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 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The function of the adenohypophyseal-gonadal axis in haemodialyzed male patients is modified: the serum testosterone level is low, and the gonadotropin levels are increased. The pathogenetic role of secondary hyperparathyroidism in this disorder has not previously been defined. The area under the curve (AUC) and the secretion kinetics of testosterone, luteinizing hormone (LH), and follicle-stimulating hormone after administration of LH-releasing hormone were examined in 7 dialyzed men with secondary hyperparathyroidism (mean age 36.2, range 20-47 years) before and 3 and 6 months after parathyroidectomy (PTX). The operation was successful in all 7 patients, as intact parathyroid hormone declined markedly during both postoperative periods as compared with the values before PTX: 81 +/- (SEM) 34 and 138 +/- 57 ng/1 versus 965 +/- 116 ng/l (p < 0.01 and p < 0.0l). The testosterone AUC prior to PTX (63 +/- 115 nmol/l x min) and 3 months (-4 +/- 36 nmol/l x min) and 6 months after PTX (-62 +/- 69) did not differ significantly, as was the case with LH AUC (1,110 +/- 223 and 1,214 +/- 331 and 1,020 +/- 314 U/l x min, respectively) and follicle-stimulating hormone AUC (525 +/- 334 and 634 +/- 347 and 533 +/- 264 U/l x min, respectively). The secretion kinetics of all three hormones was atypical as compared with healthy men of similar age, but it did not change after PTX. There were no correlations between the sexual indicators and parathyroid hormone, 1,25(OH)2D3, calcium, or phosphate during the individual periods. These findings indicate that secondary hyperparathyroidism is probably not involved in the dysfunction of the adenohypophyseal-gonadal axis in dialyzed men.
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PMID:Adenohypophyseal-gonadal dysfunction in male haemodialyzed patients before and after subtotal parathyroidectomy. 893 77

This study was designed to compare both the effectiveness and safety of two low-dose gonadotrophin regimens (step-up versus sequential step-up and step-down) for ovulation induction in polycystic ovarian syndrome (PCOS) patients. In all, 56 infertile clomiphene citrate-resistant PCOS patients were included in this prospective randomized study. A total of 38 cycles were conducted with a classic step-up protocol, whereas for 35 cycles the follicle-stimulating hormone (FSH) threshold dose was reduced by half when the leading follicle reached 14 mm in diameter (sequential protocol). Serum oestradiol, progesterone and luteinizing hormone concentrations and follicular growth rate were evaluated during the cycle. At the time of human chorionic gonadotrophin administration, cycles treated with sequential protocol exhibited significantly lower oestradiol concentrations [434 +/- 45 versus 593 +/- 67 pg/ml (mean +/- SEM)] and the number of medium-sized (14-15 mm) follicles was significantly reduced (0.3 +/- 0.1 versus 0.8 +/- 0.2) compared with cycles treated with the classic step-up protocol. Moreover, in these cycles serum luteal oestradiol concentrations were decreased significantly (350 +/- 77 versus 657 +/- 104 pg/ ml) compared with the classic step-up protocol. A sequential step-up and step-down protocol seems to be a safe and effective regimen for ovulation induction in PCOS patients. Decreasing the FSH dose following step-up follicular selection may be an alternative method to avoid multifollicular development.
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PMID:Sequential step-up and step-down dose regimen: an alternative method for ovulation induction with follicle-stimulating hormone in polycystic ovarian syndrome. 902 54

Long-term therapy with recombinant human erythropoietin (rhEPO) in uremic male patients undergoing hemodialysis has been followed by an increase in plasma levels of testosterone and a decrease in baseline levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The aim of the present study was to assess the effect of acutely administered rhEPO on FSH and LH responses to gonadotropin-releasing hormone (GnRH) in a group of uremic patients undergoing continuous ambulatory peritoneal dialysis (CAPD). Sixteen clinically stable male patients (age, mean+/-SEM, 45.3+/-3.9 years) with chronic renal insufficiency and 12 healthy volunteers with a normal renal function, matched for age and body mass index, were studied. All patients were on CAPD therapy for at least 3 months, and none of them received rhEPO therapy. Patients were moderately anemic (hemoglobin 11.0+/-0.3 g/dl) and showed testosterone levels significantly lower than those found in control subjects (3.47+/-0.37 vs. 6.91+/-0.49 ng/ml, p < 0.001). Each subject was tested with GnRH (100 microg i.v. as bolus) and with GnRH plus rhEPO (40 U/kg at a constant infusion rate for 30 min, starting 15 min before GnRH injection) on different days. Blood samples for FSH and LH were obtained between -30 and 120 min. In uremic patients the baseline FSH levels were higher than those found in control subjects (18.88+/-5.41 vs. 6.41+/-1.10 mU/ml, p < 0.05). After GnRH administration FSH values reached a maximum of 25.50+/-6.19 mU/ml in patients and of 12.50+/-2.02 mU/ml in controls (p < 0.05). rhEPO infusion produced a significant (p < 0.01) decrease in the area above the baseline value of FSH in uremic patients, with no other change in FSH responses to GnRH both in patients and controls. Baseline LH concentrations were significantly higher in patients than in controls (15.56+/-3.41 vs. 2.58+/-0.36 mU/ml, p < 0.001). LH peak and area under the curve of LH secretion after GnRH were significantly higher in patients than in controls (45.25+/-6.28 vs. 26.83+/-4.62 mU/ml, p < 0.05, and 77.02+/-11.30 vs. 34.40+/-5.22 mU x h/ml, p < 0.005, respectively). When GnRH was injected during the rhEPO infusion, a significant (p < 0.02) reduction in LH concentrations at 60, 90, and 120 min was found in uremic patients. Accordingly, the LH area under the curve was significantly reduced in patients (65.99+/-11.44 mU x h/ml, p < 0.05). rhEPO had no effect on GnRH-induced LH release in control subjects. These results suggest that acute rhEPO administration might reduce the exaggerated LH response to GnRH stimulation found in uremic male patients on CAPD.
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PMID:Effects of erythropoietin on gonadotropin responses to gonadotropin-releasing hormone in uremic patients. 934 83

The aim of the present prospective longitudinal study was to investigate the hormonal response in overtrained athletes at rest and during exercise consisting of a short-term exhaustive endurance test on a cycle ergometer at an intensity 10% above the individual anaerobic threshold. Over a period of 19+/-1 months, 17 male endurance athletes (cyclists and triathletes; age 23.4+/-1.6 yr; VO2max. 61.2+/-1.8 mL x min(-1) x kg(-1); means+/-SEM) were examined five times on two separate days under standardized conditions. Short-term overtraining states (OT, N=15) were primarily induced by an increase of frequency of high-intensive bouts of exercise or competitions without increase of the total amount of training. OT was compared with normal training states intraindividually (NS, N=62). During OT, the time to exhaustion of the exercise test was significantly decreased by 27% on average. At rest and during exercise, the concentrations in plasma and the nocturnal excretion in urine of free epinephrine and norepinephrine were not significantly changed during OT. At physical rest, the concentrations of (free) testosterone, cortisol, luteinizing hormone, follicle-stimulating hormone, adrenocorticotropic hormone, growth hormone, and insulin during OT were comparable with those during NS. A significantly (P < 0.025) lower maximal exercise-induced increase of the adrenocorticotropic hormone and growth hormone, as well as a trend for a decrease of cortisol (P=0.060) and insulin (P=0.036), was measured. The response of free catecholamines as well as the ergometric performance of an all-out 30-s test was unchanged. Serum urea, uric acid, ferritin, and activity of creatine kinase showed no differences between conditions. In conclusion, the results confirm the hypothesis of a hypothalamo-pituitary dysregulation during OT expressed by an impaired response of pituitary hormones to exhaustive short-endurance exercise.
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PMID:Impaired pituitary hormonal response to exhaustive exercise in overtrained endurance athletes. 952 87

The advantages of quantitative ultramorphological (QUM) sperm analysis in the diagnosis and treatment of male infertility are presented. QUM methodology is based on three elements: (1) complementary SEM and TEM observations of 7 sperm cell subcellular organelles: acrosome, postacrosomal lamina, nucleus, neck, axoneme, mitochondrial sheath, and outer dense fibers; (2) systematic classification of the specific ultramorphological malformations into 4 pathological and the normal categories, which indicate the morphological state of each subcellular organelle; and (3) comparison between well-defined reference groups with opposite fertility status or treatment conditions. QUM analysis has enabled the establishment of two indices that optimally express the in vivo and in vitro male fertility potential: The Natural Fertility Index (NFI), which allowed an accurate prediction (97% sensitivity and 90% specificity) of 80% of the naturally fertile and suspected infertile male patients, and the in vitro fertilization (IVF) score, which enabled prediction of 76% of the nonfertilizing and 90% of the fertilizing IVF groups. Validation tests confirmed these data. QUM also enabled assessment of ultramorphological indications for varicocele and radiation exposure: Both male factor etiologies indicated a persistent effect on the natural fertility potential, as expressed by structural changes in the nucleus. Varicocele was found to cause defects in the sperm head organelles related to early spermatid development, whereas ionizing radiation resulted in amorphous head shape. Criteria for specific non-in vitro therapeutic interventions such as varicocelectomy, follicle-stimulating hormone (FSH) administration, and acupuncture treatment were established. A varicocele index, which enabled the correct classification of 79 and 89% of the patients pre- and post-high ligation, respectively, was suggested to be a good indicator for varicocele which affects the fertility potential. Males exhibiting idiopathic impairment of sperm acrosome and nucleus were found to be potential responders to FSH treatment, whereas patients exhibiting low sperm activity proved to be good candidates for acupuncture treatment. Indications for selecting the optimal appropriate assisted reproduction technique (ART) procedure were found: Patients with a low Natural Fertility Index should be recommended for ART. A first choice ART selection should be performed according to an ART index based on the ultramorphological examination of the tail axoneme. The above index enabled correct prediction of 78% of the patients who achieved pregnancy following conventional ART (intrauterine insemination or IVF) and 74% of those whose wives conceived only following intracytoplasmic sperm injection. QUM sperm analysis is clinically informative, nontraumatic, and in the long run also cost-effective. This analysis should be performed when the male infertility factor cannot be clearly diagnosed by routine tests and prior to the first ART trial.
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PMID:Quantitative ultramorphological (QUM) analysis of human sperm: diagnosis and management of male infertility. 1040 47

We investigated the participation of neuropeptide Y-Y1 receptors within the medial preoptic area in luteinizing hormone, follicle-stimulating hormone and prolactin release. Four bilateral microinjections of sense (control) or antisense 18-base oligonucleotides of messenger ribonucleic acid (mRNA) (250 ng) corresponding to the NH2-terminus of the neuropeptide Y1 receptor were performed at 12-h intervals for two days into the medial preoptic area of ovariectomized Wistar rats (N = 16), weighing 180 to 200 g, treated with estrogen (50 microg) and progesterone (25 mg) two days before the experiments between 8.00 and 10:00 a.m. Blockade of Y1 receptor synthesis in the medial preoptic area by the antisense mRNA did not change plasma luteinizing hormone or follicle-stimulating hormone but did increase prolactin from 19.6 +/- 5.9 ng/ml in the sense group to 52.9 +/- 9.6 ng/ml in the antisense group. The plasma hormones were measured by radioimmunoassay and the values are reported as mean +/- SEM. These data suggest that endogenous neuropeptide Y in the medial preoptic area has an inhibitory action on prolactin secretion through Y1 receptors.
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PMID:Antisense mRNA for NPY-Y1 receptor in the medial preoptic area increases prolactin secretion. 1046 94

Two breeding trials were done to determine the effect of pyriform-shaped bovine spermatozoa on fertility. In breeding trial (1), heifers were superstimulated by injecting follicle-stimulating hormone (FSH) and randomly allotted to an affected Bull A (n = 21) or a Control Bull, C (n = 18). Semen from Bull A contained 85% pyriform spermatozoa while that from the Control Bull C contained 91% normal sperm and 2% pyriform spermatozoa. Fertilization rate was lower (P = 0.01) for Bull A (total of 63 ova/embryos; 68.5%) than for the Control Bull, C (total of 81 ova/embryos; 84.4%). In breeding trial (2), 37 oestrus-synchronized heifers were randomly allotted to Bull A (n = 19) or Bull C (n = 18). Pregnancy rates at Day 60 (37% and 61% for Bulls A and C, respectively; P = 0.22) and rate of embryo/fetal loss between Days 22 and 60 of pregnancy (23% and 8% for Bulls A and C, respectively; P = 0.55) were not different. In vitro experiments involving the same Bull A and another Control Bull, B, were designed to explain the mechanism of infertility caused by pyriform sperm. The mean (+/- SEM) number of sperm bound to the zona pellucida was lower (P < 0.05) for Bull A (24.6+/-1.2) than for the Control Bull, B (46.6+/-1.9) and the percentage of zonae penetrated by sperm from Bull A (56.0%) and Bull B (82.8%) was also different (P < 0.05). The percentage of pyriform sperm from Bull A bound to (53%), and penetrating (49%) the zona pellucida was lower (P < 0.05) than that in the inseminate (85%). Although fertilization rates (64.1% and 72.8%) were not different (P = 0.5), cleavage rates (48.2% vs. 74.1%) and morula production rates (24.8% vs. 37.7%) were less (P < 0.05) for Bull A than for Bull B, respectively. In summary, pyriform sperm had reduced capability to bind to and penetrate the zona pellucida, and zygotes (resulting from the fertilization of oocytes by pyriform sperm) appeared to have a reduced ability to initiate cleavage.
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PMID:An investigation of the fertilizing characteristics of pyriform-shaped bovine spermatozoa. 1056 38

A total of 607 calving intervals on 99 Ayrshire cows with parities from 1 to 10 and belonging to one dairy herd at Iringa in the southern highlands of Tanzania were analysed to study the effect of parity and season or month of calving on the subsequent calving interval. In addition, 22 calving intervals incorporating a superovulatory cycle were compared with those of 52 controls that had calved around the same period. The average (mean +/- SEM) age at first calving was 985 +/- 16 days. The effect of parity on calving interval was highly significant (p < 0.001). Cows that calved in December, at the beginning of the rainy season, exhibited the shortest calving interval (404 +/- 13), while those that calved in September/October, in the dry season, exhibited the longest average calving interval (466 +/- 20 days), although this difference was not significant. Prior treatment with follicle-stimulating hormone to induce superovulation, significantly lengthened the average calving interval (579 +/- 28 vs 457 +/- 15 days; p < 0.001). It was concluded that both parity and FSH treatment affected the calving interval. However, season (rainy vs dry) or month of calving did not influence this interval.
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PMID:Effect of parity, season and FSH treatment on the calving interval of Ayrshire cows in the tropics. 1090 92

Hypothyroidism has been shown to be associated with a reduction in serum testosterone level in males. This reduction in testosterone is reversible by thyroxine replacement therapy. However, to the best of our knowledge, it is not yet known, whether a similar reduction in serum testosterone level is observed in subclinically hypothyroid males [thyroid-stimulating hormone (TSH) < 10 mIU/L] in whom the benefits of thyroxine replacement therapy are still controversial. Our goal was to investigate the putative connections between subclinical hypothyroidism and the circulating levels of gonadotrophins and gonadal steroids in males (mean age +/- SEM, 34.67 +/- 1.52 years; ranging from 20 to 54 years). The serum samples from patients showing normal euthyroid and subclinical hypothyroid profiles (TSH < 10 mIU/L) were further analysed for the levels of luteinizing hormone, follicle-stimulating hormone, prolactin, testosterone, sex hormone-binding globulin, progesterone and oestradiol. Subclinical hypothyroidism was associated with a decrease in the levels of serum testosterone and its precursor progesterone. The data suggest that serum testosterone declines because of the non-availability of its precursor progesterone. The level of oestradiol was similar in both the groups, suggesting a greater conversion rate of testosterone to oestradiol in subclinically hypothyroid males, in order to maintain the oestradiol levels. Prolactin levels were slightly but significantly increased in subclinical hypothyroidism. To the best of our information this is a novel report, which shows a direct association between subclinical hypothyroidism and hypoandrogenaemia. Testosterone deficiency and its symptoms should be kept in view while managing subclinical hypothyroidism in male patients. Further studies are needed in order to reveal the physiological and molecular mechanisms leading to hypoandrogenaemia in subclinical hypothyroidism (TSH < 10 mIU/L).
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PMID:Hypoandrogenaemia is associated with subclinical hypothyroidism in men. 1687 21

Liver cirrhosis, a highly prevalent chronic disease, is frequently associated with endocrine dysfunctions, notably in the gonadal axis. We evaluated lactotroph population by immunohistochemistry, gonadotropins and prolactin by immunoradiometric assay and testosterone and estradiol by radioimmunoassay in adult male Wistar rats with cirrhosis induced by carbon tetrachloride. No significant difference in mean +/- SEM percentages of lactotrophs was found between cirrhotic animals and controls (N = 12, mean 18.95 +/- 1.29%). Although there was no significant difference between groups in mean serum levels of prolactin (control: 19.2 +/- 4 ng/mL), luteinizing hormone (control: 1.58 +/- 0.43 ng/mL), follicle-stimulating hormone (control: 19.11 +/- 2.28 ng/mL), estradiol (control: 14.65 +/- 3.22 pg/mL), and total testosterone (control: 138.41 +/- 20.07 ng/dL), 5 of the cirrhotic animals presented a hormonal profile consistent with hypogonadism, all of them pointing to a central origin of this dysfunction. Four of these animals presented high levels of estradiol and/or prolactin, with a significant correlation between these two hormones in both groups (r = 0.54; P = 0.013). It was possible to detect the presence of central hypogonadism in this model of cirrhotic animals. The hyperestrogenemia and hyperprolactinemia found in some hypogonadal animals suggest a role in the genesis of hypogonadism, and in the present study they were not associated with lactotroph hyperplasia.
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PMID:Male gonadal function, prolactin secretion and lactotroph population in an experimental model of cirrhosis. 1771 59


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