared to controls). Both superovulatory protocols increased the ovulation rate (21.6 +/- 3.9 and 23.0 +/- 4.2, for eCG and FSH groups, respectively; P>0.05). These data demonstrate that super-ovulatory treatments decrease LH pulse frequency during the follicular phase of the treatment cycle. This could be explained by increased steroid secretion in the eCG-treated heifers but not in FSH-treated animals.

Direct radioimmunoassay of progesterone in bovine plasma using danazol (17-alpha-2,4-pregnadien-20-yno(2,3-d)isoxazol-17-ol) as a displacing agent.

The majority of progesterone in plasma is bound to cortisol-binding globulin and albumin carrier proteins. In the determination of plasma progesterone concentration by radioimmunoassay (RIA), it is necessary to remove these carrier proteins or displace the hormone from them. In the present study, we have examined the suitability of danazol (17-alpha-2,4-pregnadien-20-yno(2,3-d)isoxazol-17-ol), a synthetic steroid, to displace progesterone from plasma proteins in a direct RIA of bovine plasma. Accordingly, the progesterone content of bovine plasma samples was measured with a RIA using danazol as a displacing agent (direct RIA) and compared with results obtained with a RIA incorporating a preliminary solvent extraction step (extraction RIA). Danazol did not alter the standard curve for progesterone. Sensitivity (ED80) of the direct RIA (9.8 pg/tube) was comparable to that of the extraction RIA (10.3 pg/tube). Results for progesterone assayed in the direct RIA correlated well (r = 0.99) with the results obtained with the extraction RIA. The direct RIA was shown to be accurate; the mean recovery of known amounts of progesterone added to a sample of pooled bovine plasma was 98.5% +/- 3.29 (SEM). The direct RIA intra-assay coefficient of variation (CV) RIA for samples within the low concentration range (0.1-1.0 ng/mL), the medium concentration range (1.0-3.0 ng/mL) and the high concentration range (3.0-6.0 ng/mL) of progesterone were 8.1%, 8.3% and 7.73%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Alterations in gonadotropin-releasing hormone-dependent gonadotropin secretion in rats with polycystic ovaries.

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)

[Legal and illicit drugs: diffusion of health information in schools. Results of cross-sectional epidemiological survey carried out among 663 adolescents in high schools in Le Havre]. / Drogues licites et illicites: diffusion de l'information sanitaire en milieu scolaire. Résultats d'une enquête épidémiologique transversale réalisée auprès de 663 collégiens du Havre.

In 1988, a cross-sectional study was undertaken in secondary modern schools from the city of Le Havre in order to assess the spread of health education regarding licit and illicit drugs and prepare a pedagogical kit including adolescent opinions on the subject. Through the school system, more than one adolescent out 5 had been taught about tobacco or alcohol, and 11% about illicit drugs. Only 6% had been informed about all 3 subjects, and 70% had not received any information. Regarding alcohol and tobacco, health education was positively appreciated by adolescents. Information related to potential health risk constituted the main source of satisfaction. Lastly, 62% of the adolescents were ready to set up a health promotion program on illicits drugs. This choice was not influenced by age, sex or school performance.

The role of aberrant hypothalamic opiatergic function in generating polycystic ovaries in the rat.

Treatment of adult female rats with estradiol valerate produces an intractable hypothalamic impairment that ultimately results in anovulatory acyclicity and polycystic ovaries. Evidence from our laboratory suggests that the hypothalamic impairment compromises regulation of the endogenous opioid system engendering a persistent opiatergic suppression of gonadotropin-releasing hormone secretion, which is subsequently reflected in a chronically low pituitary content of gonadotropin-releasing hormone receptors. If such is the case, inhibition of opiatergic transmission should improve the gonadotropin-releasing hormone pattern resulting in an improvement in the pituitary content of gonadotropin-releasing hormone receptors, and in an amelioration of the polycystic condition. We, therefore, treated rats with the polycystic ovarian condition, with daily injections of naltrexone. Within 1 week, there was a significant increase in the pituitary content of gonadotropin-releasing hormone receptors and a marked improvement in ovarian morphology, indicating that the hypothalamic opiatergic system is chronically active, and contributes significantly to the polycystic ovarian condition.

Reversed-phase liquid chromatography of radiolabeled peptides using a C18 guard-PAK precolumn system.

In order to avoid radioactive contamination of high-performance liquid chromatography columns and injectors, we have investigated the use of a Guard-PAK precolumn system for the chromatography of [125I] labeled peptides. Two gonadotropin-releasing hormone analogs: 1) [D-Ala6-des-Gly10]-GnRH (GnRH-[Ala6]) and 2) [D-Ser(TBu)6-des-Gly10]-GnRH (GnRH-[Ser6]) and rat prolactin (r-PRL) were radiolabeled with 125I and subjected to reversed-phase liquid chromatography using a C18 Guard-PAK precolumn system. Major peak fractions of purified [125I]GnRH-[Ala6], [125I]GnRH-[Ser6], and [125I]r-PRL eluted at 24%, 28%, and 55% acetonitrile, respectively. Purified [125I]GnRH analogs showed specific high affinity binding to rat anterior pituitary gland membranes (specific activity: 1500-1700 Ci/mmol). Purified [125I]r-PRL showed high affinity binding to r-PRL antibody by RIA (specific activity: 70-75 microCi/micrograms). This rapid and efficient chromatographic method should be useful in the separation of a wide range of radiolabeled protein and peptide molecules.

Pituitary gonadotropin-releasing hormone receptor content in rats with polycystic ovaries.

A single injection of estradiol valerate (EV) induces, after a lag period of 4-6 wk, a chronic anovulatory polycystic ovarian (PCO) condition in adult rats. This condition is associated with a selective compromise of luteinizing hormone (LH) release and/or synthesis reflected in low basal serum LH concentrations, decreased pituitary content of LH, and decreased gonadotropin-releasing hormone (GnRH)-stimulated LH secretion. The present study was undertaken to determine to what extent the aberrant LH release in rats with PCO could be related to alterations in pituitary content of GnRH receptors. Pituitary GnRH-receptor content was assessed by the evaluation of saturation binding of a GnRH analog, [125I]-D-Ala6-des-Gly10-GnRH, to pituitary membrane preparations. The receptor content of pituitaries from rats with PCO was compared to that obtained from intact animals at estrus and diestrus. Receptor levels in ovariectomized normal rats and rats with PCO were also assessed. The pituitary GnRH receptor content in PCO rats was similar to that observed in normal controls at estrus and was significantly lower than that for rats at diestrus. Although a twofold increase in pituitary GnRH receptor content was observed at 28 days following the castration of control rats, GnRH receptor content in the pituitaries of PCO rats, at 28 days following ovariectomy, remained unchanged. Although, castration-induced elevations in mean serum LH and follicle-stimulating hormone (FSH) concentrations were observed in both the PCO and control animals, the rise in both gonadotropins was significantly attenuated in the PCO-castrates when compared to the ovariectomized controls. Since GnRH is a major factor in the regulation of pituitary GnRH receptor content, these findings suggest that hypothalamic GnRH release is impaired in rats with PCO and that this impairment is independent of any influences from the polycystic ovaries.