References of "Franchimont, P"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailPlasma Estradiol Concentrations and Pharmacokinetics Following Transdermal Application of Menorest 50 or Systen (Evorel) 50
Reginster, Jean-Yves ULg; Albert, Adelin ULg; Deroisy, Rita ULg et al

in Maturitas (1997), 27(2), 179-86

OBJECTIVES: In order to compare the pharmacokinetics of two transdermal estrogen replacement therapy (ERT) systems designed to release 50 micrograms 17 beta-estradiol/day, two studies were performed in ... [more ▼]

OBJECTIVES: In order to compare the pharmacokinetics of two transdermal estrogen replacement therapy (ERT) systems designed to release 50 micrograms 17 beta-estradiol/day, two studies were performed in healthy postmenopausal volunteers. METHODS: Both studies had a cross-over design and incorporated a 1-week wash-out period between treatments. In the first study, Menorest 50 and Systen 50 (Evorel 50) were compared over four days of application in 30 women. In the second, 13 women wore each of the two systems for a total of 12 days each (three patches each for 4 days), and comparison was made during the third patch period (steady state, between days 8 and 12). Plasma 17 beta-estradiol levels were assayed using specific direct radioimmunoassays, and pharmacokinetic parameters were calculated by standard methods. All the samples of the first study were re-analysed using a different radioimmunoassay and the results of both assays were compared. RESULTS: In both studies, plasma 17 beta-estradiol levels rose at a comparable rate and reached similar peak levels with each of the two formulations. Levels then remained relatively constant throughout both evaluation periods with Menorest 50, but began to decline after 12 hours in the first study and after 30 h under steady state conditions in the second study with Systen 50. The difference between the two products was statistically significant in both studies. Analysis of pharmacokinetic parameters confirmed the greater bioavailability of Menorest 50. In addition, 17 beta-estradiol levels remained within the suggested therapeutic ranges for relief of acute symptoms and protection against osteoporosis for longer periods of time with Menorest 50 than with Systen 50. CONCLUSION: Since the acute efficacy, long-term protective effects, side effects and risks associated with ERT may depend on critical threshold plasma levels, much attention should be paid to the pharmacokinetic profiles of different formulations. The comparison of these two different radioimmunoassays demonstrates the comparability of their results. [less ▲]

Detailed reference viewed: 24 (1 ULg)
Full Text
Peer Reviewed
See detailPlasma Concentration of Estradiol Following Transdermal Administration of Systen 50 or Menorest 50
Reginster, Jean-Yves ULg; Albert, Adelin ULg; Deroisy, Rita ULg et al

in Scandinavian Journal of Rheumatology. Supplement (1996), 103

Circulating levels of 17 beta estradiol (E2) following the administration of fixed doses of E2, show a great variability in kinetics depending upon the product administrated, the routes of administration ... [more ▼]

Circulating levels of 17 beta estradiol (E2) following the administration of fixed doses of E2, show a great variability in kinetics depending upon the product administrated, the routes of administration, and the interindividual variations in absorption and metabolism. This might have important implications both in terms of tolerance and effectiveness. Two new forms of transdermal E2 (SYSTEN Cilag and MENOREST Rhone-Poulenc Rorer) have been recently accepted in Europe for the treatment of climacteric symptoms. The present study was undertaken to compare the pharmacokinetic characteristics of plasma E2 profile under these two drugs. It was carried out in 30 healthy postmenopausal volunteers according to good clinical practice after informed consent, as a single blind, randomised, cross-over study during the classical wearing period of 4 days. Plasma E2 concentration was determined 24 hours before, 1/2 hour before and then 2, 4, 8, 12, 24, 48, 72, 84, 96 hours after the first patch administration. E2 measurement was performed using a specific direct radioimmunoassay developed in the FRH laboratories. The main criteria for this method were an intraassay coefficient of variation (CV) less than 6%, an interassay CV less than 8% in a concentration range of 15-140 pg/ml and a quantitative detection limit (LOQ) of 2.7 pg/ml with a 20% CV. The following kinetic parameters were analysed: C(max), C(mean), C96 and MRT. The bioequivalence was assessed by analysis of variance of C(max), C(mean), C96 and AuC after logarithmic transformation, complemented by Westlake test (95%). Data show that these two products are identical in terms of C(max) but C(mean), C96 and AuC are statistically greater when MENOREST 50(R) is administered; furthermore, E2 levels decrease more rapidly and more deeply with SYSTEN 50 than MENOREST 50. The differences of pharmacokinetic profiles after administration of two different forms of the same dose of 50 micrograms transdermal 17 beta estradiol might have important medical consequences. [less ▲]

Detailed reference viewed: 20 (7 ULg)
Full Text
Peer Reviewed
See detailPrevention of Postmenopausal Bone Loss by Rectal Calcitonin
Reginster, Jean-Yves ULg; Jupsin, Isabelle ULg; Deroisy, Rita ULg et al

in Calcified Tissue International (1995), 56

A group (150) of healthy women, who had been menopausal for less than 5 years and who had never received any form of treatment to prevent bone loss were entered into a randomized, controlled study ... [more ▼]

A group (150) of healthy women, who had been menopausal for less than 5 years and who had never received any form of treatment to prevent bone loss were entered into a randomized, controlled study comprising three arms. They were randomly allocated to the double-blind administration of five suppositories per week containing either 100 IU of salmon calcitonin or a placebo, or to a group receiving a suppository containing 200 IU of salmon calcitonin three times per week. All women received 500 mg/day of calcium supplementation. After 12 months, bone mineral density (BMD) of the spine, measured by dual energy X-ray absorptiometry, decreased significantly (P < 0.01) in the placebo group by 3.1% (SD: 3.6%) but did not change in the two calcitonin groups [+1.3% (3.5%) with 100 IU/day and +2.3% (4.0%) with 200 IU 3/week]. The differences in response between the placebo group and the two calcitonin groups were significant (P < 0.05), but the difference between the two regimens of calcitonin administration was not. No differences appeared among the three groups for the response at the level of the hip. Evolution of biochemical markers reflecting bone turnover did not differ significantly among groups. Nearly 40% of the women withdrew prematurely because of local (rectal or intestinal) intolerance to repetitive suppositories, with a nonsignificantly different frequency in the placebo or calcitonin groups. We conclude that rectal calcitonin might be an interesting preventive approach against trabecular postmenopausal bone loss but that long-term acceptability of suppositories should be evaluated in view of each patient's sensibility or cultural background. [less ▲]

Detailed reference viewed: 6 (2 ULg)
Full Text
Peer Reviewed
See detailA Double-Blind, Placebo-Controlled, Dose-Finding Trial of Intermittent Nasal Salmon Calcitonin for Prevention of Postmenopausal Lumbar Spine Bone Loss
Reginster, Jean-Yves ULg; Deroisy, Rita ULg; Lecart, M. P. et al

in American Journal of Medicine (1995), 98(5), 452-8

PURPOSE: Nasal administration of salmon calcitonin (SCT) has been suggested for preventing trabecular bone loss during the first years following the menopause, but no conclusive evidence has appeared ... [more ▼]

PURPOSE: Nasal administration of salmon calcitonin (SCT) has been suggested for preventing trabecular bone loss during the first years following the menopause, but no conclusive evidence has appeared about the minimal effective dose. Since nasal calcitonin is highly expensive, it makes sense to define this dose. PATIENTS AND METHODS: We performed a double-blind, placebo-controlled, randomized, single-center study with a 3-arm parallel-group design. The subjects were 251 healthy women who had experienced natural menopause within the past 6 to 72 months and were not affected by any diseases or treatments that interfere with calcium metabolism. They were randomly allocated in groups of 6 to receive intranasal SCT 50 IU (n = 84), SCT 200 IU (n = 84), or placebo (n = 83). All treatments were given on 5 consecutive days per week. Statistical analysis was based on two populations: intention-to-treat (IT) and valid completers (VC). The main assessments performed were bone mineral density of the lumbar spine (LSBMD) and biochemical parameters reflecting bone turnover (serum alkaline phosphatase, urinary calcium/creatinine, and hydroxyproline/creatinine ratios). RESULTS: Changes over the treatment period were comparable in the IT and VC populations. In the group receiving the placebo, LSBMD decreased from baseline to end point by a mean of 6.28% (95% confidence interval [CI] -7.69 to -4.89) in the IT population and 6.98% (95% CI -8.86 to -5.11) in the VC population (P = 0.0001, end LSBMD versus baseline LSBMD). LSBMD increased slightly with the 50-IU/d dose of SCT, by 0.82% (95% CI -0.26 to 1.89) in the IT population, and 0.51% (95% CI -0.69 to 1.72) in the VC (P = NS, versus baseline). Subjects who received SCT 200 IU/d experienced significant increases of 2.03% (95% CI 0.92 to 3.15) in the IT population and 2.26% (95% CI 1.01 to 3.51) in the VC (both P = 0.001). The difference between the evolution of the combined groups receiving nasal SCT and the group treated with the placebo was highly significant (P = 0.0001). No significant changes were recorded in biochemical parameters reflecting bone turnover. CONCLUSIONS: SCT 50 IU/d administered nasally and intermittently appears to prevent lumbar bone loss in nonobese early postmenopausal women. [less ▲]

Detailed reference viewed: 9 (2 ULg)
Full Text
Peer Reviewed
See detailChanges in Bronchial Responsiveness, Circulating Leucocytes and Ex Vivo Cytokine Production by Blood Monocytes after Paf Inhalation in Allergic Asthmatics
Louis, Renaud ULg; Degroote, D.; Bury, Thierry ULg et al

in European Respiratory Journal (1995), 8(4), 611-8

We investigated the effects of inhaled platelet-activating factor (PAF) on methacholine bronchial responsiveness, circulating leucocyte counts, and ex vivo tumour necrosis factor alpha (TNF alpha) and ... [more ▼]

We investigated the effects of inhaled platelet-activating factor (PAF) on methacholine bronchial responsiveness, circulating leucocyte counts, and ex vivo tumour necrosis factor alpha (TNF alpha) and interleukin-1 (IL-1) production from blood monocytes in eight allergic asthmatics. Bronchial responsiveness was defined as the provocative concentration of methacholine causing a 20% decrease in forced expiratory volume in one second (PC20). Circulating leucocytes were counted by means of an automatic haemocytometer, and cytokines were measured with specific immunoassays. The different variables were measured before and 4, 24, 48, 72 and 168 h after a PAF (225 micrograms), a lyso-PAF (225 micrograms) and a saline bronchial challenge. When compared with lyso-PAF and saline, inhalation of PAF resulted in a significant decrease in PC20 over a period of one week. Two falls in bronchial responsiveness were identified, the first by 4 h and the second beginning 48 h and reaching a maximum by 168 h. The increases in spontaneous TNF alpha and IL-1 production which occurred during the week after both PAF, lyso-PAF and saline, did not differ significantly. Likewise, the changes in circulating neutrophil counts, characterized by a transient rise by 4 h after PAF and lyso-PAF but not saline, followed by a fall by 24 h and a persistent decrease until 168 h, were not significantly different after PAF, lyso-PAF and saline. On the other hand, in comparison with lyso-PAF and saline, inhaled PAF caused a significant protracted augmentation in circulating eosinophil counts, which was maximal by 48 h but did not correlate with the delayed decline in PC20.(ABSTRACT TRUNCATED AT 250 WORDS) [less ▲]

Detailed reference viewed: 13 (3 ULg)
Full Text
Peer Reviewed
See detailLong-Term Performance in Vitro and in Vivo of Dual-Energy X-Ray Absorptiometry
Reginster, Jean-Yves ULg; Deroisy, Rita ULg; Zegels, Brigitte ULg et al

in Clinical Rheumatology (1995), 14(2), 180-6

Dual-energy X-ray absorptiometry (DXA) is actually considered as one of the most appropriate techniques for measuring bone mineral content (BMC) and bone mineral density (BMD). An anthropomorphic phantom ... [more ▼]

Dual-energy X-ray absorptiometry (DXA) is actually considered as one of the most appropriate techniques for measuring bone mineral content (BMC) and bone mineral density (BMD). An anthropomorphic phantom and a 25-year-old girl were repeatedly measured, 160 times and 50 times respectively, over an 18-month period to investigate performance in vitro and in vivo of a commercial DXA equipment (HOLOGIC QDR 1000). DXA is a highly accurate technique, the BMC and BMD determinations only overestimated the exact value of the phantom by 0.20% and 0.51% respectively. In vivo long-term (18 months) reproducibility of BMD of the spine is characterized by an interassay coefficient of variation (CVt) of 0.8% while, for the different regions of interest of the hip, BMD CVt varies from 1.1% (total zone) to 5.3% (Ward's triangle). In the subject tested, BMD sensitivity for changes of 2.2% at the lumbar spine and 3% at the hip were recorded. [less ▲]

Detailed reference viewed: 7 (4 ULg)
Peer Reviewed
See detailEndogenous Glutamate Involvement in Pulsatile Secretion of Gonadotropin-Releasing Hormone: Evidence from Effect of Glutamine and Developmental Changes
Bourguignon, Jean-Pierre ULg; Gerard, Arlette ULg; Alvarez Gonzalez, Maria-Luz ULg et al

in Endocrinology (1995), 136(3), 911-6

The secretion of GnRH can be stimulated by glutamate (GLU) and GLU agonists, whereas GLU receptor antagonists inhibit GnRH. Using 6-diazo-5-oxo-L-norleucine (DON), an inhibitor of glutaminase, we aimed to ... [more ▼]

The secretion of GnRH can be stimulated by glutamate (GLU) and GLU agonists, whereas GLU receptor antagonists inhibit GnRH. Using 6-diazo-5-oxo-L-norleucine (DON), an inhibitor of glutaminase, we aimed to study the involvement of endogenous GLU in GnRH secretion through the effects of impaired GLU biosynthesis from its precursor glutamine (GLN). GnRH secretion by hypothalamic explants of male rats, aged 15 and 50 days, was compared, because the frequency of spontaneous GnRH secretory pulses showed a 2-fold increase between those two ages. Using explants of 50-day-old rats, GLN elicited GnRH secretion in a similar dose-related manner as GLU. DON prevented GLN-evoked secretion of GnRH, whereas the effect of GLU was not altered. DON also markedly inhibited spontaneous pulsatile secretion of GnRH and the secretory response to veratridine, a Na+ channel opener. The inhibitory effect of DON on veratridine-evoked secretion of GnRH was directly related to the duration of exposure to DON and the frequency of GnRH secretory episodes. Using explants of 15-day-old rats, GLN could elicit GnRH release, although this response was lower than GLU-evoked secretion of GnRH. The DON concentrations required for inhibition of veratridine-evoked secretion of GnRH were lower at 15 days than at 50 days. These data indicate that 1) GLU biosynthesis from GLN is a prerequisite to the physiological mechanism of pulsatile GnRH secretion; and 2) inhibition of veratridine- or GLN-induced secretion of GnRH requires higher DON concentrations after the onset of puberty than before. This suggests that glutaminase, the enzyme controlling GLU biosynthesis from GLN, shows increased activity after the onset of puberty when the frequency of pulsatile GnRH secretion is increased as well. [less ▲]

Detailed reference viewed: 18 (1 ULg)
Full Text
Peer Reviewed
See detailInvestigation of the Relationship between Osteoporosis and the Collagenase Gene by Means of Polymorphism of the 5'upstream Region of This Gene
Thiry-Blaise, L. M.; Taquet, A. N.; Reginster, Jean-Yves ULg et al

in Calcified Tissue International (1995), 56

Osteoporosis is a slowly progressing disease resulting from an imbalance between bone accretion and degradation. As interstitial collagenase is a key enzyme in the degradation of bone matrix, we ... [more ▼]

Osteoporosis is a slowly progressing disease resulting from an imbalance between bone accretion and degradation. As interstitial collagenase is a key enzyme in the degradation of bone matrix, we investigated a possible relationship between the collagenase gene and osteoporosis. Analysis of an amplified genomic DNA fragment from -524 to +52 by denaturing gradient gel electrophoresis and sequencing allowed us to detect three dimorphic sites upstream of base -300, one of them leading to a BanI restriction site. None of the sites could be directly associated with osteoporosis. The allele frequencies of the three dimorphic sites were estimated. The interallelic ratios were high, thus providing new useful genetic markers for linkage analysis. When comparing these ratios in osteoporotic and nonosteoporotic subjects, no significant differences could be observed. [less ▲]

Detailed reference viewed: 7 (2 ULg)
Peer Reviewed
See detailInteractions between IL-1bêta, IL-6, IL-8 and LIF produced by human chondrocytes
Henrotin; Franchimont, P; Reginster, Jean-Yves ULg

in The Official EULAR Journal for Education and Information (1995), 24

Detailed reference viewed: 13 (1 ULg)
Peer Reviewed
See detailDe réels progrès ont-ils été faits dans le traitement de l'ostéoporose ?
Reginster, Jean-Yves ULg; DEROISY, Rita ULg; Franchimont, P

in Medi-Sphere (1995), 39

Detailed reference viewed: 10 (2 ULg)
Full Text
Peer Reviewed
See detailInfluence de la densité osseuse généralisée en implantologie orale
PTAK, Jean ULg; Legrand, Roman; Albert, Adelin ULg et al

in Actualités Odonto-Stomatologiques (1995), 189

Detailed reference viewed: 9 (1 ULg)
Full Text
Peer Reviewed
See detailTraitement de l'ostéoporose: données actuelles et perspectives
Reginster, Jean-Yves ULg; Deroisy, Rita ULg; Franchimont, P.

in Revue du Rhumatisme (1994), 61(10, Pt 2), 155-164

Postmenopausal osteoporosis is characterized not only by a reduction in bone mass but also by bone microarchitecture alterations, which result in greater bone frailty and in an increased fracture risk ... [more ▼]

Postmenopausal osteoporosis is characterized not only by a reduction in bone mass but also by bone microarchitecture alterations, which result in greater bone frailty and in an increased fracture risk. Many drugs have been studied to determine whether they prevent bone loss or reduce the incidence of additional fractures in patients with established osteoporosis. Primary prevention of osteoporosis rests on regular exercising and adequate intake of dietary calcium. For secondary prevention in women undergoing menopause, replacement estrogen therapy given for at least ten years is associated with substantial reductions in fractures of the radius, hip, and spine. Other drugs capable of arresting postmenopausal bone loss include parenteral, nasal or rectal calcitonin and diphosphonates. However, the long-term safety of the latter requires further evaluation. Current studies are evaluating new molecules with potential preventive efficacy, such as ipriflavone. There is no general consensus about the efficacy of treatments for established osteoporosis with fractures. To date, no controlled studies have demonstrated a reduction in the incidence of further fractures in patients given calcium alone. Studies of hydroxylated vitamin D derivatives have been disappointing, although daily administration of vitamin D3 in combination with calcium significantly reduced the incidence of nonvertebral fractures in a population of elderly institutionalized subjects. Plausible explanations for this effect include increased vitamin D levels and reduced parathyroid levels in the bloodstream. Parenteral or nasal calcitonin stabilizes or increases bone mineral content in both cancellous and cortical bone. This effect is especially marked in high-turn-over patients. Several lines of evidence suggest that calcitonin therapy has a protective effect against vertebral and hip fractures. In patients with osteoporosis, oral or intravenous diphosphonates are associated with a significant increase in cancellous bone mass with no loss of cortical bone. Etidronate may be especially beneficial in severe osteoporosis with marked loss of bone and multiple vertebral crush fractures. Fluoride stimulates the growth and synthetic activity of osteoblasts. Accurate information is needed on the optimal dosage of fluoride, on the effects of fluoride on the appendicular skeleton, and, above all, on the biomechanical properties of the bone produced under fluoride therapy. In addition to these commercially available drugs, several other agents are at various stages of the development process.(ABSTRACT TRUNCATED AT 400 WORDS) [less ▲]

Detailed reference viewed: 11 (1 ULg)
Full Text
Peer Reviewed
See detailA 5-Year Controlled Randomized Study of Prevention of Postmenopausal Trabecular Bone Loss with Nasal Salmon Calcitonin and Calcium
Reginster, Jean-Yves ULg; Meurmans, L.; Deroisy, Rita ULg et al

in European Journal of Clinical Investigation (1994), 24(8), 565-9

The aim of this paper was to evaluate the long-term (5 years) efficacy of nasal salmon calcitonin in prevention of trabecular postmenopausal bone loss, which was a follow-up of a previously published ... [more ▼]

The aim of this paper was to evaluate the long-term (5 years) efficacy of nasal salmon calcitonin in prevention of trabecular postmenopausal bone loss, which was a follow-up of a previously published study (3 years); a randomized, controlled group comparison. One hundred healthy postmenopausal women were randomly chosen from those (186) having completed the 3 year protocol. The 100 women were allocated to an additional 2 year period (total of 5 years) of treatment with either 500 mg d-1, 5 days week-1 of calcium or the same amount of calcium plus 50 IU d-1, 5 days per week of nasal salmon calcitonin, 87 (87%) women complied with the protocol throughout. The main outcome measures were the bone mineral density of the lumbar spine (1-BMD) (DPA) and biochemical parameters reflecting bone turnover (serum alkaline phosphatases, urinary calcium/creatinine and hydroxyproline/creatinine ratios). The women receiving calcium alone presented a significant decrease in 1-BMD after 6 months [-1.6 (0.5)%] [mean(SEM)] (P < 0.01) and this decrease remained significant after 36 months [-6.1(0.8)%] (P < 0.01) and until the end of the trial [-6.6(1.0)% at t60] (P < 0.01). In women receiving calcium and calcitonin, 1-BMD significantly increased after 36 months [+2(0.7%] (P < 0.01) and 42 months [+2.5(0.7)%] (P < 0.01 and was unchanged at the other times of investigation [+1.1 (1.1)% at t60] (NS). The evolution of BMD in the two groups was highly significantly different (P < 0.001) since the sixth month of the study and remained so until the end of the study.(ABSTRACT TRUNCATED AT 250 WORDS) [less ▲]

Detailed reference viewed: 6 (1 ULg)
Full Text
Peer Reviewed
See detailEfficacy and Tolerability of a New Formulation of Oral Tiludronate (Tablet) in the Treatment of Paget's Disease of Bone
Reginster, Jean-Yves ULg; Treves, R.; Renier, J. C. et al

in Journal of Bone and Mineral Research : The Official Journal of the American Society for Bone and Mineral Research (1994), 9(5), 615-9

We sought to assess efficacy and safety of a new oral formulation (tablet) of tiludronate in Paget's disease of bone. We studied 128 patients with Paget's disease in an open-label uncontrolled trial ... [more ▼]

We sought to assess efficacy and safety of a new oral formulation (tablet) of tiludronate in Paget's disease of bone. We studied 128 patients with Paget's disease in an open-label uncontrolled trial. Patients received a daily dose of 400 mg oral tiludronate (two tablets). Treatment was for 6 months. Serum alkaline phosphatase activity (SAP) and fasting urinary excretion of hydroxyproline/creatine (OH/Cr) were measured every 3 months, as were biochemical parameters reflecting renal, hepatic, and hematologic functions. Analgesic efficacy was self-evaluated from a visual analog scale (VAS). Statistical analysis revealed a significant reduction from baseline in SAP and OH/Cr levels, as well as VAS scores. In the whole population with evaluation under treatment, there was a reduction in initial SAP activity after 3 months (47.2 +/- 2.2%, mean +/- SEM) and 6 months (58.3 +/- 2.3%). In the population with SAP levels above twice the upper limit at inclusion and with evaluation at month 3 and month 6 (n = 96), the reduction in SAP levels was 49.3 +/- 2.4% after 3 months and of 59.5 +/- 2.6% after 6 months (ANOVA time effect, p = 0.0001). Aside from mild gastrointestinal disturbances, as experienced with other oral bisphosphonates, clinical tolerance was good. Exhaustive biochemical investigation failed to reveal significant toxicity of tiludronate tablets at the dose of 400 mg/day. The dose of 400 mg daily of this new formulation appears to be a satisfactory tiludronate regimen for the treatment of Paget's disease of bone. [less ▲]

Detailed reference viewed: 3 (1 ULg)
Peer Reviewed
See detailGonadotropin Releasing Hormone Inhibitory Autofeedback by Subproducts Antagonist at N-Methyl-D-Aspartate Receptors: A Model of Autocrine Regulation of Peptide Secretion
Bourguignon, Jean-Pierre ULg; Alvarez Gonzalez, Maria-Luz ULg; Gerard, Arlette ULg et al

in Endocrinology (1994), 134(3), 1589-92

The secretion of Gonadotropin-releasing Hormone (GnRH) involves activation of N-methyl-D-aspartate (NMDA) receptors. Here, we show that pulsatile GnRH secretion from hypothalamic explants is suppressed by ... [more ▼]

The secretion of Gonadotropin-releasing Hormone (GnRH) involves activation of N-methyl-D-aspartate (NMDA) receptors. Here, we show that pulsatile GnRH secretion from hypothalamic explants is suppressed by 1-5GnRH, an endogenous breakdown product of GnRH, while 2-10GnRH has no effect. GnRH secretion evoked by NMDA is selectively inhibited by 1-5GnRH and this effect is similar to that of AP-5, a competitive antagonist at NMDA receptors. In addition, 1-5GnRH accounts for a dose-related inhibition of tritiated glutamate binding to hypothalamic membrane preparations. Using GnRH secretion as a model of NMDA-receptor controlled system, the effect of different peptides has been studied. Growth Hormone Releasing Factor (GRF), Insulin-like Growth Factor-I (IGF-I) and Proinsulin result in inhibition of GnRH secretion. Bioactive subproducts of those peptides (1-29GRF, 4-701GF-I and insulin) do not show any effect, suggesting that their classical receptors are not involved. In contrast, GnRH secretion is inhibited by other subproducts (1-37GRF, 1-31GF-I and C-peptide) all terminating in a glutamate residue. These subproducts selectively suppress the NMDA-evoked secretion of GnRH. Protease inhibitors prevent the inhibitory effects of IGF-I on GnRH secretion. This, breakdown products of different peptide hormones are possible endogenous antagonists at NMDA receptors. This effect could account for an autocrine or paracrine limitation of NMDA-receptor-mediated secretion of peptides. [less ▲]

Detailed reference viewed: 25 (4 ULg)
Full Text
Peer Reviewed
See detailLong-Term (3 Years) Prevention of Trabecular Postmenopausal Bone Loss with Low-Dose Intermittent Nasal Salmon Calcitonin
Reginster, Jean-Yves ULg; Denis, D.; Deroisy, Rita ULg et al

in Journal of Bone and Mineral Research : The Official Journal of the American Society for Bone and Mineral Research (1994), 9(1), 69-73

The long-term effect of intermittent low-dose nasal salmon calcitonin on trabecular early postmenopausal bone loss was assessed as follow-up to a previously published study. Randomized controlled group ... [more ▼]

The long-term effect of intermittent low-dose nasal salmon calcitonin on trabecular early postmenopausal bone loss was assessed as follow-up to a previously published study. Randomized controlled group comparison was made of 287 healthy women with 6-36 months of natural menopause and no treatment interfering with calcium metabolism at an outpatient clinic for research in bone and cartilage metabolism. The 287 women were randomly allocated to 3 years of treatment with either 500 mg/day, 5 days/week of calcium or the same amount of calcium plus 50 IU/day, 5 days per week of nasal salmon calcitonin. A total of 186 women complied with the study protocol throughout. The main outcome measures were bone mineral density of the lumbar spine (DPA) and biochemical parameters reflecting bone turnover (serum alkaline phosphatases, urinary calcium/creatinine, and hydroxyproline/creatinine ratio). The average changes in bone mineral density after 36 months showed a positive (p < 0.05) outcome (1.8 +/- 5.7%; mean +/- SD) in the group treated with salmon calcitonin and calcium and a significant (p < 0.01) loss (-5.8 +/- 4.8%) in patients receiving calcium alone. The difference between the evolution of the two groups was significantly (p < 0.01) different after 6 months of treatment and remained so until the end of the study. No significant changes were recorded in biochemical parameters reflecting bone turnover. As previously shown during a 1 year follow-up, nasal salmon calcitonin given at low dose and intermittently, in association with calcium, can counteract trabecular postmenopausal bone loss. [less ▲]

Detailed reference viewed: 8 (1 ULg)
Peer Reviewed
See detailAcute biochemical variations induced by four different calcium salts in healthy male volunteers
Reginster, Jean-Yves ULg; Denis, D; Bartsch, V et al

in Equilibre (1994), 19

Detailed reference viewed: 15 (2 ULg)