从江香猪生精上皮周期及睾丸发育的形态学分析

试验旨在探究初情期前后生精上皮周期差异及睾丸发育过程中的形态学变化。通过测定15、30、60和90 d睾丸相关指数，结合睾丸组织形态学特征，判断香猪初情期，划分从江香猪生精上皮周期。结果显示，30 d的睾丸指数较15 d极显著升高（P<0.01），睾丸重、长轴及短轴的增长率分别为298.05%、66.42%和65.45%，60和90 d两个阶段睾丸重增长率相对稳定。形态学观察表明，从江香猪30 d时生精小管出现游离精子，完成第一次生精并进入初情期；与15 d相比，30 d生精小管面积和生精上皮厚度极显著增加（P<0.01），增长率分别为136.12%和40.19%，在60和90 d均处于稳定增长状态。睾丸细胞数统计显示，日龄增加不影响支持细胞（setoli cells，SC）数量（P>0.05），而30 d生殖细胞数（germ cells，GC）较15 d极显著增加（P<0.01）。相关分析结果发现，生殖细胞数量增加与生精小管面积增大、生精上皮厚度变化之间呈明显正相关（r=0.994；0.96）。根据生殖细胞组合形式差异，将初情期前后生精上皮分为3和8个阶段。初情期前生殖细胞以第一次减数分裂前期为主，A、B型精原细胞、SC、初级精母细胞（primary spermatocyte，Ps）、前细线期（preleptotene，PI）、细线期（leptotene，L）等生殖细胞在初情期前后生精上皮中均存在，而圆形精子（round spermatids，R）、延伸精子（elongating spermatid，E）、精子细胞（spermatozoa，S）仅存在于初情期后的生精上皮。本研究结果表明，从江香猪30 d初情，睾丸发育以生殖细胞和生精小管面积的迅速增加为主，该结果对从江香猪早熟性状挖掘、种猪选育及开发利用等有重要的指导意义。     

Effects of the GnRH antagonist acyline on the testis of the domestic cat (Felis catus)

The aim of this study was to describe the effects of a single dose of the gonadotrophin releasing hormone (GnRH) antagonist acyline on testicular characteristics of the domestic cat. Twelve mature cats were orchidectomised unilaterally (right testis) on Day -7 (n=7) or Day 15 (n=5). On Day 0, 330 μg/kg acyline was administered s.c. to all the animals. Left orchidectomy was carried out on Day 15 (n=2), Day 30 (n=4) and Day 60 (n=6). Sperm were recovered from the epididymis and the testes were evaluated grossly, histologically and immunohistochemically. Significant differences (P<0.05) were found between days for epididymal sperm motility, vigor, abnormal morphology, germinal epithelium height, spermatocytes, spermatids, spermatozoa, lumen and cellular debris. Conversely, no significant differences were found for gross testicular and tubular characteristics, spermatogonia, Sertoli and Leydig cells and intertubular compartments. It was concluded that a single dose of acyline reversibly impaired spermiogenesis, spermatocytogenesis and sperm motility for 2 weeks.     

Inhibitive effects of quinestrol on male testes in Mongolian gerbils (Meriones unguiculatus)

The current study evaluated effects of quinestrol on oxidative stress and abnormal spermatogenesis for male Mongolian gerbils. Gerbils were randomly divided into multi-dose treated, single-dose treated, control groups. At 15 days after treatment antioxidant enzymes (SOD, GSH-Px) activities and T-AOC were decreased whereas the MDA concentration was significantly increased, testicular weight and seminiferous tubular areas decreased, germ cells were rarefied and showed irregular distribution in seminiferous tubules, apoptosis was pronounced among spermatocytes and spermatids, the number of dead and abnormal acrosomes of spermatozoa increased significantly in quinestrol treated groups. At 30 days following treatment the testicular histopathological changes were more severe, sperm quality and antioxidant capacity continued to decline, and multi-dose treatment produced more damage to gerbils testes compared with single-dose treatment. The physiological indicators were recovered by 60 days of treatment withdrawal. The results showed oxidative stress induced by quinestrol in relation to abnormal spermatogenesis.     

Embryo production by intracytoplasmic injection of sperm retrieved from Meishan neonatal testicular tissue cryopreserved and grafted into nude mice

Testicular xenografting, combined with cryopreservation can assist conservation of the genetic diversity of indigenous pigs by salvaging germ cells from their neonatal testes. Using Meishan male piglets as an example, we examined whether testicular tissue would acquire the ability to produce sperm after cryopreservation and grafting into nude mice (MS group). For comparison, testicular tissue from neonatal Western crossbreed male piglets was used (WC group). Sixty days after xenografting (day 0 = grafting), MS grafts had already developed seminiferous tubules containing sperm, whereas in the WC grafts, sperm first appeared on day 120. The proportion of tubules containing spermatids and sperm was higher in the MS group than in the WC group between days 90 and 120. Moreover, in vitro‐matured porcine oocytes injected with a single sperm obtained from the MS group on day 180 developed to the blastocyst stage. The blastocyst formation rate after injection of the xenogeneic sperm was 14.6%, whereas the ratio in the absence of such injection (attributable to parthenogenesis) was 6.7%. Thus, cryopreserved Meishan testicular tissue acquired spermatogenic activity in host mice 60 days earlier than Western crossbreed tissue. Such xenogeneic sperm are likely capable of generating blastocysts in vitro.     

Analysis of various antigens in golden hamster testis by monoclonal antibodies.

A total of 38 hybridomas producing monoclonal antibodies (mAbs) was established by immunizing BALB/c mice with extracts of the golden hamster testis. Six mAbs stained the acrosome of developing spermatids by immunofluorescence. Two mAbs (1A11 and 4D8) reacted with spermatid components other than acrosome. The mAbs 1C9 and 4D3 recognized a 103 kilodalton (kDa) protein on immunoblots, and were reactive to spermatocytes and early spermatids, but not to late spermatids and spermatozoa. This finding suggests that the protein functions for meiosis or early spermiogenesis. Four mAbs (3G2, 2E5, 2G3, and 3F10) stained all stages of spermatogenic cells. The remaining 24 mAbs showed a positive reaction to the basement membrane of the seminiferous tubule. Two of them, 3D6 and 3E5, recognized approximately 150 kDa major proteins, indicating that the antigen is an extracellular matrix.     

野外采集牦牛睾丸组织的冷冻保存及其生精细胞的复苏培养研究

采用玻璃化冷冻方法对野外采集的牦牛睾丸组织进行冷冻,通过HE(hematoxylin-eosin)染色分析发现玻璃化冷冻后的牦牛睾丸组织曲细精管结构保存较完好,曲细精管可见大量形态完好的各类生精细胞。采用台盼蓝染色检测细胞活率,发现冷冻复苏后细胞活率可达80.20%。分别通过生精细胞和精原干细胞标志蛋白DDX4和GFRA1免疫荧光染色发现复苏后培养14天后的生精细胞和精原干细胞的数量明显减少。通过RT-qPCR对复苏后不同实验处理组牦牛睾丸细胞标志基因的表达分析,发现培养30天的生精细胞中的精原干细胞标志基因Thy1和UCHL1的表达量显著增高。因此,玻璃化冷冻保存的牦牛睾丸组织中曲细精管及其生精细胞得到了较好的保护,该方法对于其他哺乳动物生精细胞的长久有效保存具有重要的参考价值。     

Testicular fine needle aspiration cytology from a stallion with testicular degeneration after external genitalia trauma

A seven-year-old Quarter Horse had a serious external genitalia trauma with severe swelling of ventrum, penis, prepuce and scrotum after falling over a fence. Appropriated treatment was rapidly started after clinical examination. During recovery period, the spermatogenesis assess by semen evaluation was not possible due to stallion's inability to ejaculate. Therefore, for testicular evaluation fine needle aspiration cytology (FNAC) was performed. The first FNAC showed a deviation of germ cell line towards immature cells, mainly by primary spermatocytes (59.5%) with very few late spermatids and spermatozoa (2.5% each), and an increased Sertoli cells/germ cells ratio (478/100), which characterized testicular degeneration. One month after the first FNAC, the second exam presented a drastic decrease of Sertoli cells/germ cells ratio (7/100) and marked increase of mature cell number, specially by early and late spermatids (50% and 24.5%, respectively). In this case, the results of both FNAC could demonstrate a partial recovery of spermatogenesis activity. Two months later, the stallion had mated two mares successfully and they became pregnant. In conclusion, the adequate treatment allowed a complete recovery of the stallion's reproductive function, and since semen collection was impossible during treatment, testicular FNAC showed to be an efficient diagnostic method for evaluating acute damage in the spermatogenesis.     

Effects of Intratesticular Injection of 70% Glycerin on Stallions

The removal of endogenous germ cells of recipient stallions is a key step to produce donor germ cell-derived sperm using the germ cell transplantation technique. Six Thoroughbred stallions were divided into a treatment (n = 3) and a control group (n = 3), and 70% glycerin (1, 2, 3-trihydroxypropane, 40 mL per testis) or phosphate-buffered saline, respectively, was locally injected into testes. General semen evaluation, libido, and testicular volume were performed weekly from 3 weeks before to 10 weeks after treatment. The number of round germ cells in the ejaculate was counted using a hemocytometer. The hematoxylin and eosin staining was performed on the cross sections of testicular tissue obtained 11th week of treatment. Plasma testosterone levels in blood collected weekly were measured using a colorimetric competitive enzyme immunoassay kit. The sperm number was significantly lower than that of the control group at 5 and 10 weeks after glycerin injection. No differences in the status of spermatogenesis in the cross sections of seminiferous tubules and testicular volume were found between the two groups. The 70% glycerin-treated stallions had reduced total and progressively motile sperm and exhibited a significantly higher population of round germ cells in the ejaculate. Testosterone levels, testicular volumes, and libido of stallions were not significantly different between the groups. In conclusion, although intratesticular injection of 70% glycerin may have caused disassociation of some germ cells in the seminiferous tubules for several weeks, it did not significantly ablate germ cells in the tubules at 11 week in stallions.     

Acute and Chronic Effects of a Contraceptive Compound RTI‐4587‐073(l) on Testicular Histology and Endocrine Function in Miniature Horse Stallions

The objective of this study was to evaluate acute endocrine effects as well as histological changes in testicular parenchyma induced by the contraceptive compound RTI‐4587‐073(l). Six miniature stallions were used in this experiment. The treatment group (n = 3) received one oral dose of 12.5 mg/kg of RTI‐4587‐073(l), and the control group (n = 3) received placebo only. The stallions' baseline parameters (semen, testicular dimensions, endocrine values) were collected and recorded for 5 weeks before treatment and for 6 weeks after treatment. Multiple blood samples were collected for endocrine analysis. Testicular biopsies were obtained before treatment, 1 day after treatment and every other week after treatment. Ultrasound exams were performed to monitor the dimensions of the stallions' testes. All stallions were castrated 6 weeks after treatment. Sperm numbers, motility and percentage of morphologically normal sperm decreased (p < 0.05), while the number of immature germ cells increased in ejaculates from treated animals (p < 0.05). Serum concentrations of inhibin and follicle‐stimulating hormone did not change. Testosterone concentrations initially transiently decreased (p < 0.05) after administration of RTI‐4587‐073(l), and increased several days later (p < 0.05). Testicular content of testosterone and estradiol 17‐β was lower in treated stallions than in control stallions on Day 1 after treatment (p < 0.05). Severe disorganization of the seminiferous tubules, significant loss of immature germ cells and complete depletion of elongated spermatids were observed in testicular biopsies obtained from treated stallions 1 day, 2 and 4 weeks after treatment. These changes were still present in the testicular samples taken from treated stallions after castration. The results of this study confirmed that RTI‐4587‐073(l) has antispermatogenic effects in stallions. Furthermore, we concluded that this compound causes acute sloughing of immature germ cells from the seminiferous tubules. RTI‐4587‐073(l) has significant but transient effects on Leydig cell function in stallions.     

Effect of dietary selenium and vitamin E on spermatogenic development in boars

An experiment involving a total of 61 crossbred boars evaluated the effects of dietary Se and vitamin E on spermatogenic development at various stages of sexual development and the prostaglandin F2alpha (PGF2alpha) content in the seminal vesicle and prostate glands at 18 mo of age. The experiment from 5.4 to 9 mo of age was conducted as a 2 x 2 factorial in a randomized complete block design. Dietary Se at 0 or .5 ppm was the first factor and vitamin E at 0 or 220 IU/kg diet was the second. From 9 to 18 mo of age, a group of sexually active and inactive boars was a third factor. Treatment diets were fed from weaning (28 d of age) to the end of the experiment. Three boars per treatment group at 5.4 (105 kg BW), 6.2 (130 kg BW), and 9.0 (150 kg BW) mo of age were killed and the testes collected. From 9 to 18 mo of age, three boars from each dietary treatment group were used for semen collection, and another set of three to four boars from each treatment group remained sexually inactive. At 18 mo, both sets of boars were killed and their testes, prostates, and seminal vesicles were collected. The testis at each age was evaluated for sperm reserve numbers and germ and Sertoli cell populations. At 5.4 or 6.2 mo of age, testicular sperm reserves were not affected by dietary Se (P > .15), at 9.0 mo of age there was a trend for a higher (P < .10) number of sperm reserves, and by 18 mo of age the Se-fed boars had higher (P < .01) numbers of sperm reserves. Vitamin E had no effect (P > .15) on testicular sperm reserves at any age period. Boars fed dietary Se had a greater number of Sertoli cells (P < .01) and round spermatids (P < .01) at 6.2 mo of age, but by 18 mo of age the boars fed Se had more Sertoli cells (P < .05), more secondary spermatocytes (P < .01), and more round spermatids (P < .05). Vitamin E did not affect Sertoli or germ cell populations at the various ages. Boars at 18 mo of age had lower PGF2alpha concentrations in the prostate (P < .05) and seminal vesicles (P < .01) when vitamin E was fed, whereas Se had no effect. Sexually active boars had lower PGF2alpha concentrations in the seminal vesicles (P < .01) than sexually inactive boars, but there was no effect (P > .15) of sexual activity on the number of Sertoli cells, primary or secondary spermatocytes, or round spermatids. Our results indicate that Se has a role in establishing the number of boar spermatozoal reserves and Sertoli cells, whereas supplemental vitamin E did not affect these criteria.     

Full-term development of offspring using round spermatids produced ectopically from fetal male germ cells

The continuous production of mammalian sperm is maintained by the proliferation and differentiation of spermatogonial stem cells, which originate from primordial germ cells in the early embryo. Previously, we reported that the transplantation of fetal male gonadal tissue into the recipient testis was effective obtaining functional sperm. This transplantation technique is a promising new approach for the preservation of testicular function in a mutant animal with embryonic lethality. In the present study, we examined whether spermatogenesis from fetal male germ cells is induced under ectopic conditions in male and female recipients. Nine to 10 weeks after the transplantation of male gonads prepared from embryos at 12.5 or 16.5 days post gestation, male germ cell differentiation occurred under the skin of male and female recipient nude mice. Histological analyses revealed that grafted gonads contained haploid germ cells such as round or elongated spermatids. Furthermore, we succeeded in obtaining normal progeny by injecting the ectopically produced round spermatids into the cytoplasm of oocytes, even when the male germ cells had been generated in female recipients. These results indicate that the transplantation of fetal male gonads under the skin of recipient mice is a useful technique for obtaining functional male gametes.     

2-Bromopropane induced germ cell apoptosis during spermatogenesis in male rat

2-Bromopropane (2-BP) causes testicular toxicity in humans and rats. However, the germ cell degeneration of testicular toxicity by 2-BP has not been understood. 2-BP at doses of 135, 405, and 1,355 mg/kg/day was daily injected subcutaneously into Sprague-Dawley rats for 28 days. At the dose of 1,355 mg/kg/day, 2-BP significantly decreased the weights of body and testes, eipididymis, seminal vesicle, and prostate, as well as daily sperm production. Atrophy of seminiferous tubules accompanied with degeneration of germ cells such as spermatogonia, spermatocytes, and elongated spermatids was observed in the testes of rats exposed to the 405 mg/kg/day and 1,355 mg/kg/day of 2-BP. TUNEL-positive germ cells were appeared in the 405 and 1,355 mg/kg/day of 2-BP-treated groups. In addition, ultrastructure alterations of apoptotic germ cells were observed by the electron microscopy study. Dead elongated spermatids were observed at 1,355 mg/kg/day after 28 days exposure. These results suggest that 2-BP impair spermatogenesis may result from apoptotic germ cell death.     

Synthesis, processing, and subcellular localization of mouse ADAM3 during spermatogenesis and epididymal sperm transport

To elucidate synthesis, processing, and subcellular localization of mouse ADAM3 (cyritestin) during spermatogenesis and epididymal sperm transport, we carried out immunoblotting and immunohistochemical analysis of testicular germ cells, and epididymal and vas deferens sperm, using affinity-purified anti-ADAM3 antibody. ADAM3 was initially synthesized as a 110-kDa precursor in round spermatids, and the precursor was then processed into a 42-kDa mature protein during the sperm transport into and/or once in the epididymis. The mature ADAM3 was localized on the anterior part of capacitated sperm heads and was rapidly removed from the head region during the calcium ionophore A23187-induced acrosome reaction. These results demonstrate that the mature form of ADAM3 is involved in the binding of sperm to the egg zona pellucida, not in the membrane fusion between sperm and egg.     

Relationship of absolute numbers of Sertoli cells to testicular size and spermatogenesis in young beef bulls

Testes were obtained from 34 Hereford or Angus bulls at about 1.5 yr of age and were used to investigate the relationship between the absolute number of Sertoli cells vs testicular size and daily spermatozoal production (DSP). Quantitative determination of DSP was based upon enumeration of elongated spermatids in testicular homogenates. The ratio of step 8 spermatids to Sertoli cells (S:SC) was established by direct counts of these cells in each of 20 round stage VIII seminiferous tubular cross sections for each bull. The number of Sertoli cells per paired testes was calculated as (total spermatids divided by S:SC)/.394, where total spermatids equalled the number of homogenization-resistant spermatids. The factor of .394 adjusted for the fact that the latter cells are present for only 39.4% of the spermatogenic cycle. All data were subjected to simple linear and second-order regression analyses. A positive linear relationship (P less than .005) was found between testicular weight (Y, in grams) and the absolute number of Sertoli cells per paired testes (X, in billions), which was characterized by the equation Y = 315.2 + 10.74X and a coefficient of correlation (r) of .56 (P less than .01). A similar relationship was observed between DSP (Y, in billions) and Sertoli cell numbers (X, in billions). This was characterized by the equation Y = 1.36 + .222X (P less than .005) and a coefficient of correlation of .70 (P less than .01). Daily sperm production was unrelated to the S:SC ratio (P greater than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

ART3抑制剂3-MBA对小鼠睾丸生精功能的影响

旨在探究ADP-核糖基转移酶3(ADP-ribosyl transferase 3,ART3)调控精子发生机制,为改善精液品质,提高家畜繁殖性能提供理论依据。本试验设计了3个ART3抑制剂3-甲氧基苯甲酰胺(3-methoxybenzamide, 3-MBA)浓度梯度(0.302、0.906和1.510 mg·mL^-1),分别对6～8周龄小鼠进行睾丸注射,并于注射后3 h、6 h、12 h、1 d、2 d、3 d和5 d采集小鼠睾丸和附睾组织,将睾丸组织制成石蜡切片进行HE染色,并对附睾尾精子进行动力学和形态学分析。结果发现,0.302 mg·mL^-13-MBA浓度组于注射后3 d小鼠睾丸曲细精管内空泡面积达到最大化,生精细胞减少,且排布散乱不规则,注射后5 d空泡面积减小,生精细胞有恢复趋势,而0.906和1.510 mg·mL^-1浓度组于注射后5 d空泡面积最大化,曲细精管出现空管现象;3个剂量组小鼠附睾尾精子密度、活力及前向运动精子均呈时间依赖性降低,畸形精子随时间推移逐渐增加,且精子尾部出现断裂、弯折和卷曲等异常...     

Distribution of the sex chromosome during mouse spermatogenesis in testis tissue sections

During mammalian spermatogenesis, spermatogenic cells undergo mitotic division and are subsequently divided into haploid spermatids by meiotic division, but the dynamics of sex chromosomes during spermatogenesis are unclear in vivo. To gain insight into the distribution of sex chromosomes in the testis, we examined the localization of sex chromosomes before and after meiosis in mouse testis sections. Here, we developed a method of fluorescence in situ hybridization (FISH) using specific probes for the X and Y chromosomes to obtain their positional information in histological testis sections. FISH analysis revealed the sex chromosomal position during spermatogenesis in each stage of seminiferous epithelia and in each spermatogenic cell. In the spermatogonia and leptotene spermatocytes, sex chromosomes were distantly positioned in the cell. In the zygotene and pachytene spermatocytes at prophase I, X and Y chromosomes had a random distribution. After meiosis, the X and Y spermatids were random in every seminiferous epithelium. We also detected aneuploidy of sex chromosomes in spermatogenic cells using our developed FISH analysis. Our results provide further insight into the distribution of sex chromosomes during spermatogenesis, which could help to elucidate a specific difference between X and Y spermatids and sex chromosome-specific behavior.     

Effect of extended photoperiod on the spermatogenic activity of chicken-pheasant hybrids

1. Males of chicken-pheasant hybrids and non-breeding pheasants were exposed to photoperiods of 10 or 20 h/d to test the effect of light on spermatogenic activity. 2. Testicular weights of hybrids and pheasants exposed to 10 h/d were similar and extending the photoperiod did not increase this in hybrids, although it caused a 48-fold increase, and complete recovery of spermatogenic activity, in pheasant. 3. Extending the photoperiod caused an increase in the number of primary spermatocytes and a corresponding decrease in the number of spermatogonia in hybrids, however, stages beyond primary spermatocytes were not present. This suggests that the stimulus of extending the photoperiod, while sufficient to induce meiosis in existing germ cells, is not enough to effect proliferative bursts or to overcome the meiotic arrest in the hybrids.     

Seasonal change of circulating leptin associated with testicular activities of the wild ground squirrels (Citellus dauricus)

The purpose of this study was to explore the variations in the circulating leptin concentrations of the wild ground squirrels in relation to seasonal changes in testicular activities. Hematoxylin-eosin staining showed all types of elongated spermatids and spermatogenic cells existed in the testis in April, while the primary spermatocytes and spermatogonia were most advanced stages of germ cells in June. In addition, the primary spermatocytes, secondary spermatocytes, and spermatogonia were most advanced stages of germ cells in September. The highest circulating leptin concentration was consistent with the maximum body weight results from accumulation of adipose tissue in September. The mRNA expression level of leptin receptor (Ob-R) and STAT3 was lowest in June, raised in September, and remained increased in April. Ob-R and STAT3 were stronger staining in the Leydig cells in July. Moreover, the concentrations of testosterone (T) showed the maximum values in April, the minimum values in June, and significant increases in September. Furthermore, it is worth noting that the levels of T increased with the mRNA levels of Ob-R, STAT3, StAR, and testicular steroidogenic enzymes (3β-HSD, P450c17, and P450scc). Moreover, RNA-seq analyses of testis during the different periods showed that a total of 4209 genes were differentially expressed genes (DEGs); further analysis revealed that DEGs related with the Jak/STAT pathways and reproduction were altered. Taken together, the results suggested that the leptin regulated testicular function through the Jak/STAT pathways and testicular steroidogenic factor expressions.     

Seasonal changes in spermatogenesis and testicular steroidogenesis in wild male raccoon dogs (Nyctereutes procynoides)

Testes of 15 wild adult male raccoon dogs (Nyctereutes procynoides) obtained from September 2000 to April 2001 were studied to clarify seasonal changes in spermatogenesis and testicular steroidogenesis. There were marked seasonal variations in the testis weight and size with values relatively low in September and highest in March. Spermatogonia and primary spermatocytes were observed in September, while spermatogonia, spermatocytes and round spermatids were present in January, and all types of spermatogenic cells including mature spermatozoa were found in the mating season (February and March). The number of spermatogenic cells reached their peak values in February and March. In addition, steroidogenic enzymes were immunolocalized using polyclonal antisera raised against bovine adrenal cholesterol side-chain cleavage cytochrome P450 (P450scc), human placental 3beta-hydroxysteroid dehydrogenase (3 betaHSD), porcine testicular 17alpha-hydroxylase cytochrome P450 (P450c17), and human placental aromatase cytochrome P450 (P450arom). P450scc and P450c17 were identified in Leydig cells and spermatids in February, whereas these enzymes were present only in Leydig cells in September. 3betaHSD was found in Leydig cells in September and February with more intense staining in February. The localization of P450arom changed seasonally: no immunostaining in September; more extensive immunostaining in Leydig cells, Sertoli cells, and elongating spermatids in February. These results suggest that seasonal changes in the testis weight and size of wild male raccoon dogs are correlated with changes in spermatogenesis. Seasonal changes in testicular steroidogenesis suggest that the synthesis of androgen and estrogen reaches its peak in the mating season.