Spermatogenesis Levels Research Articles

Histopathological Patterns of Testicular Biopsy in Male Infertile Patients: A Cross-sectional Study

Introduction: The management of male infertility has undergone rapid changes with advancements in assisted reproductive techniques such as testicular sperm aspiration and microdissection, testicular sperm extraction (MicroTESE). However, testicular biopsy remains an important tool for diagnosing and managing male infertility, as well as assessing spermatogenesis levels. Aim: To examine the histological patterns of testicular biopsies in male patients with infertility. Materials and Methods: This cross-sectional study was conducted at the Department of Pathology, ESIC Super Specialty Hospital, Hyderabad, Telangana, India from May 2012 to May 2023. A total of 141 Tru-Cut biopsies from patients with male infertility were included based on predefined inclusion and exclusion criteria. Histopathologists labeled and reported the slides, noting the pattern of histopathology and level of spermatogenesis according to Johnson’s criteria. The data was analysed for percentages and mean values. Results: The majority of patients 43 (30.5%) exhibited normal histopathology, followed by Sertoli cell-only syndrome in 37 (26.24%) patients, and complete spermatogenic arrest in 14 (9.93%) patients. The least common pattern observed was incomplete spermatogenic arrest. Testicular atrophy was observed in 13 (9.22%) patients. Conclusion: This study highlights the importance of understanding the histological patterns observed in testicular biopsies, as it provides valuable insights to clinicians regarding the likelihood of obtaining spermatozoa for testicular sperm extraction in infertile males.

Human spermatogonia stem cells (SSCS) in a culture system with platelet rich plasma and correlations with spermatogenesis level

There are instances when the sperm fail to be obtained from the testes in assisted reproductive technology (ART) of azoospermia infertility due to spermatogenesis arrest. Therefore, spermatogonial stem cells (SSCs) may be used as an alternative management. Platelet rich plasma (PRP) is a concentrated source of growth factors that support the proliferation and differentiation of stem cells in vitro. The objective of this study was to determine the efficiency of PRP in supporting SSCs proliferation and differentiation and to assess the correlation between the level of spermatogenesis and the potency of proliferation and differentiation of SSC in vitro. SSCs were isolated from seven testicular tissue samples using sperm extraction (TESA/TESE) and were then further cultured into two groups, PRP and FBS. The resulting cells were quantitatively assayed by qRT-PCR towards the expression of PLZF, OCT4, and CKIT. The level of spermatogenesis was assessed from the histology measurement using Johnson scoring. Apoptosis was evaluated using the TUNEL and immunocytochemistry methods. This study showed that PLZF, OCT4, and CKIT were expressed in the resulting cell culture. The difference was statistically insignificant among PRP and FBS. There was a positive correlation between the potency of proliferation and differentiation of SSCs toward the level of spermatogenesis. PRP may support the maintenance of proliferation and differentiation of SSCs in vitro and could be developed as an alternative of FBS in the SSCs culture system. Keywords: Spermatogonial stem cells, Platelet rich plasma, Fetal bovine serum, Spermatogenesis, Cell culture.

New Insight into Molecular and Hormonal Connection in Andrology.

Hormones and cytokines are known to regulate cellular functions in the testes. These biomolecules induce a broad spectrum of effects on various level of spermatogenesis, and among them is the modulation of cell junction restructuring between Sertoli cells and germ cells in the seminiferous epithelium. Cytokines and androgens are closely related, and both correct testicular development and the maintenance of spermatogenesis depend on their function. Cytokines also play a crucial role in the immune testicular system, activating and directing leucocytes across the endothelial barrier to the inflammatory site, as well as in increasing their adhesion to the vascular wall. The purpose of this review is to revise the most recent findings on molecular mechanisms that play a key role in male sexual function, focusing on three specific molecular patterns, namely, cytokines, miRNAs, and endothelial progenitor cells. Numerous reports on the interactions between the immune and endocrine systems can be found in the literature. However, there is not yet a multi-approach review of the literature underlying the role between molecular patterns and testicular and sexual function.

Echinacoside Protects Against Dysfunction of Spermatogenesis Through the MAPK Signaling Pathway

Dysfunction at various levels of spermatogenesis (SD) is one of the important causes of infertility in men of reproductive age and requires advanced treatment strategies. Increasing evidence suggests that the therapeutic effects of echinacoside (ECH) mainly depend on their capacity to inhibit cell death. This study aimed to explore the therapeutic potential of ECH in SD rat models. Treatment with ECH reverted the morphological changes observed in testes with spermatogenesis dysfunction. It improved total sperm number, decreased the sperm deformity rate, and increased the sperm forward motility rate. The level of glutathione (GSH) was significantly higher in ECH-treated mice, whereas the lactate dehydrogenase (LDH) and SOD activities were improved compared with those in the spermatogenesis dysfunction model. Moreover, the increased expression of p38 and JNK was partially reversed by ECH. The number of normal TM3 cells increased gradually in an Echinacea dosage-dependent manner, suggesting that ECH promoted the proliferation of TM3 cells. In addition, treatment with ECH partially reversed the increased expression of p38 and JNK in TM3 cells. ECH protects against oxidative stress damage by activating antioxidant enzymes and MAPK signaling-related factors (p38 and JNK). It suggested that treatment with ECH alleviated spermatogenetic dysfunction of testes in male mice and it could be a promising strategy for patients suffering severe SD.

The patterns and occupational distribution of hormonal abnormalities among men investigated for infertility in some centers in the southwest, Nigeria

Male factor infertility results from dysfunction at various levels of spermatogenesis, sex hormone abnormalities, and occupation or workplace exposure to toxins are involved. This study was designed to determine the frequency of occupational distribution of men who were evaluated for infertility, the patterns of hormonal abnormalities, and to associate hormonal abnormalities with occupational categories in some centers in Osun State, Nigeria. Semen and 5 mL of whole blood were collected from the infertile men (n=319) who were referred to the laboratories for fertility investigation after physical and medical examination. Semen analysis was performed microscopically according to the World Health Organization manual while serum gonadotrophin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and prolactin were determined by Enzyme-linked Immunosorbent assay technique using reagents supplied by Biorex Diagnostics Limited, Antrim, United Kingdom. The subjects were grouped based on semen characteristics. More than half 164 (51.4%) of the subjects were within the age group of 31-40 years, followed by 70 (21.9%) in the age group of 21-30 years, while 67 (21.0%) was in the age group of 41-50 years. Some 133/319 (41.7%) of the subjects had normal sex hormone levels while 186/319 (58.3%) had abnormal hormone levels. The patterns of hormonal abnormalities observed were 96/186 (51.6%) normogonadotrophin-hypogonadism, 49/186 (26.3%) normogonadotrophin-hypergonadism, 14/186 (7.5%) elevated FSH levels, 15/186 (8.1%) elevated LH levels, 07/186 (3.8%) hypergonadotropic-hypergonadism, and 05/186 (2.7%) hyperprolactinemia. Artisans (OR 1.2252 95%CI 0.367-2.472), workers in chemical related industries (OR 1.667, 95%CI 0.594-4.676), and businessmen (OR 1.200, 95%CI 0.110-3.49) are more likely to be predisposed to hormonal abnormalities. The patterns of hormone abnormalities as well as their relative proportions are slightly different from those reported previously. Some occupations may predispose workers to hormonal disorder than the others. This is a cross-sectional study of males investigated for infertility; the contribution and patterns of hormonal abnormalities were evaluated. The possible association between workplace and infertility that may assist in the management of patients with male infertility was evaluated.

HASPIN kinase inhibitor CHR-6494 suppresses intestinal polyp development, cachexia, and hypogonadism in Apcmin/+ mice.

HASPIN has been identified as a nuclear Ser/Thr kinase specifically expressed in haploid germ cells. HASPIN kinase inhibitors were recently isolated, and their antitumor activity reported. Colorectal cancer occurs with high incidence worldwide. In this study, we examined whether HASPIN inhibitor CHR-6494 suppresses cancer progression in ApcMin/+ mice, a familial colon tumor disease model. Mice were treated by intraperitoneal injection of CHR-6494 for 50 days. Following the treatment period, intestinal polyps were counted and testosterone and spermatogenesis levels were observed. Intraperitoneal administration of CHR-6494 significantly inhibited intestinal polyp development and recovered body weight in ApcMin/+ mice. Although spermatogenesis was inhibited with increasing age in ApcMin/+ mice, CHR-6494 significantly improved blood testosterone levels and spermatogenesis. Our results suggest that HASPIN inhibitors may be useful as anti-cancer agents and for the treatment of hypogonadism in colorectal cancer patients.

Investigating the Effect of Fennel and Cinnamon Combined Extract on Spermatogenesis and Testis Tissues in Busulfan Induced Infertile Rats

Introduction: Busulfan is one of the common cancer treatment drugs with infertility side effects. Fennel and cinnamon are two medicinal plants with fertility enhancement properties. The aim of this study was to investigate the effects of fennel and cinnamon on busulfan induced infertile rats. Materials and Methods: Forty male Wistar rats were divided into four groups including: sham group: healthy rats without intervention, control group: Busulfan treated rats, fennel group: busulfan and fennel extract treated, fennel and cinnamon group: busulfan, fennel and cinnamon extract treatment. Testicular tissues were sampled and the testicular physical parameters and spermatogenesis level were evaluated by H & E staining and optical microscopy imaging. Results: The biggest and the smallest testis lengths were observed in cinnamon + fennel and fennel groups respectively (P < 0.05). The highest and lowest sperm levels were observed in the cinnamon + fennel group and fennel group respectively (P < 0.001). The total average of reproductive cells was the most in the cinnamon + fennel group (104.17) and had the least level in the control group (26.29). Conclusions: The combined extract of fennel and cinnamon significantly protect the testicular tissues against infertility effect of busulfan. However, the fennel extract alone increased the effect of busulfan in rats.

Klinefelter syndrome and fertility-Impact of X-chromosomal inheritance on spermatogenesis.

With the use of testicular sperm extraction (TESE), spermatozoa can be retrieved in about 30%-50% of men with Klinefelter syndrome (KS). The reason for the absence or presence of spermatozoa in half of the men with KS remains unknown. Therefore, the search for an objective marker for a positive prediction in finding spermatozoa is of significant clinical value to avoid unnecessary testicular biopsies in males with (mostly) low testicular volume and impaired testosterone. The objective of this study was to determine whether paternal or maternal inheritance of the additional X-chromosome can predict the absence or presence of spermatogenesis in men with KS. Men with KS who have had a testicular biopsy for diagnostic fertility workup TESE were eligible for inclusion. Buccal swabs from nine KS patients and parents (trios) were taken to compare X-chromosomal inheritance to determine the parental origin of both X-chromosomes in the males with KS. Spermatozoa were found in TESE biopsies 8 of 35 (23%) patients after performing a unilateral or bilateral TESE. Different levels of spermatogenesis (from the only presence of spermatogonia, up to maturation arrest or hypospermatogenesis) appeared to be present in 19 of 35 (54%) men, meaning that the presence of spermatogenesis not always yields mature spermatozoa. From the nine KS-trios that were genetically analysed for X-chromosomal inheritance origin, no evidence of a correlation between the maternal or paternal origin of the additional X-chromosome and the presence of spermatogenesis was found. In conclusion, the maternal or paternal origin of the additional X-chromosome in men with KS does not predict the presence or absence of spermatogenesis.

Diagnosis of acquired obstructive azoospermia and surgical treatment outcome analysis

Objective To study the diagnosis of acquired obstructive azoospermia and analyse the outcomes of surgical treatment. Methods One hundred and six patients were diagnosed with acquired obstructive azoospermia at our center between January 2009 and May 2014.A total of 106 patients aged from 22 to 46 years (mean age: 30 years old), their duration of infertility were 2 to 16 years, mean 3 years. All patients had clinic findings related to azoospermia, including no sperm found in semen analyses and centrifuged semen sample, normal scrotal ultrasonogram and serum sex hormone, 71 cases with a history of natural conception or normal semen analyses, 35 cases with a normal level of spermatogenesis confirmed by testicular biopsy. Physical examination and ultrasonography of the genital system shown that the seminal duct were normally developed in all patients. One hundred and six patients with acquired obstruction were treated by multiple surgical techniques and follwed–up. Of them, 15 surgical explorations and 91 reconstructions, including 11 transurethral incision of ejaculatory duct with holmium laser, 6 microscopic vasovasostomy at inguinal region, 10 microscopic vasovasostomy, 47 modified transverse intussusception vasoepididymostomy and 17 combined surgical techniques. Patency was defined as >10 000 sperm/ ml of semen. Results The postoperative follow–up time was 12 months to 52 months. Eighty two had return of sperm to ejaculate and nine failed, the overall patency rate was 90.1% (82/91). The patency rate was 90.9%(10/11)、83.3%(5/6)、100.0%(10/10)、89.4%(42/47)、88.2%(15/17)for transurethral incision of ejaculatory duct with holmium laser, microscopic vasovasostomy at inguinal region, microscopic vasovasostomy, modified transverse intussusception vasoepididymostomy and combined surgical techniques, respectively. Thirty two patients naturally achieved conception. Postoperative complications included one case of fever, one hemospermia and one delayed wound healing at scrotum, all were cured by medication. No severe complication were observed. Conclusion Azoospermia with normal testicular spermatogenesis and normally developed seminal duct was classified as acquired obstructive azoospermia. Surgical treatment for acquired obstruction have a favorable patency and pregnancy rate. Key words: Azoospermia; Diagnosis; Surgical treatment

In-depth characterization of human testicular tissue from patients suffering from gender identity disorder (GID) undergoing sex-reassignment surgery (SRS)

According to guidelines Male-to-Female transsexuals receive anti-androgens and estrogens for up to 2 years to feminize the body and to regress testes prior to Sex Reassignment Surgery (SRS). This study aims to characterize endocrine parameters and testicular damage from Gender Identity Disorder (GID) patients undergoing SRS. 36 patients underwent SRS at two German centers between January 2012 and April 2013. Data and testes were collected prospectively. Tissue from men with obstructive azoospermia served as control. The study was ethically approved by the Westfalian Medical Board (code: 2012-555-f-S). Tissue was fixed in Bouin and embedded in paraffin. PAS-staining was performed, the level of spermatogenesis (LoS) and morphological features were determined using morphometric procedures. Six IHC-markers for somatic and germ cell function were stained. Serum hormonal profiles were measured by Autodelfia. Intratesticular testosterone levels were determined from frozen tissue extracts by radioimmunoassay. Questionnaires about hormonal treatment were collected. 46 testes were analyzed. Histologically 26% showed complete spermatogenesis, 28% meiotic arrest, 33% spermatogonial arrest, 11% Sertoli-cell only syndrome and 2% complete hyalinization. Testis volume (2-25 ml) correlated with the LoS associated with an increase of interstitium & seminiferous epithelium and loss of tubular lumen. While 3-ß-HSD staining revealed no obvious changes, the number of LH-receptor positive cells declined in regressed testes. In contrast to ITT-levels, which were unrelated to histological findings, serum testosterone- and LH-levels decreased in accordance to the LoS. Considering all patients received the same medication our data indicate a diverse response in respect to spermatogenic and steroidogenic regression. The reason could be deviation from therapeutic regimen or individually different response. We suggest GID patients should be more intensely monitored prior to SRS.

Varicocele repair for nonobstructive azoospermia

To evaluate the role of varicocelectomy in the management of patients with varicoceles and nonobstructive azoospermia and to review predictors of successful outcomes. Several small, retrospective, noncontrolled studies have documented return of sperm to the ejaculate in up to 56% of men with nonobstructive azoospermia (NOA) following varicocele repair. Additionally, a recent meta-analysis has reported a 6% spontaneous pregnancy rate in amongst NOA patients who underwent varicocele repair, regardless of surgical technique. Although these observations are promising, evidence for whether or not varicocele repair significantly improves spermatogenesis within an impaired testicle is conflicting. No clear predictors of success following varicocele repair have been identified, but a certain level of spermatogenesis on testicular biopsy appears to be necessary for a desirable outcome after varicocele repair. The role of varicocelectomy for the treatment on NOA is controversial. Prospective, controlled studies are needed in order to define the true benefit of varicocele repair in men with NOA, in terms of improvement in semen parameters, testicular sperm retrieval rates, and pregnancy outcomes.

Alterations of the USP26 gene in Caucasian men

The Ubiquitin Specific Protease 26 gene is a testis-specific gene that is located on the X chromosome. Sequence variants of this gene were previously reported in men with azoospermia caused by defects at the level of spermatogenesis. Especially a cluster of three changes (c.370_371insACA, c.494T>C and c.1423C>T) was frequently observed. To further define the role of this cluster of sequence variants in the USP26 gene, we have now analysed 202 control samples and 146 patients of Caucasian origin with cryptozoospermia or oligozoospermia. The detection method was based on a restriction reaction, by which the change c.494T>C can be detected. In none of the patients, the change c.494T>C was observed. Only in one man with normal spermatogenesis this sequence variant was detected. Sequencing can confirm the presence of the three changes of the USP26 gene. These data indicate that the cluster of changes is not restricted to men with severe testicular dysfunction.

Effects of Aging and Niche Microenvironment on Spermatogonial Stem Cell Self-Renewal

Aging is evident in most tissues and organ systems, but the mechanisms of aging are difficult to identify and poorly understood. Here, we test the hypothesis that aging results in uncorrected defects in stem cell and/or niche function, which lead to system failure. We used the spermatogonial stem cell (SSC) transplantation assay to determine the effect of aging on testis stem cell/niche function in mice. Between 12 and 24 months of age, male mice experienced a declining level of fertility associated with decreased testis weight, level of spermatogenesis, and total stem cell content. However, when stem cells were consecutively passaged at 3-month intervals to testes of young males, these stem cells continued to produce spermatogenesis for more than 3 years. Thus, SSC self-renewal continues long past the normal life span of the animal when the stem cell is continually maintained in a young niche/microenvironment. Moreover, these data suggest that infertility in old males results from deterioration of the SSC niche and failure to support an appropriate balance between stem cell self-renewal and differentiation.

Intracytoplasmic injection of spermatids retrieved from testicular tissue: influence of testicular pathology, type of selected spermatids and oocyte activation.

Spermatid microinjection into oocytes has proven to be a successful assisted reproduction procedure in the animal model and in the human species, since in the latter a few full-term pregnancies were actually obtained. Patients entering our spermatid injection study included those with a total absence of spermatozoa in the testicular tissue notwithstanding previous positive biopsies (n = 29): an obstructive problem (n = 3), secretory azoospermia (n = 26), and those with total arrest at the spermatogenesis level in previous explorative biopsies (n = 15). In the latter group, absence of spermatids was recorded in four cases. Mature, elongated, elongating and round spermatids (ROS) were injected in respectively 3, 2, 3, and 32 attempts. A total of 260 metaphase II oocytes were injected with ROS, 36 oocytes with spermatids at other stages of maturity. The rates of oocytes showing two pronuclei (2PN) and two polar bodies reached 22% and 64% respectively after injection of round or elongated-mature spermatids. The fertilization rate after ROS injection was influenced by the percentage of spermatozoa observed in a previous biopsy. Patients with a positive preliminary biopsy had significantly more 2PN (33%) when compared to those with a severe spermatogenic dysfunction and in whom no spermatozoa were found (only 11%) (P < 0.05). Incubation of oocytes in calcium ionophore after ROS injection had a positive effect on the rate of 2PN formation (36 versus 16%). Ninety per cent of all the normally fertilized oocytes cleaved. The percentage of grade A and B embryos depended on the type of injected cells: 12% after ROS and 30% with the other types of haploid cells. A total of 39 transfers resulted in five pregnancies: three full term with healthy babies delivered (one after ROS injection, and two after injection of an elongating and a mature spermatid), one 4 months ongoing (after elongating spermatid injection) and one miscarriage at 4 weeks (after elongated cell injection). Compared to our conventional intracytoplasmic sperm injection-testicular sperm extraction (ICSI-TESE) programme, the implantation rate after ROS injection was very low (5.5 versus 10.5%).

Comparison between testosterone enanthate-induced azoospermia and oligozoospermia in a male contraceptive study. II. Pharmacokinetics and pharmacodynamics of once weekly administration of testosterone enanthate.

Hormonal suppression of spermatogenesis is currently being investigated as a method of reversible male contraception. However, administration of exogenous testosterone (T) induces azoospermia in only 40-70% of Caucasian men, whereas the remainder suppresses to severe oligozoospermia (< 5 x 10(5)/mL). The reason(s) for the heterogeneity in the spermatogenic response is not clear. We have prospectively investigated the possibilities that higher plasma concentrations of T and/or differences in the extent and rate of gonadotropin suppression could maintain a low level of spermatogenesis in subjects taking part in a clinical efficacy trial of hormonal male contraception. Thirty-three healthy adult men, aged 21-41 yr, were given 200 mg T enanthate (TE), im, weekly for up to 18 months. Azoospermia was achieved in 18 men (55%) after 20 weeks of treatment, at which time the remaining 15 (45%) stabilized at a mean sperm density of 2.0 +/- 0.8 (+/- SD) x 10(6)/mL. These 15 subjects remained oligozoospermic for the rest of the efficacy study. To compare the pharmacokinetics and pharmacodynamics of TE between the azoospermic and oligozoospermic responders, plasma samples were obtained immediately before and 1, 2, 4, and 7 days after the 1st and 16th TE injections. Further samples were taken after 2, 4, 8, and 12 weeks of treatment. Plasma concentrations of total, free, and non-sex hormone-binding globulin (non-SHBG)-bound T, estradiol, LH, and FSH were measured. Compared to baseline, preinjection levels of total T increased 2.5-fold, reaching a steady state around 12 weeks of treatment. Peak concentrations of total T increased by 5-fold, but free and non-SHBG-bound T levels were increased by 10-fold after 16 weeks. The plasma levels of estradiol showed similar changes as T. However, neither T (bound or free) nor estradiol was significantly different between azoospermic and oligozoospermic responders. Plasma SHBG was reduced to a similar degree in both groups of men after 16 weeks of TE treatment. Plasma concentrations of both LH and FSH decreased rapidly after the first TE injection; a significant decline in LH was detectable after 24 h. Mean levels of both gonadotropins decreased to less than 0.5 U/L by the end of 4 weeks and to below the limit of sensitivity of the assays (0.05 IU/L) by 12 weeks. There were no significant differences in plasma concentrations of LH or FSH or in the rates of suppression between azoospermic and oligozoospermic responders. We conclude that the polymorphism of spermatogenic suppression in response to exogenous T is unlikely to be due to differences in the pharmacokinetics or pharmacodynamics of TE or in the sensitivity of the hypothalamo-pituitary-testicular axis to sex steroid inhibition. Measurements of total plasma T considerably underestimate the increase in bioavailable T during the weekly TE regimen.

Leydig cell cytoplasmic content is related to daily sperm production in men.

The relationship between the abundance of specific Leydig cell organelles and daily sperm production (DSP) was determined. Testes from 10 men (26-53 years of age) were obtained at autopsy within 10 h of traumatic death or heart failure and fixed by vascular perfusion. Testicular tissue was processed for light and electron microscopy. DSP/testis and Leydig cell cytoplasmic volume/testis were determined by stereology of histologic sections. The Leydig cell organelle content was determined by point counting electron micrographs for smooth endoplasmic reticulum (SER), rough endoplasmic reticulum, mitochondria, lipofuscin pigment, lipid, Golgi bodies, and Reinke crystals. Men were divided equally into two groups based on DSP/testis. Men with low DSP/testis had less SER volume density (P less than 0.01) and lower SER volume per testis (P less than 0.05) than men with high DSP. Other organelles were unrelated to DSP. When all men were combined, the volume density of SER (r = 0.80; P less than 0.01), the volume SER per testis (r = 0.69; P less than 0.05), and the volume SER per Leydig cell (r = 0.84; P less than 0.01) were significantly related to DSP. Hence, there appears to be a significant relationship between Leydig cell SER and the level of spermatogenesis in men.

Androgens in male rat reproductive tract fluids: hypophysectomy and steroid replacement.

The control of androgen concentrations in the intraluminal fluids of the male reproductive tract is not well understood. The present experiments were performed to determine the effects of hypophysectomy, hypophysectomy plus testosterone (T), and hypophysectomy plus pregnenolone treatment on intraluminal androgen concentrations in the adult rat testis and epididymis. T and 5 alpha-dihydrotestosterone (DHT) concentrations were determined in the vascular, interstitial, and intraluminal compartments of the epididymis. Testicular and epididymal morphology also were examined under light microscopy. Hypophysectomy of at least 5 days duration significantly reduced T and DHT concentrations in serum, tissues, and intraluminal fluids of the reproductive tract. T replacement for 14 days, which produced peripheral T concentrations of 5 ng/ml, did not support intraluminal androgen concentrations in the seminiferous tubules equivalent to controls; rete testis androgen concentrations were similar to controls, however. Pregnenolone administration at 2 mg X rat-1 X day-1 for 14 days did not maintain spermatogenesis nor intraluminal T concentrations in the seminiferous tubules equivalent to controls; however, a low level of spermatogenesis continued when intraluminal and tissue androgen concentrations were maintained at 10-20% of controls by either the testosterone and pregnenolone treatments.

Comparative effects of chemosterilants on spermatogenic stages in the house fly. II. Recovery of fertility and sperm transfer in successive matings after sterilization with 1,3-propanediol dimethanesulfonate or x-rays.

When 2- to 3-day-old male Musca domestica L. (Diptera: Muscidae) were injected with 20 µg of 1,3 propanediol dimethanesulfonate, most sperm had dominant lethal mutations so the males were sterile in the initial matings. Testes sectioned at regular intervals postinjection contained damaged meiotic and premeiotic cells; pycnotic nuclei were observed 1 day postinjection; and spermatocytes with chromosomal bridges and fragments were observed the 2nd and 3rd day postinjection. Also, the testes contained few spermatocytes the 4th and 5th day postinjection, thus spermatids were scarce the 5th and 7th day. However, sperm production was never completely interrupted, and the level of spermatogenesis 11-13 days postinjection was returning to normal levels. Incontrast, when males were treated with 3 kR of x-rays, all sperm contained dominant lethal mutations, all gonialcells were killed, and the spermatogenic cycle ceased. Males that mated repeatedly after treatment with the chemosterilant recovered their fertility and became as fertile as the controls after 7-8 matings, but the males that did not remate repeatedly did not recover fertility. There was little difference between fertility of males mated 1, 7, or 12 days posttreatment if they remained celibate in the interim. Irradiated males were able to transfer sperm for many matings over several weeks.

Autoradiographic Study of Spermatogenesis inAsellus AquaticusDuring Reproductive Stasis

SUMMARYBy means of autoradiographic methods, after the injection of 3H-thymidine, a study has been made of the spermatogenesis of Asellus aquaticus (Crust. Isop.) in the period of winter reproductive stasis and during the period of normal reproduction, in order to determine whether the reproductive stasis somehow takes place at the level of spermatogenesis by creating a block in the maturation of the male germinal cells or by slowing down the spermatogenetic cycle. The comparative study of indiduals in stasis and individuals not in stasis has revealed a substantial identity of results. The time that elapses between the injection of the radioactive precursor and the appearance of labeled sperms is 19 days in both types. A small number of nurse cells incorporate the 3H-thymidine very quickly and continue to be labeled to the same degree even after 30 days.