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J Schoemaker

Publications and source records attributed to J Schoemaker.

At least 91 records · Page 5Linked to original sources
PubMed1993

Dysfunction of monocytes and dendritic cells in patients with premature ovarian failure.

PROBLEM: Due to the presence of ovarian antibodies it has been suggested that premature ovarian failure (POF) belongs to the autoimmune endocrinopathies. Monocytes and the monocyte-derived dendritic cells play a prominent role in the initial stages of endocrine autoimmune reactions: the accumulation of monocytes/dendritic cells and the clustering of dendritic cells in endocrine organs is one of the first phenomena of an autoimmune endocrinopathy. METHOD: This report describes a study on (1) the chemotactic responsiveness of blood monocytes, and (2) the cluster capability of blood dendritic cells in POF patients. The monocyte chemotaxis was determined using the cell's capability to polarize (changes in shape determined by light microscopy) under the influence of the chemoattractant, N-formyl-methionyl-leucyl-phenylalanine (fMLP). The cluster capability of dendritic cells was tested by allowing the dendritic cells to form aggregates with allogenic lymphocytes in vitro. RESULTS: The blood monocytes of 46% of a total of 28 POF patients showed a decreased fMLP induced monocyte polarization in comparison to healthy control values. None of the young female controls (N = 28) and postmenopausal women (N = 17), showed such a defective monocyte polarization. The blood dendritic cells of 36% of the POF patients showed a decreased cluster capability. Defects in monocyte polarization and dendritic cell clustering were not affected by therapies aimed at changes in the estrogen levels or gonadotropin levels of the patients [using estrogen substitution therapy, gonadotropin-releasing hormone (GnRH) analog, follicle-stimulating hormone (FSH)]. CONCLUSIONS: A redistribution of active monocytes and of active dendritic cells from the peripheral blood to the ovaries may be the cause of the described abnormalities. Since similar abnormalities in monocyte function and dendritic cell function have been described in Graves' disease and type I diabetes, the data strengthen the view that POF is one of the endocrine autoimmune diseases.

Adult↗
PubMed1993

Pulsatile luteinizing hormone patterns in long term oral contraceptive users.

Oral contraceptives (OC) inhibit folliculogenesis by a central suppressive action on the release of gonadotropins. To characterize the nature of these central effects, we studied 40 long term OC users on 3 different OCs: two monophasic preparations with 30 micrograms ethinyl estradiol and 150 micrograms l-norgestrel (group 1; n = 15), 150 micrograms desogestrel (group 2; n = 10), and a triphasic formulation containing 30-40 micrograms ethinyl estradiol and 50, 75, and 125 micrograms l-norgestrel (group 3; n = 15). Blood sampling at 10-min intervals during 6-h periods was performed at different moments in the pill cycle. Thirteen healthy volunteers with regular ovulatory cycles served as normal controls. FSH and LH were measured by a sensitive immunoradiometric assay. Pulsatile LH release was observed in all OC users. Mean serum LH and FSH levels, number of LH pulses per 6 h, and the amplitude of LH pulses on day 1 of the pill cycle did not differ from early follicular phase control values. FSH levels were rapidly suppressed from day 2 onward in all three groups, whereas LH levels progressively declined in groups 1 and 2 from day 8 onward. In group 3, however, LH levels were only significantly suppressed after day 13. The number of LH pulses per 6 h decreased in all groups starting on day 2, whereas the amplitude of LH pulses increased. A substantial percentage of LH pulses observed in OC users after day 1 were of low amplitude (< 0.75 IU/L). From these results, we conclude that 1) pulsatile release of LH is maintained during OC use; 2) FSH levels are suppressed equally early and equally effective by all OCs studied; 3) during OC use, the number of LH pulses per 6 h is reduced; 4) modulation of LH pulse amplitudes, and subsequently of serum LH levels, is mainly mediated by a dose- and time-dependent effect of the gestagenic component of the OC; and 5) after the 7-day pill-free interval, a normal early follicular phase pulse pattern is found, even in long term OC users, suggesting that in this period, most of the steroidogenic feedback effects wear off.

Adult↗
PubMed1993

Pulsatile luteinizing hormone secretion during the first and the fourth cycle on two different oral contraceptives containing gestodene.

Oral contraceptives inhibit ovarian follicular growth by suppressing the release of gonadotropins from the pituitary. We studied basal and gonadotropin-releasing hormone-stimulated gonadotropin release, as well as pulsatile luteinizing hormone (LH) secretion, in ten healthy volunteers who had not used oral contraceptives before. Subjects received either a monophasic preparation containing 30 micrograms of ethinylestradiol and 75 micrograms of gestodene (group 1) or a triphasic formulation containing 30-40 micrograms of ethinylestradiol and 50, 70 and 100 micrograms of gestodene (group 2). Blood sampling at 10-min intervals during 6-h periods was performed on days 1, 8, 15 and 21 of both the first and fourth pill cycle. Thirteen healthy volunteers with regular ovulatory cycles served as normal controls. Both LH and follicle-stimulating hormone (FSH) were measured by a sensitive immunoradiometric assay. Pulsatile LH secretion was observed in all oral contraceptive users. Mean serum LH and FSH levels, number of pulses/6 h and the amplitude of LH pulses on day 1 in both the first and fourth pill cycle did not differ from early follicular phase controls in both groups. The FSH levels were suppressed rapidly in both groups, even in first cycles, while LH serum levels progressively declined in all cycles studied. In both groups, amplitudes of LH pulses decreased from day 8 onwards, with a substantial number of low-amplitude pulses (< 0.75 U/l) interspersed between large-amplitude pulses. On day 1 of the fourth pill cycle a significant number of pulses were of low amplitude.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

The effects of levonorgestrel, desogestrel and gestodene on the pulsatile release of luteinizing hormone in oral contraceptive users.

The dynamics of luteinizing hormone (LH) and follicle stimulating hormone (FSH) release were investigated in 60 long-term oral contraceptive (OC) users. Five different types of OC, all containing the same amount of estrogens were studied: three monophasic preparations containing levonorgestrel, desogestrel and gestodene, respectively, and two triphasic formulations, containing levonorgestrel or gestodene. Thirteen healthy, normally cycling volunteers served as controls. Blood sampling was performed at 10-min intervals during a 6-h period to determine the pulsatile release of LH. LH and FSH were measured using a sensitive immunoradiometric assay. Pulse patterns were classified on the basis of the overall LH level, as well as on the character of the LH pulses, according to both frequency and amplitude characteristics. Pulsatile LH release was maintained during OC use. After the 7-day pill-free interval, FSH levels as well as the LH pulse patterns were comparable to those of early follicular-phase controls. FSH levels and FSH release in response to a gonadotropin releasing hormone (GnRH) challenge were profoundly suppressed in all OC users, as early as day 8 of the pill cycle. LH release during the pill cycle was characterized by either a low frequency (median 1 pulse/6 h), high amplitude (median 2.5 IU/l) pulse pattern or by a pattern of low-amplitude pulses (median 0.2 IU/l) and low basal LH levels (median 0.2 IU/l). The distribution of these pulse patterns showed marked differences between different OC preparations and depended on both the type and dose regimen of the gestagenic component of the OC.

Adult↗
PubMed1993

Effects of the opioid antagonist naltrexone-estrone azine on the luteinizing hormone-releasing hormone induced release of luteinizing hormone from the pituitary glands of ovariectomized rats.

The effects were studied of in vivo administration of the new opioid antagonist-estrogen hybrid, naltrexone-estrone azine (EH-NX), on subsequent luteinizing hormone-releasing hormone (LHRH)-stimulated luteinizing hormone (LH) release by the pituitary gland in vitro. It is well known that administration of estrogen exerts negative and positive effects on the pituitary LH response to LHRH, respectively after short-term and long-term treatment. Rats were injected subcutaneously with either 17 beta-estradiol-3-benzoate (EB), EH-NX or oil on days 18 and 19 (long-term treatment), and on day 21 (short-term treatment) following ovariectomy. Twenty minutes later the animals were killed and the pituitary glands were incubated in the presence of LHRH (1000 ng/ml) for 4 h. Whereas short-term treatment with EB on day 21 did not affect LH release in vitro, EH-NX significantly decreased the pituitary LH response to LHRH in oil pretreated rats. This inhibitory effect was partially blocked by the opioid antagonist naltrexone. After long-term EB or EH-NX, followed by short-term oil treatment, the pituitary LH response to LHRH was increased considerably, compared to the long-term oil controls. These observations demonstrate that the opioid antagonist estrogen hybrid EH-NX has estrogenic activity at the level of the pituitary gland. This hybridized drug is more effective in time than EB and an equimolar amount of EH (estrone hydrazone) to induce the negative estrogenic effect.

Animals↗
PubMed1992

Reliability of urinary LH testing for planning of endometrial biopsies.

A rapid urinary luteinizing hormone (LH) test was used to plan a late luteal phase endometrial biopsy from 20 women undergoing an infertility evaluation. Histologic dating was correlated with the day of urinary LH surge detection, the day of the basal body temperature (BBT) nadir, and the onset of the next menstrual period (NMP). From 17 interpretable specimens, histologic dating correlated well with the day of the biopsy as determined following a positive LH test detection (P = 0.079). No correlation was found following the BBT shift (P = 0.65), and it was significantly correlated with the NMP (P = 0.016). Moreover, the urinary LH test showed to be the best method to predict the onset of the NMP. These findings confirm urinary LH testing as a valuable adjunct in the investigation of luteal phase disorders.

Adult↗
PubMed1992

Estrogenic effects of the new opioid antagonist naltrexone-estrone azine on pituitary luteinizing hormone secretion in ovariectomized rats.

The effect of the new opioid antagonist naltrexone-estrone azine (EH-NX) on pituitary luteinizing hormone (LH) secretion in the ovariectomized rat was studied. EH-NX is a hybrid between the steroid component estrone and the opioid antagonist naltrexone (NX). It is a potent and long-acting opioid antagonist in vitro and in vivo, but its effect upon in vivo LH secretion has not been tested before. The aims of the study were to investigate whether, unlike naltrexone, EH-NX can stimulate LH secretion without the need of additional estrogen pretreatment and whether EH-NX has peripheral estrogenic effects upon the uterine weight, when administered chronically to long-term ovariectomized rats. Female rats were injected subcutaneously with EH-NX 21 days after ovariectomy. The effects of EH-NX injections on LH secretion were compared to the effects of NX and estrone hydrazone (EH) alone, or in combination, with or without estradiol-benzoate (EB) pretreatment. Inhibition of LH secretion and uterine proliferation were observed in rats treated chronically with EH-NX in dosages of 0.250 mg/kg bw and higher. These effects were similar to those caused by EH and EB. In short-term OVX rats EH-NX appeared to act faster than EH. In contrast to NX, no stimulatory effect on LH secretion was seen with EH-NX in EB primed OVX rats. These results surprisingly demonstrate that EH-NX behaves like an estrogen and not like an opioid antagonist. The unexpected pharmacological profile of this new drug may open up doors for several medical applications.

Animals↗
PubMed1992

Pulsatile luteinizing hormone secretion in hypothalamic amenorrhea, anorexia nervosa, and polycystic ovarian disease during naltrexone treatment.

OBJECTIVE: To determine if chronic treatment with the long-acting oral opioid antagonist naltrexone can increase luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion in women with secondary amenorrhea. DESIGN: Prospective. SETTING: Large reproductive endocrinology unit of an academic hospital. PATIENTS: Three groups of women with oligomenorrhea or amenorrhea: (1) hypothalamic amenorrhea; (2) anorexia nervosa; and (3) polycystic ovarian disease (PCOD). INTERVENTION: Naltrexone 50 mg every day for 4 days. MAIN OUTCOME MEASURES: Luteinizing hormone pulse pattern, frequency and amplitude, mean LH and FSH levels, measured by serial blood sampling over a 6-hour period before and after naltrexone. RESULTS: Naltrexone caused a significant increase (P less than 0.05) of the LH pulse frequency in patients with hypothalamic amenorrhea and in PCOD but not in anorexia nervosa. The mean levels of LH and FSH and LH pulse amplitudes were not significantly changed by naltrexone. The naltrexone nonresponders were underweight either because of simple weight loss or anorexia nervosa and had low levels of estradiol and an LH pulse pattern similar to the luteal one. CONCLUSION: The luteal LH pulse pattern in weight loss-related amenorrhea is caused by a nonopioid, undernutrition-linked factor.

Activity Cycles↗
PubMed1992

Reliability of home urinary LH tests for timing of insemination: a consumer's study.

In this study, intrauterine insemination (IUI) was timed either after the detection of a urinary luteinizing hormone (LH) surge at home by the patient (group A), or following a positive LH test as interpreted by the gynaecologist (group B). Afterwards, samples tested by the patient were retested by the gynaecologist and vice versa. The gynaecologist also rechecked his own findings and the results were correlated with ultrasound data and charts of basal body temperature. Forty-seven cycles were evaluated. The patient's and the gynaecologist's readings agreed (+/- 12 h) in 42 of the cases (89%), and in five cycles (11%) a difference greater than 24 h was found. The intra-observer variation in the gynaecologist's results was +/- 12 h in four cycles (8.5%). These findings suggest that the LH test can be used as a reliable home device for the prediction of pending ovulation and timing of IUI.

Adult↗
PubMed1992

Induction of multiple follicular growth by pulsatile gonadotrophin-releasing hormone (GnRH) treatment in women with normal cycles: the role of the route of administration.

In a prospective study, seven patients with normal menstrual cycles were treated with pulsatile gonadotrophin-releasing hormone. They received one cycle of intravenous (i.v.) therapy and one cycle of subcutaneous (s.c.) therapy. Another four volunteers with normal cycles were treated for one s.c. cycle only. Cycles were compared to each other and to the normal unstimulated cycles of 14 other volunteers. Multiple follicular development could be achieved using both the i.v. and the s.c. routes. However, the i.v. route showed significantly higher luteinizing hormone (LH) and luteal steroid levels. Comparing s.c. cycles to controls, significantly lower LH levels were observed, resulting in significantly lower steroid production if calculated per large follicle. We conclude that the i.v. route is superior to the s.c. route in inducing multiple follicular growth in women with normal cycles.

Adult↗
PubMed1992

Ovulation induction with a single-blind treatment regimen comparing naltrexone, placebo and clomiphene citrate in women with secondary amenorrhea.

Secondary amenorrhea is often associated with emotional stress, weight loss, eating disorders or polycystic ovary-like disease. Involvement of the endogenous opioids in the pathophysiology of hypothalamic amenorrhea, by inhibition of hypothalamic GnRH secretion, has been demonstrated in some cases. Chronic blockade of the endogenous opioids with the long-acting opioid antagonist naltrexone could result in increased gonadotropin secretion and ovulation induction in these cases. A single-blind ovulation induction protocol comparing naltrexone, placebo and clomiphene citrate was evaluated in eight patients with secondary amenorrhea. Naltrexone proved not to be more effective than placebo in our study. Only one patient ovulated on naltrexone, one on placebo and four on clomiphene citrate. The latter therapy caused a better endocrine response. In conclusion, although ovulation could be incidentally induced by naltrexone, this drug did not appear to be more successful than placebo and clomiphene citrate for ovulation induction in this population of patients.

Amenorrhea↗
PubMed1992

Pituitary and ovarian suppression after early follicular and mid-luteal administration of a LHRH agonist in a depot formulation: decapeptyl CR.

In order to study its effect on pituitary and ovarian function, a single dose of triptorelin depot (Decapeptyl CR, Ferring) was administered to 12 women in the early follicular (EF,n = 6) or mid-luteal phase (ML,n = 6) of a normal cycle. In all 12 women the initial pituitary and ovarian responses were similar. Luteinizing hormone (LH) and follicle stimulating hormone (FSH) rose to peak values within 48 h, and declined to hypogonadotropic levels within 2 weeks' time. Steroid levels showed a slight to marked rise after injection and fell to hypogonadal values within 1 week. LH suppression was maintained until the 8th week after the injection, while FSH levels rose to normal between the 3rd and 4th week. Estrogen secretion started to be restored in the course of the 7th and 8th week. Menses occurred between the 11th and 13th week after the injection of the drug. This study demonstrates the possibility of rapid induction of a hypogonadotropic and hypogonadal condition in regularly cycling women by administration of a single triptorelin depot. Suppression of pituitary and ovarian function appears to be continued until the 8th week after the injection.

Adult↗
PubMed1992

Effects of opioid antagonism with naltrexone on pulsatile luteinizing hormone secretion in women with hypothalamic amenorrhea in basal conditions and after discontinuation of treatment with pulsatile LHRH.

Although endogenous opioids seem to play an important role in the inhibition of luteinizing hormone releasing hormone (LHRH) secretion in women with hypothalamic amenorrhea, opioid antagonism does not always cause an increase of pituitary luteinizing hormone (LH) secretion. The effect of the long-acting oral opiate antagonist naltrexone on pulsatile LH secretion was studied in eight women with weight loss and exercise-related hypothalamic amenorrhea. LH pulse studies and LHRH tests were performed in basal conditions and after 4 days of naltrexone treatment, 50 mg q.d. Naltrexone caused a slight, but significant increase of LH pulse frequency. Six weeks later, a second experiment was performed. The response to naltrexone was studied after enhancement of the pituitary sensitivity. Patients were pretreated with pulsatile LHRH during 4 days, followed by naltrexone 50 mg q.d. during 4 days. An increased LH response to LHRH, but no response to naltrexone, were seen after discontinuation of pulsatile LHRH. It is concluded that the limited pituitary response to opioid antagonism, observed in weight loss-related forms of hypothalamic amenorrhea, is not caused by pituitary insensitivity to LHRH.

Adolescent↗
PubMed1991

CV 205-502, a new dopamine agonist, versus bromocriptine in the treatment of hyperprolactinaemia.

Forty-seven hyperprolactinaemic patients with serum prolactin (PRL) concentrations persistently above 1500 mU/l were treated with the new dopamine agonist CV 205-502 or bromocriptine in a prospective, randomized and double-blind fashion during a 24-week period. Two women had to be excluded because of poor compliance in the first month. Therefore 45 patients remained for evaluation. 81% of the patients in the CV 205-502 group and 70% of the patients in the bromocriptine group normalized their prolactin levels within the study period with a treatment dose as permitted in this protocol. In general serum prolactin normalized within 8 to 12 weeks of treatment. There were no differences between the two tested drugs regarding restoration of the menstrual cycle or disappearance of galactorrhoea. Both drugs gave rise to adverse reactions, especially during the initiation of therapy. However, the adverse reactions reported during CV 205-502 treatment were less severe and persistent than those attributed to bromocriptine. Patient acceptance of the new drug with regard to tolerability was judged by 90% of the women in that treatment group as very good or good, while 75% of those treated with bromocriptine evaluated its tolerability as very good or good. We conclude that CV 205-502 is highly effective in the treatment of hyperprolactinaemia with concomitant restoration of gonadal function and prevention of galactorrhoea. The tolerability of the drug seems better than of bromocriptine and therefore this drug is of value in the treatment of hyperprolactinaemic patients.

Adolescent↗
PubMed1991

Pregnancy rates after timed intercourse or intrauterine insemination after human menopausal gonadotropin stimulation of normal ovulatory cycles: a controlled study.

Forty-eight patients with male (n = 16) or idiopathic (n = 32) infertility were stimulated with human menopausal gonadotropin. Intrauterine insemination (IUI) or natural intercourse were performed after either human chorionic gonadotropin (hCG)-induced or spontaneous, urinary luteinizing hormone (LH) surge-monitored ovulation. A total of 148 cycles were analyzed. In 40 cycles treated with hCG-induced ovulation and IUI, 3 (7.5%) patients conceived, whereas 37 women accomplished natural intercourse after hCG-induced ovulation and 2 (5.5%) became pregnant. When inseminated after a spontaneous LH surge, 3 (8.8%) of 34 patients achieved a pregnancy; no conception occurred in 37 spontaneously ovulatory cycles combined with timed intercourse. Pregnancy rates did not substantially differ between the treatment modalities or between mono-ovulatory and polyovulatory cycles. The cycle characteristics between spontaneous ovulatory and hCG-induced cycles significantly did differ.

Chorionic Gonadotropin↗
PubMed1991

Life table analysis of fecundity in intravenously gonadotropin-releasing hormone-treated patients with normogonadotropic and hypogonadotropic amenorrhea.

The success of pulsatile intravenous (IV) gonadotropin-releasing hormone (GnRH) treatment in patients with normogonadotropic and hypogonadotropic amenorrhea was studied retrospectively using life table analysis. Two hundred forty-four ovulatory cycles in 48 normogonadotropic and hypogonadotropic patients were evaluated. The cumulative conception rate after 12 cycles was 93%, with a mean conception rate of 22.5% per cycle. Comparing cycles 1 to 6 with cycles 7 to 12, no significant difference in conception rate was observed. Subdivisions were made relative to the presence of additional infertility factors, history of weight loss, actual weight, estrogenic status, and primary versus secondary amenorrhea. The life table curves of patients either with or without other infertility factors were significantly different. No statistically significant differences were found in the other subdivisions. It is concluded that IV GnRH therapy is highly successful in patients with normogonadotropic and hypogonadotropic amenorrhea, especially if no other infertility factors are present.

Adult↗