Ketone bodies could support the motility but not the acrosome reaction of mouse sperm

Ketone bodies, D-beta-hydroxybutyrate and acetoacetate, produced by the metabolism of fatty acids, are an important energy source for many organs, especially the heart, kidney and brain. They are utilized by the body with the help of succinyl CoA transferase (SCOT), which is ubiquitously expressed in various organs. Previously, we identified a novel SCOT-t specifically expressed in testicular germ cells and sperm, substituting somatic cell-type SCOT, however the physiological role of SCOT-t had not then been clarified. In the present study, we investigated the effects of ketone bodies, the substrate of SCOT-t, on the motility and acrosome reaction of mouse sperm. D-beta-hydroxybutyrate and acetoacetate both stimulated the motility of sperm as glucose or pyruvate. The glycolysis inhibitor stopped the motility of sperm mediated by glucose but not by D-beta-hydroxybutyrate. In contrast, ketone bodies did not stimulate the activation of the acrosome reaction of sperm, different from the effect of glucose. These results indicate that ketone bodies could be involved in sperm movement but not the acrosome reaction and the SCOT-t enzyme we have identified in sperm mitochondria may have important roles in the activity of sperm, resulting in male infertility when its function is disabled.     

Non-tumoural parenchyma in Leydig cell tumours: pathogenetic considerations

Little is known about the pathogenesis of Leydig cell tumours (LCTs) of the testis. The observation of several associated dysgenetic features in the non-tumoural parenchyma and in the contralateral testes of men with testicular germ cell neoplasms has served as the basis to propose that there may be a common mechanism for different male reproductive disorders. However, the possible relationship between LCTs and other testicular lesions has not been explored. Here we describe the presence of primary lesions in the non-tumoural parenchyma of testes with LCT, from which we try to establish possible pathogenetic associations. We studied the non-tumoural parenchyma adjacent to 16 LCT specimens. Parameters as Leydig cell hyperplasia (LCHY), qualitative evaluation of the germinal epithelium and spermatogenesis, the presence of Sertoli cell-only tubules (SCOT), and the Sertoli cell nuclear morphology were consistently assessed in all cases. SCOT associated with Sertoli cell dysgenetic morphology was the most frequent finding, present in 50% of the cases. Another interesting finding was the presence of LCHY in four cases (25%). Abnormal spermatogenesis was found in 81.25% of the cases, and it consisted of lesions of the adluminal or basal compartments of seminiferous tubules. The occurrence of either dysgenetic Sertoli cells or LCHY adjacent to LCTs could represent primary anomalies, resulting from a common insult also involved in tumourigenesis. The abnormalities in spermatogenesis observed here are likely to represent consequences of either tumour compression or abnormal hormonal production. The significance of these associations merits further investigation regarding a common pathogenesis.     

Thyroid hormones: their role in testicular steroidogenesis

Thyroid hormones are important for growth and development of many tissues. Altered thyroid hormone status causes testicular abnormalities. For instance, juvenile hypothyroidism/neonatal transient hypothyroidism induces macroorchidism, increases testicular cell number (Sertoli, Leydig, and germ cells) and daily sperm production. Triiodothyronine (T3) receptors have been identified in sperm, developing germ cells, Sertoli, Leydig, and peritubular cells. T3 stimulates Sertoli cell lactate secretion as well as mRNA expression of inhibin-alpha, androgen receptor, IGF-I, and IGFBP-4. It also inhibits Sertoli cell mRNA expression of Müllerian inhibiting substance (MIS), aromatase, estradiol receptor, and androgen binding protein (ABP) and ABP secretion. T3 directly increases Leydig cell LH receptor numbers and mRNA levels of steroidogenic enzymes and steroidogenic acute regulatory protein. It stimulates basal and LH-induced secretion of progesterone, testosterone, and estradiol by Leydig cells. Steroidogenic factor-1 acts as a mediator for T3-induced Leydig cell steroidogenesis. Although the role of T3 on sperm, germ, and peritubular cells has not yet been completely studied, it is clear that T3 directly regulates Sertoli and Leydig cell functions. Further studies are required to elucidate the direct effect of T3 on sperm, germ, and peritubular cells.     

Evolution of somatic and germ cell populations after busulfan treatment in utero or neonatal cryptorchidism in the rat

Summary.  In order to elucidate the respective effects of depletion of germ cells and of increase in testicular temperature, rats of the same Wistar strain were rendered experimentally bicryptorchid or sterilized by a busulfan injection in utero and compared to control animals. In both models, germ cells were depleted but numeric evolution and functions of somatic cells differed. The aim of that work was to compare the numeric evolutions of testicular somatic and germ cells to their respective functions in each model before puberty and in adult rats of the same strain. Serum concentrations of FSH, LH and testosterone were compared at 20, 40 and 110 days of age. Histological analyses of Sertoli and germ cells in the seminiferous tubules and of Leydig cells in the intertubular tissue were performed before puberty and at adulthood. Testosterone serum concentrations were depleted in both models starting at 40 days of age and more in busulfan-treated rats. Both FSH and LH levels were increased from 20 days onwards in experimental rats. Additional cryptorchidism in busulfan-treated rats depressed the serum testosterone concentration. At 17 days of age, the cryptorchidism do not modify somatic or germ cell populations while busulfan treatment has induced a decrease of both these populations. Conversely, the cross sectional area of the somatic testicular cells was not affected whatever the treatment. In adult testes of busulfan-treated and cryptorchid rats, the total numbers of Sertoli and Leydig cells and of germ cells per testis were decreased. The cellular size of the perivascular Leydig cells was not modified by any of the treatments whereas the size of the Sertoli cells was reduced.
In conclusion, in both models the absence of germ cells induces a decrease in Sertoli cell function, while the increase in testicular temperature provokes degeneracies of Sertoli and germ cells in the seminiferous tubules of the rat.     

Identification of differentiation antigens in mouse testicular germ cells recognized by monoclonal antibody TRA 55

We have isolated a monoclonal antibody (mAb) TRA 55, which recognizes mouse testicular germ cells from mid-pachytene spermatocytes to the early stages of haploid spermatids during differentiation. Immunohistochemical analysis produced strong positive staining of the nuclei and faint staining in the cytoplasm of germ cells. At meiotic division, when the nuclear membrane disappeared, a specific positive signal could be observed on metaphase chromosomes. When germ cells produced haploid spermatids, antigenicity became suddenly weak and soon disappeared. TRA 55 did not react with testicular somatic cells, such as Sertoli cells or Leydig cells. Western blot analysis of the whole testis showed four positive bands with molecular weights of 43, 46, 49 and 55 kDa. Three bands of 43, 49 and 55 kDa, and a single band of 46 kDa were recovered in cytoplasmic and nuclear fractions of testicular germ cells, respectively. Chronological changes in the Western blot pattern indicated that these antigens became detectable in the testis at the age of 10 days. Furthermore, all antigens were resistant to periodate treatment, suggesting that the epitope was in an amino acid rather than a sugar moiety. These antigen molecules may play important roles in the differentiation of germ cells at the later stages of meiotic prophase and meiotic division in the mouse testis.     

A germ cell-specific nuclear antigen recognized by a monoclonal antibody raised against mouse testicular germ cells

A monoclonal antibody (mAb TRA104) raised against mouse testicular germ cells was able to recognize the nuclei of testicular germ cells at all the stages of differentiation from embryonic gonocytes to spermatids and did not react with any somatic cells. The antigen recognized by mAb TRA 104 was exclusively present in testicular extracts. The molecular weights and isoelectric point (pI) of the antigens determined by Western blotting analysis were 60–110 kDa and 7.2, respectively. This antigen(s) is referred to as a germ cell-specific nuclear antigen(s) (GENA) since GENA was first detected specifically in the genital ridge at around 12 days of gestation by Western blotting analysis. In the testis, the expression increased gradually until adulthood whereas it was lost in the ovary by postpartum day 5. Thus, GENA is a molecule(s) exclusively present in the nuclei of germ cells and may be a useful marker with which to study the mechanism of germ cell development and differentiation at the molecular level.     

Presence of IL-18 in testicular tissue of fertile and infertile men

Recently, IL-18 was identified in human testes. Moreover, an inverse correlation was found between the levels of IL-18 and the number and motility of spermatozoa. We examined the presence of IL-18 protein in normal and impaired spermatogenesis. Testicular tissue specimens were taken from 25 nonobstructive azoospermic patients undergoing testicular sperm extraction and from autopsies of three healthy controls. The presence of IL-18 in human testicular cells was examined by immunohistochemical staining of paraffin-embedded sections, using a specific antibody for human IL-18. In testicular tissue of healthy controls as well as in study cases, presence of IL-18 was identified in somatic, mitotic, meiotic and post-meiotic cells in correlation with their presence. In all patients, Leydig cells were less intensively stained. Mitotic cells were immunostained in the control group and less intensively in hypospermatogenesis and maturation arrest subgroups. Primary spermatocytes were in general most efficiently stained. The expression of IL-18 mRNA (as examined by real-time PCR analysis) showed significantly lower expression in testicular tissues with impaired spermatogenesis when compared to normal tissues. We report the first study demonstrating the presence of IL-18 in human testicular tissue at the protein level. The presence of this cytokine in somatic as well as in different types of germ cells may suggest its involvement in the regulation of the spermatogenic process and steroidogenesis under physiological and pathological conditions.     

Expression of Apg-1, a member of the Hsp110 family, in the human testis and sperm

BACKGROUND: Apg-1 encodes a heat shock protein belonging to the Hsp110 family and is inducible by a 32 degrees C to 39 degrees C heat shock in somatic cells. In mouse testicular germ cells Apg-1 mRNA is constitutively expressed depending on the developmental stage. As human Apg-1 has recently been identified, the expression of Apg-1 in the human testis and sperm was investigated. METHODS: Expression and heat-inducibility of Apg-1 in the human testicular germ cell tumor cell line, NEC8, was analyzed. Using an antimouse Apg-1 antibody, expression of Apg-1 in the human testis and sperm was examined by western blotting after confirmation of the specificity of the antibody. The cells expressing Apg-1 in the testis were further determined by immunohistochemistry. RESULTS: Slight induction of Apg-1 mRNA was detected in NEC8 cells after 32 degrees C to 39 degrees C temperature shift. In the human testis, the antibody specifically recognized Apg-1, which was absent in the testis without germ cells (Sertoli-cell-only syndrome) or arrested at spermatogonia. Spermatocytes and spermatids, but not testicular somatic cells, were positively stained with the anti-Apg-1 antibody. By western blot analysis, Apg-1 was detected in the preparation enriched for sperm from normal volunteers and infertile patients, but not from azoospermia patients. CONCLUSION: Apg-1 is developmentally expressed in human testicular germ cells and sperm, suggesting its role in spermatogenesis and fertilization. Identification of substrates for Apg-1 chaperone activity will help elucidate its function.     

Conservative management of small testicular tumors relative to carcinoma in situ prevalence

PURPOSE: We evaluated the prevalence of carcinoma in situ (CIS) in orchiectomy specimens performed for germ cell tumors smaller than 40 mm in diameter to propose an appropriate conservative approach to bilateral tumors or tumor of a solitary testis. MATERIALS AND METHODS: Of 127 patients treated with orchiectomy between 1990 and 2002, 41 who presented with a tumor of less than 40 mm in diameter were selected for histological analysis of testicular parenchyma. The morphological items assessed were CIS, spermatogenesis and Leydig cell hyperplasia. RESULTS: CIS was observed in 39 of the 41 patients (95%). CIS was evenly distributed throughout the testicular parenchyma (ie around and beyond the tumor) in all 39 cases. Spermatogenesis was observed in 12 of 41 specimens (29%), spermatogenesis without spermatozoa was noted in 14 (34%) and absent germ cells were found in 15 (37%). Leydig cell hyperplasia was observed in 24 cases (58%). CONCLUSIONS: Histological analysis of whole orchiectomy specimens showed that CIS is almost always present in testicular parenchyma adjacent to germ cell tumor. In bilateral testis cancer or cancer occurring in a solitary testis tumorectomy plus radiotherapy appears to be the appropriate treatment in patients with a small tumor and no other risk factors. In patients who wish to father a child and have preserved spermatogenesis the natural history of CIS allows the postponement of testicular radiotherapy after orchiectomy, giving the double advantage of preserving testicular endocrine function and maintaining the possibility of natural fatherhood.     

Cellular localization of the Mn2+-dependent adenylyl cyclase in the human testis

An examination of the activity of the Mn2+-dependent adenylyl cyclase (AC) in fine needle biopsies from human testes was made. Simultaneously the DNA distribution patterns in suspensions of testicular cells derived from the same patients have been determined. The DNA distribution patterns were estimated by microflow fluorimetry (MFF) after straining with fluorochrome (ethidium bromide). Thus, AC activity could be assessed and correlated with the relative number of haploid (1C = spermatids), diploid (2C = spermatogonia and testicular somatic cells), and tetraploid (4C = primary spermatocytes) cells. Testicular Mn2+-dependent AC activities varied between 0 and 8.4 pmol cyclic adenosine monophosphate (cAMP)/mg protein/min and were highly correlated with the contents of haploid (1C) germ cells (spermatids) (r = 0.62, p less than 0.01). There was no correlation between Mn2+-dependent AC activity and diploid or tetraploid cells. This indicates that the Mn2+-dependent AC activity in the human testis, like in the rat and mouse, may be exclusively localized to haploid germ cells. An inverse correlation between plasma FSH and Mn2+-dependent AC activities indicated reduced inhibin secretion in situations where the Sertoli cells did not maintain the testicular germ cell production.     

Reproductive aging in the Brown Norway rat is characterized by accelerated germ cell apoptosis and is not altered by luteinizing hormone replacement.

Reproductive aging in the male Brown Norway (BN) rat is characterized by decreased Leydig cell steroidogenesis associated with seminiferous tubule dysfunction. This could be a result of a combination of a primary testicular defect and a secondary hypothalamic pituitary dysfunction. In the present study, we determined in the BN rat whether germ cell loss occurred via apoptosis. We then defined the age of onset of Leydig cell dysfunction and germ cell loss and examined whether chronic luteinizing hormone (LH) replacement would delay or prevent reproductive aging. Plasma hormone levels, testicular sperm concentrations, and germ cell apoptosis were studied in 6, 9, 12, 15, 18, and 21-month-old BN rats. Beginning at 15 months, testicular weight, sperm concentration, total sperm counts, plasma testosterone, LH, and inhibin decreased, whereas the proportion of regressed testes and plasma follicle-stimulating hormone (FSH) levels increased with aging. Accelerated germ cell apoptosis involving spermatogonia, preleptotene and pachytene spermatocytes, and spermatids was evident in some tubules of the relatively normal testes from 21-month-old rats. In the regressed testes, complete cessation of spermatogenesis occurred. The apoptotic index was higher in the testes of old (21-month-old) rats in particular at stages XII-XIV when compared with younger animals. Chronic LH replacement (0.5 microg i.p. twice per day) administered to 15-month-old BN rats for 6 months did not alter plasma hormone levels, testes weight, sperm concentration or content, or the germ cell apoptotic index. In the control group, 3 out of 10 testes were regressed, whereas in the LH-replaced group, only 1 out of 12 testes was regressed. We show in this study that early reproductive aging in the BN rat began at around 15 months. Germ cell loss associated with aging occurs via apoptosis. Replacement therapy with LH for 6 months does not decrease or delay the testicular dysfunction associated with aging. It is unlikely that hypothalamic-pituitary dysregulation is the major cause of testicular aging.     

Azoospermia and Sertoli‐cell‐only syndrome: hypoxia in the sperm production site due to impairment in venous drainage of male reproductive system

Sertoli‐cell‐only (SCO) syndrome, or germ cell aplasia, is diagnosed on testicular biopsy when germ cells are seen to be absent without histological impairment of Sertoli or Leydig cells. It is considered a situation of irreversible infertility. Recent studies have shown that varicocele, a bilateral disease, causes hypoxia in the testicular microcirculation. Destruction of one‐way valves in the internal spermatic veins (ISV) elevates hydrostatic pressure in the testicular venules, exceeding the pressure in the arteriolar system. The positive pressure gradient between arterial and venous system is reversed, causing hypoxia in the sperm production site. Sperm production deteriorates gradually, progressing to azoospermia. Our prediction was that, if genetic problems are excluded, SCO may be the final stage of longstanding hypoxia which deteriorates sperm production in a progressive process over time. This would indicate that SCO is not always an independent disease entity, but may represent deterioration of the testicular parenchyma beyond azoospermia. Our prediction is confirmed by histology of the seminiferous tubules demonstrating that SCO is associated with extensive degenerative ischaemic changes and destruction of the normal architecture of the sperm production site. Adequate treatment of bilateral varicocele by microsurgery or by selective sclerotherapy of the ISV resumes, at least partially, the flow of oxygenated blood to the sperm production site and restored sperm production in 4 out of 10 patients. Based on our findings the following statements can be made: (i) SCO may be related in part of the cases to persistent, longstanding testicular parenchymal hypoxia; (ii) germ cells may still exist in other areas of the testicular parenchyma; and (iii) if genetic problems are excluded, adequate correction of the hypoxia may restore very limited sperm production in some patients.     

大鼠睾丸间质细胞的原代培养、鉴定与功能监测

目的:采用改良方法对大鼠睾丸间质细胞进行分离、纯化和原代培养,以得到更高纯度和稳定的间质细胞原代培养体系。方法:采用酶消化法分离大鼠睾丸间质细胞,再用Percoll连续密度梯度离心除去生精细胞、支持细胞等杂细胞,实现进一步纯化;用3β-HSD特异性染色法鉴定间质细胞,同时采用放射免疫法测定间质细胞睾酮分泌活性。结果:培养的间质细胞纯度达到95%以上,每个睾丸可获取间质细胞约1×106个;通过3β-HSD特异性染色鉴定,该间质细胞胞质呈蓝黑色,而且细胞具有分泌睾酮的活性。结论:酶消化后以Percoll连续密度梯度离心可分离得到高纯度且具有睾酮分泌活性的间质细胞,操作简单易行,实验方法稳定。     

多氯联苯的雄性生殖毒性研究进展

多氯联苯(PCBs)是一类环境中广泛存在的具有雌激素样效应的持久性有机污染物,它对男性生殖的损害正越来越受到关注。研究表明睾丸组织中多种不同类型的细胞暴露于PCBs能产生不同的毒性效应。本文就近年来PCBs暴露对睾丸生精细胞、支持细胞、间质细胞以及母体暴露后雄性子代的毒性效应研究进行综述。建议根据目前男性生殖流行病学的调查结果进行深入的机制研究,同时睾丸支持细胞的胞间连接可作为PCBs睾丸毒性研究的突破方向之一。     

Histological alterations in Leydig cells and macrophages in azoospermic men

The study aimed to compare the histological features of Leydig cells and macrophages in the testicular interstitium of obstructive versus nonobstructive azoospermia. Thirty‐nine azoospermic men undergoing testicular sperm extraction during intracytoplasmic sperm injection were allocated into obstructive azoospermia group (GI) and nonobstructive azoospermia group (GII) which was subdivided into Sertoli cell‐only syndrome (GIIA), germ cell arrest (GIIB) and hypospermatogenesis (GIIC) subgroups. Serum LH, FSH and testosterone levels were measured. Ultrastructural changes and the mean number of CD68‐positive cells were estimated in the different groups. In GIIA, Leydig cells' processes came in contact with macrophages and showed smooth endoplasmic reticulum dilatation. In GIIB, Leydig cells showed apoptotic changes. Macrophages were commonly encountered in their vicinity demonstrating large number of lysosomes. In GIIC, Leydig cells showed euchromatic nuclei. Macrophages showed expulsion of their lysosomal contents in the interstitium surrounded by apoptotic bodies. The mean count of total CD68‐positive macrophages was higher in cases of obstructive azoospermia with nonsignificant differences compared to nonobstructive azoospermia groups. Significant increase in FSH level was detected in GIIA compared to GI. It is concluded that structural interactions might take place between Leydig cells and macrophages in the interstitial tissue of azoospermic men.     

Local regulation of Leydig cells by the seminiferous tubules. Effect of short-term cryptorchidism

Unilateral cryptorchism was induced in adult rats for 24 h, and its effect on testicular morphology and intratesticular testosterone concentration after hCG-stimulation were studied. In seminiferous, tubules from abdominal testes an increased number of degenerating germ cells was noted in stages XIV-III of the spermatogenic cycle and Sertoli cells contained an increased amount of lipid droplets in stages XIV-VIII. However, germ cells and Sertoli cells from tubules at other stages of the cycle appeared unaffected. In scrotal testes the size of peritubular Leydig cells varied in phase with the spermatogenic cycle. The largest cells were found adjacent to stage VII-VIII and the smallest adjacent to stage XI-XII. In abdominal testes no stage-dependent variation in the size of peritubular Leydig cells was seen. Perivascular Leydig cells were of equal size in abdominal and scrotal testes. The testicular testosterone concentration following stimulation with a low dose of hCG was significantly lower in abdominal testes. It is suggested that the seminiferous tubules locally modulate Leydig cell function and that the stage specific stimulatory influence from stage VII-VIII is rapidly lost during experimental cryptorchidism.     

睾丸扭转后生精细胞凋亡与iBOS基因表达

本文研究了睾丸扭转复位后生精细胞凋亡与iBOS基因表达的关系。采用大鼠建立左侧睾丸扭转复位模型（720,2h)。用TUNEL法和免疫组化SP法分别检测扭转复位后第五天生精细胞凋亡和iBOS基因表达。研究发现凋亡主要见于染色质降解的生精细胞（初级精母细胞和圆形精子细胞）。间质细胞和支持细胞未见凋亡发生。iBOS表达见于各级生精细胞,在染色质降解的生精细胞（即凋亡细胞）强表达。本文研究表明睾丸扭转复位后生精细胞凋亡增加与iBOS基因表达密切相关。睾丸局部NO生成异常可能是生精细胞凋亡增加的原因之一。     

Hepatocyte growth factor-modulated rat Leydig cell functions

Hepatocyte growth factor (HGF) regulates many cellular functions acting through c-Met, its specific tyrosine kinase receptor. We previously reported that in prepuberal rats HGF is secreted by the peritubular myoid cells during the entire postnatal testicular development and by the Sertoli cells only at puberty. We have also demonstrated that germ cells at different stages of development express c-Met and that HGF modulates germ cell proliferation and apoptosis. In the present article, we extend our study to the interstitial compartment of the testis and demonstrate that the c-Met protein is present on Leydig cells. The receptor is functionally active as demonstrated by the detected effects of HGF. We report in this article that HGF significantly increases the amount of testosterone secreted by the Leydig cells and decreases the number of Leydig cells undergoing apoptosis. The antiapoptotic effect of HGF is mediated by caspase-3 activity because the amount of the active fragment of the enzyme is decreased in Leydig cells cultured in the presence of HGF. However, treatment with the growth factor does not modify the expression levels of caspase-3 mRNA. These data indicate that HGF regulates the functional activities of Leydig cells. Interestingly, the steroidogenetic activity of the cells is increased by HGF in cultured explants of testicular tissues as well as the antiapoptotic effect of HGF. Therefore, our data indicate that HGF has a crucial role in the regulation of male fertility.     

The ameliorative effects of Ginkgo biloba on apoptosis,LH‐R expression and sperm morphology anomaly in testicular torsion and detorsion

Torsion/detorsion (T/D) induces testicular damages in both germinal epithelial and interstitial tissues. Ginkgo biloba extract (GbE) exerts antioxidant and free radical scavenger. We investigated the effect of GbE on testicular tissues, Leydig and sperm cells in rats injured with T/D. Twenty‐eight Wistar albino rats were randomly assigned into four groups (Control, GbE, Treatment: T/D+GbE, T/D). T/D performed to the rats in torsion, treatment received GbE (50 mg/kg) 1 hr before T/D, GbE group received only GbE (50 mg/kg) and control was defined as sham group. After T/D, the testes along with epididymis were removed and processed. LH‐R expression, apoptosis, sperm morphology and histopathological damage scores were determined for each group. Testicular T/D caused significant increases in apoptosis and sperm morphology anomaly, and a significant decrease in Johnsen's testicular biopsy scores, LH‐R expression of Leydig cell and normal sperm cell count. GbE ameliorated testicular histopathology and caused significant increases in LH‐R expression, normal sperm cell count in the treated and particularly GbE group. Consequently, GbE may prevent testicular injury and enhance Leydig and sperm cell activity following both T/D and normal situation owing to its antioxidant, anti‐apoptotic, free radical scavenger and anti‐inflammatory effects.     

Effects of supplementation with impuberal or adult testicular protein extracts on genital tract and testicular histology as well as hormonal levels in adult busulfan treated rats

24 adult Wistar rats received one SC injection of busulfan (10 mg/kg BW) on day 0. They were injected daily from day 1 to day 10 either with BSA (1 and 2 mg/rat, n = 5 respectively), with acetonic extract of adult ram testicular cytosol (2 mg/rat, n = 10) or with acetonic extract of impuberal calf testicular cytosol (2 mg/rat, n = 4). 10 animals served as control. Animals were killed on day 17. Busulfan treatment induced decrease of total volumes of intertubular tissue and of Leydig cells per testis, of accessory glands, and of germ cells from type A spermatogonia to zygotene spermatocytes. Supplementation with adult testicular extract did not modify accessory glands but increased Leydig cell total volume, individual cellular and nuclear areas and Sertoli cell nuclear areas. It decreased further the germ cells from A spermatogonia to zygotene primary spermatocytes. Supplementation with impuberal testicular extract did not modify accessory glands, Leydig cell total volume, individual cellular and nuclear areas or Sertoli cell nuclear area. It increased the germ cells from A spermatogonia to zygotene primary spermatocytes to values intermediate between those of control and busulfan treated rats.