bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Hypophysectomy on LH Receptor Binding and Leydig Cell Sensitivity and Responsiveness to hCG/LH in the Immature (30 Day) Rat
Authors: Purvis K. , Clausen O. P. F. , Torjesen P. A. , Hansson V. 
Published: May 2008

The sensitivity (dose of hormone eliciting half maximal response) and the magnitude of the maximal response of Leydig cell suspensions prepared from immature intact and immature eight day hypophysectomized rats to hCG and dibutyryl‐cyclic‐3'5‐adenosine monophosphate (dBC) were assessed in vitro in the presence or absence of the phosphodiesterase inhibitor, methylisobutyl‐xanthine (MIX). In separate studies LH/hCG binding to dispersed Leydig cells from intact and hypophysectomized rats of the same age was evaluated by Scatchard analysis and autoradiography.Hypophysectomy was associated with a 3–4 fold increase in the sensitivity of response, but an 80 % reduction in the maximum steroidogenic response to both hCG and dBC (when expressed per million 3β‐hydroxy‐steroid‐dehydrogenase (3β‐HSD) positive cells. Addition of MIX resulted in a greater increase in the sensitivity of response from intact Leydig cells than from cells from hypophysectomized rats, suggesting that hypophysectomy is associated with a decrease in the activity of the phosphodiesterase. Scatchard analysis of [125I]hLH binding to Leydig cells indicated no major decrease in the average number of LH/hCG receptors per cell after 8 days of hypophysectomy. Grain counts after autoradiography of the radiolabelled LH/hCG receptor confirmed this finding.
Testosterone and Dihydrotestosterone Concentrations in Spermatic Venous Blood of Azoospermic Subjects
Authors: Pazzagli M. , Giusti G. , Forti G. , Franchini M. , Scarselli G. F. , Guazzelli R. , Conti C. , Borrelli D. , Cicchi P. , Serio M. 
Published: May 2008

Testosterone and dihydrotestosterone were measured in spermatic venous blood of 37 azoospermic subjects. On the basis of testicular biopsy and vesiculodeferentography the patients were divided into three groups, i.e. subjects affected by azoospermia of obstructive origin with normal testicular histology, subjects with germinal cell arrest and those with Sertoli cell only syndrome (n = 6, n = 25 and n = 6 respectively).The mean values (± SE) of hormone concentrations in spermatic venous blood in the three groups were respectively 2312 ± 517 nM/l. 2292 ± 320 nM/l and 2006 ± 342 nM/l for testosterone and 28.8 ± 7.7 nM/l, 39.0 ± 5.9 nM/l and 41.9 ± 17.7 nM/l for dihydrotestosterone. The differences were not statistically significant.
17β‐Oestradiol Concentration in Spermatic Venous Blood with Increasing Age
Authors: Mannelli M. , Borrelli D. , Gonnelli P. , Fiorelli G. , Forti G. , Serio M. 
Published: May 2008

Androstenedione, testosterone and 17β‐oestradiol were measured in spermatic venous blood of 25 subjects (age range 20–70).Blood samples were taken during surgical intervention for hernia repair. While androstenedione and testosterone decreased significantly in spermatic venous blood with advancing age, 17β‐oestradiol was unchanged in the same subjects.These results seem to demonstrate that in senescence the increase of 17β‐oestradiol in systemic blood is not due to an increased secretion of this steroid by the human testis, but that it may be due to an increased peripheral conversion of the aromatizable androgens and to a reduction of the metabolic clearance rate of 17β‐oestradiol.
The Anti‐Reproductive Effects of Long Term Oral Administration of Cadmium on the Adult Male Rat
Authors: Zielinska‐Psuja Barbara , Lukaszyk A. , Senczuk W. 
Published: May 2008

The toxic effects of prolonged oral administration of cadmium on gametogenic and endocrine function of testes of adult rats were investigated. The experimental animals received daily, for 3, 6, 12 or 15 months, pellets containing 8.8 mg or 88 mg of cadmium chloride per kg body weight.The rats treated with the higher doses of cadmium for 12 and 15 months showed a marked reduction in absolute weight of testes accompanied by histological signs of impairment of seminiferous tubules. There were no necrotic changes but a number of cross‐sections of seminiferous tubules were deprived of spermatocytes and spermatids, reaching about 50 per cent of the tubules in the rats treated with higher doses of cadmium. The appearance of histological changes in rats treated for 12 and 15 months correlated with cumulation step of cadmium in testes and with alterations in serum concentration of LH but not of testosterone. Therefore, we suppose that under these experimental conditions the impairment of seminiferous tubules was induced by the direct influence of cadmium on germinal epithelium beginning the moment when cadmium reaches an effectively toxic concentration in testis.
Development of Diabetic‐Infertility induced by Streptozotocin in the Male Rat
Authors: Paz G. , Homonnai Z. T. 
Published: May 2008

Diabetes was induced in male rats by streptozotocin (60 mg/kg BW). Rats were sacrificed at 0, 1, 2, 3, 4, 5, 6, 8, 11 and 14 weeks after induction of diabetes. On autopsy the prostate, coagulating glands, seminal vesicles, epididymides and testes were isolated and weighed. Sperm isolated from the epididymis were characterized. The endocrine function of the testes was evaluated by counting number of Leydig cells per testes, testicular and serum testosterone and the testosterone production by the isolated Leydig cells.The following changes were found; testicular and serum testosterone decreased significantly starting the 2nd week of the diabetes, the atrophy of the accessory glands began shortly after diabetic induction and reached maximal values after 8 weeks, testicular weight began to decrease from the 8th week of the diabetic induction as well as the Leydig cells, the function of the epididymis was depressed as reflected in its weight and sperm quality.It can be concluded that the axis LH – Leydig cells is much more sensitive than FSH – tubuli to the block of LHRH secretion following streptozotocin induced diabetes.
Prostatitis and Male Infertility: A Pilot Study. Possible Increase in Sperm Motility with Antibacterial Chemotherapy
Authors: Baker H. W. G. , Straffon W. G. E. , Murphy G. , Davidson A. , Burger H. G. , de Kretser D. M. 
Published: May 2008

The cytology and bacteriology of urethral urine specimens and expressed prostatic secretions were examined in 24 infertile men suspected of having chronic prostatitis. Lencocytes were found and commensal bacteria cultured from most subjects but these were unrelated to clinical features, seminal characteristics or the outcome of treatment. Infection with pathogenic bacteria was not found in any subject. Despite this, there was a significant increase in sperm motility after antibacterial treatment, principally with erythromycin or cotrimoxazole, and three pregnancies coincided with the improvement.It is concluded that antibacterial therapy may improve fertility in patients with low sperm motility, but more investigation is necessary before the role of genital tract infection in male infertility can be placed in its proper perspective.
Motility Related to the Presence of Carnitine/Acetyl‐Carnitine in Human Spermatozoa
Authors: Johansen Liv , Bohmer Thomas 
Published: May 2008

Total carnitine, acetylcarnitine and carnitine acetyl transferase (E.C. 2.3.1.7) were measured in the plasma and spermatozoa fractions of 41 samples of human semen and the correlation with sperm motility and sperm density examined.It was confirmed that the concentration of total carnitine as well as of acetylcarnitine was 2–25 times higher and the activity of carnitine acetyl transferase 20–15 fold higher in spermatozoa than in seminal plasma. Sperm motility correlated with the concentration of acetylcarnitine (r = 0.6, P < 0.01) and of total carnitine (r = 0.55, P < 0.01) but not with the concentration of free carnitine nor with the activity of carnitine acetyl transferase in the spermatozoa. No correlation was found between sperm motility and the concentrations of acetylcarnitine, free carnitine or total carnitine in the seminal plasma.It is concluded that the amount of carnitine present in the spermatozoa probably provides a better index of epididymal function than the carnitine in the seminal plasma as the latter in influenced by af variable contribution from the other accessory sex organs.
Physico‐Chemical Characterization of the NADPH Dependent Soluble 3α‐Hydroxysteroid Oxidoreductase in the Rat Epididymis
Authors: Hastings Cetra D. , Hansson Vidar 
Published: May 2008

The present paper describes some important physico‐chemical characteristics of the NADPH dependent, 3α‐hydroxysteroid oxidoreductase (3α‐oxidoreductase) in the rat epididymis. This enzyme activity is stable in the presence of reducing agents (1–10 mM 2‐mercaptoethanol), EDTA (1 mM), and glycerol (10% v/v). The pH optium is in the physiological range (pH 6.0–8.0).Chromatography of epididymal cytosol fractions on calibrated G‐200 columns indicated a molecular weight of 34 000, and sucrose gradient centrifugation a sedimentation coefficient of 3.3 S20,w. The enzyme has a Stokes radius of approximately 25 Å. Calculation of molecular weight using both the sedimentation rate and the Stokes radius indicated a molecular weight of 34 400 and a frictional ratio (f/f0) of 1.17. The enzyme migrated with an Rx of 0.37 (relative to bromophenol blue) in 6.5% polyacrylamide gels and the iso‐electric point (pI) determined by iso‐electric focussing in 3.5 % polyacrylamide gels was 5.9. Further indication that the enzyme is negatively charged at neutral pH was obtained by DEAE‐cellulose ion exchange chromatography, from which the enzyme activity was eluted between 0.05 and 0.08M KCl.The epididymal 3α‐oxidoreductase is temperature sensitive, showing a greatly reduced activity after preincubation at 50°C for 30 min. Preincubation at 60°C caused a complete loss of enzyme activity. Interestingly, preincubation at 25°C for 30 min seemed to cause a significant increase in enzyme activity. Whether this is due to “temperature activation”, “cold inactivation” or to a temperature dependent disappearance of inhibitors is not known.
Leydig Cell Function in Rats Chronically Deprived of Normal Gonadotrophic Stimulation: The Effect of Treatment with hCG
Authors: Sharpe R. M. , Fraser H. M. 
Published: May 2008

Leydig cell function was assessed in adult rats 11 months after active immunization against LH‐RH. Immunized rats were divided into 2 groups according to whether the serum levels of LH and FSH were always undetectable (Group A) or were detectable at some time during the 11 months (Group B). Compared with controls, testicular weight was reduced by 84% (Group A) and 78% (Group B), but the number of Leydig cells per unit area of testis was increased by a factor of 7. Despite the latter change, the binding of 125I‐hCG per 20 mg testicular homogenate was 40% lower in immunized than in control rats. The serum level of testosterone in immunized rats was ≤ 0.1 ng/ml whilst levels ranged from 0.7 to 2.9 ng/ml in controls. In the same rats the testicular production of testosterone in vitro, both basally and after incubation with hCG or dibutryl cyclic AMP, was reduced by over 90% in immunized animals, although this impairment was more severe in Group A than in Group B animals.Leydig cell function was also assessed at 48 h after a single injection of 100 IU hCG. This treatment reduced the testicular binding of 125I‐hCG by over 89% in controls as well as both groups of immunized rats and caused a 3‐ to 4‐fold increase in the serum levels of testosterone in all animals. Following injection of hCG, the basal production of testosterone by the testis in vitro was doubled in controls whereas this increase was over 50‐fold in Group A immunized rats. In the latter, the maximum steroidogenic response of the testis in vitro was more than trebled by prior injection of hCG whilst this treatment caused a 30% reduction in the maximum response of testes from controls.
On the Postnatal Development of the Terminal Segment of the Seminiferous Tubules in Normal and Germ Cell Depleted Rat Testes
Authors: Osman D. I. , Plöen L. , Hagenäs L. 
Published: May 2008

The development of the terminal segment of the seminiferous tubules was studied in 5 to 50 days old normal rats. At the age of 5, 10, and 15 days the terminal segment contained fewer gonocytes or spermatogonia than did the corresponding seminiferous tubule. The differentiation of the terminal segment was obvious at 20 days of age due to the high number of germ cells in the seminiferous tubules, where the epithelium became stratified at this stage. The blood‐testis barrier in the terminal segment was chiefly established between 15 and 20 days of age as revealed by the lanthanum tracer technique.To study the effect of the germ cells on the differentiation, the germ cell depleted testes of prenatally irradiated rats were also studied. The modified Sertoli cells of the terminal segment were more vacoulated and had fewer lipid droplets and inter‐Sertoli cell junctions than did the Sertoli cells of the seminiferous tubules. The ultrastructure of the modified Sertoli cells of the terminal segment was similar in adult normal and adult SCO (Sertoli cell only) rats. The amount of lipid droplets in the Sertoli cells of SCO rats showed considerable variation among different tubular cross‐sections within one testis.
On the Microscopic Anatomy of the Rete Testis A Scanning Electron Microscopic and Light Microscopic Study
Authors: Nykänen Matti 
Published: May 2008

The microscopic anatomy of the transitional zone of the seminiferous tubules, the tubuli recti and the rete testis in adult rats was studied with histological serial sections, semithin sections and scanning electron microscopy. In paraffin section most transitional zones of the seminiferous tubules seemed to be obliterated by the modified Sertoli cells. Thinner plastic sections showed always a lumen, however. PAS ‐ positive material, throught to represent masses of degenerating spermatozoa surrounded by Sertoli cell nuclei was found in 20% of transitional zones. About 80% of the tubuli recti had an initial widening which surrounded the bulging Sertoli cell bodies of the transitional zones.The intratunical rete consisted of five to seven intercommunicating channels, usually of small caliber. One wide communication was regularly present, however. The extratesticular rete was usually formed of two wide cavities. From their subdivisions the five to seven ductuli efferentes arose. The rete epithelium varied from very thin squamous to cuboidal and even columnar. The epithelial cells contained a flagellum surrounded by peripheral microvilli. Loose connective tissue was found under the epithelium of all parts of the rete.
Mn2+‐dependent Adenylyl Cyclase (AC) in Rat Testis: Kinetic Properties and Optimalization of Assay Conditions
Authors: Gordeladze Jan Oxholm , Hansson Vidar 
Published: May 2008

The aim of the present study was to investigate some kinetic properties of the soluble Mn2+‐dependent adenylyl cyclase (AC) in rat testis and to examine the viability of this enzyme under various assay conditions.1. Constant AC activity was found during the first 35 min of incubation, and AC activity was proportional to protein concentrations in the range tested (10–45 μg/tube).2. The enzyme activity was constant for at least 24 h at 4°C and for at least 2 h at 35°C. At higher temperatures (above 45°C) the AC activity rapidly declines.3. The enzyme displays a pH optimum in the psysiological range (7.0–7.4) and increasing ionic strenght (0‐0.4 M NaCl/KCl) caused only a marginal decrease in enzyme activity.5. The soluble Mn2+‐dependent AC in rat testis could not be stimulated by hormones (hCG, FSH, prostaglandins), guanyl‐nucleotides (GMP‐P(NH)P, 2–4 times 10‐5 M) or F‐. Ca2+ (0.1–5 mM) caused a dose‐dependent stimulation of AC activity; the most pronounced effect was seen at low Mn2+ concentrations.6. The Km for MnATP2‐ was estimated to 3.0 mM and the Km for Mn2+ to 7.2 mM. Increasing concentrations of Mn2+ did not alter the affinity for MnATP2‐ and neither did varying levels of ATP affect the affinity for Mn2+.
Activation of Spermatozoal Forward Migration in vitro by Hydrocortisone
Authors: Cheng C. Y. , Boettcher B. , Tinneberg H. R. , Buxton J. 
Published: May 2008

The effects of hydrocortisone and cortisone on spermatozoal motility in vitro were tested. Hydrocortisone at concentrations of 50, 100 and 1000 nmoles/ml was effective in activating in vitro the forward migration and the motility of boar spermatozoa recovered from the cauda epididymidis. Where boar epididymal spermatozoa were incubated with hydrocortisone at concentrations of 50, 100 and 1000 nmoles/ml for between 0 and 24 h at 25°C in vitro, the spermatozoal motility was significantly higher than where no hydrocortisone was added. With ejaculated boar spermatozoa, hydrocortisone at concentrations of 100 and 1000 nmoles/ml increased the spermatozoal motility for between 0 and 2 h and at a concentration of 50 nmoles/ml increased spermatozoal motility for between 2 and 24 h at 25°C in vitro. After 4 h incubation, the effect of hydrocortisone at a concentration of 100 nmoles/ml on boar ejaculated sperm motility was not significantly different from the control. But, hydrocortisone at a concentration of 1000 nmoles/ml inhibited the forward migration of boar ejaculated sperm after it had been incubated with the sperm for 6 h. Cortisone, although structurally similar to hydrocortisone, had no significant effect in improving the motility of boar spermatozoa.Both hydrocortisone and cortisone had no demonstrable effect on the forward migration and the motility of human spermatozoa in vitro.,
LH/hCG Responsive Adenylyl cyclase in Rat Testis and Testes from Testicular Feminized Male (Tfm) Rats and Mice: Desensitization by Homologous Hormone
Authors: Hansson V. , Jahnsen T. , Purvis K. , Andersen D. , Birnbaumer L. 
Published: May 2008

Testes of testicular feminized (tfm) rats and mice, as well as of normal male rats contain an LH/hCG responsive adenylyl cyclase. Basal, as well as hCG stimulated activities were higher in tfm rats and mice than in normal rats. The presence of an LH/hCG responsive adenylyl cyclase in the testis of tfm rats and mice shows that the greatly elevated LH levels present in males having this syndrome, giving 80–90% reduction in LH//hCG receptors, do not cause an uncoupling of the remaining receptors from the adenylyl cyclase. It also shows that androgens are not essential for coupling of the LH/hCG receptors to the adenylyl cyclase.Injection of 200 IU of hCG into adult normal rats and tfm rats caused, after 48 h, a complete loss of LH/hCG stimulated adenylyl cyclase, whereas the FSH responsive adenylyl cyclase in both animal preparations was maintained. Desensitization of the LH responsive adenylyl cyclase by hCG in normal rats, confirms previous studies showing lack of hCG stimulated cyclic‐AMP secretion after a comparable dose of hCG in vivo. Similarly, hCG (50 IU) caused a transient loss of LH/hCG responsive adenylyl cyclase in tfm mice, with a complete disappearance of response after 24 h. At 48 and 72 h after injection of hCG the response gradually returned to normal. The fact that hCG caused a complete desensitization of the LH/hCG responsive adenylyl cyclase in both tfm rats and mice, proves that androgen receptor mediated events are not involved in hCG desensitization of the adenylyl cyclase in Leydig cells.
Filtering capacity of bovine cervical mucus towards abnormal forms of human‐ejaculated spermatozoa
Authors: Bergman A. , Amit A. , Yedwab G. , David M. P. , Homonnai Z. T. , Paz G. F. 
Published: May 2008

The filtration capacity of bovine cervical mucus (BCM), fresh bovine cervical mucus (FBCM) or frozen and thawed bovine mucus (BCMF) was studied, using human‐ejaculated spermatozoa in comparison with the properties of human cervical mucus (HCM).Thirty semen specimens of good quality were used in cervical mucus (CM) penetrations, using capillary tubes containing CM of 30 HCM, 77 FBCM and 77 BCMF samples. Spermiocytograms were carried out on semen and cervical mucus at 1st and 3rd centimeter of the capillary tube after one hour of incubation. Smears were stained by Papanicolau and the patterns of seven forms of sperm cells (normal, tapering, macrocephals, microcephals, pinhead, neck pathology and amorphous cells) were counted on a total of 100 cells in each slide.A clear, highly significant (P < 0.0001) selection of cells penetrating the CM has been shown, preventing certain abnormal forms from penetrating the CM (macrocephals, neck pathology and amorphous cells) and enabling good penetration of normal sperm forms and moderate penetration of tapering, microcephals and pinhead cells. On the average, a specimen with normal sperm forms of 72% showed a spermiocytogram of 90% normal forms at the 3rd centimeter of migration. The same patterns of filtration were recorded in all the three sources of CM. It is suggested that BCM be used as a filter towards abnormal sperm forms in a highly teratozoospermic ejaculate in order to improve its quality for artificial inseminations.
Prolactin secretion in the human male is increased by endogenous oestrogens and decreased by exogenous/endogenous androgens
Authors: Gooren L. J. G. , van der Veen E. A. , van Kessel H. , Harmsen‐Louman W. , Wiegel A. R. 
Published: May 2008

There is evidence that prolactin may be involved in testicular steroidogenesis, and we have therefore investigated whether there is feedback regulation of androgens/oestrogens on prolactin secretion in the human male. To assess this we have measured basal and TRH‐stimulated prolactin levels in:A) Six eugonadal men before and after 2 weeks' administration of the aromatase inhibitor Δ'‐testolactone, which led to a fall in oestradiol levels with unchanged levels of testosterone. In these patients, prolactin levels decreased.B) Six eugonadal subjects before and after 2 weeks' administration of dihydrotestosterone undecanoate. In these subjects, prolactin levels decreased.C) Six agonadal subjects, tested after 12 weeks' treatment with dihydrotestosterone undecanoate and compared toD) Six agonadal subjects who received no sex steroid treatment. Again, it was found that dihydrotestosterone treatment decreased prolactin levels in patients from Group C.E) Six eugonadal subjects were also studied before and after 6 weeks' administration of the androgen receptor antagonist, spironolactone, and this treatment increased Prl secretion.It is concluded that in the human male, endogenous oestrogens increase prolactin secretion whilst exogenous/endogenous androgens decrease prolactin secretion.
Levels of seminal free L(‐) carnitine in fertile and infertile men
Authors: Soufir J. C. , Ducot B. , Marson J. , Jouannet P. , Feneux D. , Soumah A. , Spira A. 
Published: May 2008

Data about the levels of free L‐carnitine, an epididymal marker in human semen, are contradictory and unclear, particuliarly in their releationship to fertility. This can perhaps be explained by the absence of any studies of seminal L‐carnitine in a large group of fertile men, and by the lack of consideration of factors influencing its secretion.In this study, free L‐carnitine was determined using a spectrophotometric method in deproteinized semen samples from fertile (n = 162) and infertile men without azoospermia (n = 303).Our results can be summarized as follows:

Infertile men were found to have significantly lower (P < 0.001) seminal carnitine levels (755 ± SD 499 nmoles) compared with fertile men (1010 ± 570).
Percentiles have been calculated for fertile men, and ‘normal’ values proposed (10th percentile = 390 and 90th percentile = 1830 nmoles).
Distribution of the levels of L‐carnitine were asymmetric in fertile as well as in infertile men (median: 922 nmoles vs 645).
In both groups, a significant increase in carnitine levels was observed with increasing length of abstinence, and a decrease in the ratio of carnitine/days of abstinence.

Methodological, physiological and pathological factors which may explain these results are discussed.