Reproduction of the male eastern pipistrelle, Pipistrellus subflavus, in the north-eastern United States

The major reproductive events in the male eastern pipistrelle, are similar to those of other hibernating vespertilionids. The eastern pipistrelle stores epididymal spermatozoa throughout hibernation, a time when the testes are involuted but accessory gland activity is maintained. However, this species differs from others in that epididymal and testicular spermatozoa persist longer and the weights of the accessory glands are not strongly differentiated between winter and spring/summer. It is suggested that the reproductive period is extended in this species as a function of a more prolonged period of hibernation, resulting in only a brief period of sexual quiescence in mid-summer. The eastern pipistrelle (Pipistrellus subflavus) resembles the canyon bat (P. hesperus) in that some testicular spermatozoa persist during winter. Many aspects of the reproductive anatomy and chronology of these two species are similar; however, eastern pipistrelles apparently lack a seminal vesicle and possess a distinctly different baculum.     

Seasonal timing of sperm production in roe deer: interrelationship among changes in ejaculate parameters,morphology and function of testis and accessory glands

Roe deer are seasonal breeders with a short rutting season from mid-July to mid-August. The seasonality of reproductive activity in males is associated with cyclic changes between growth and involution of both testes and the accessory sex glands. This study characterizes morphological and functional parameters of these organs prior to, during and after breeding season in live adult roe deer bucks. Size and morphology of the reproductive tract was monitored monthly by transcutaneous (testes, epididymis) and transrectal (accessory glands) ultrasonography. Semen was collected by electroejaculation. Concentration, motility and morphological integrity of spermatozoa as well as the content of proteins and testosterone in semen plasma were evaluated. Proportions of haploid, diploid and tetraploid cells were estimated by flow cytometry in testicular tissue biopsies. Serum testosterone was measured by enzyme immunoassay. Most parts of the male reproductive tract showed distinct circannual changes in size and texture. These changes were most pronounced in the testes, seminal vesicles, and prostate. All reproductive organs were highly developed during the rut only. The volume of ejaculates, total sperm number and percentages of motile and intact spermatozoa also showed a maximum during this period and corresponded with high proportions of haploid cells in the testis. The highest percentages of tetraploid cells were found in the prerutting period. The production of motile and intact spermatozoa correlated with both the protein content of semen plasma and the concentration of testosterone in semen plasma and blood serum. These results suggest the importance of combined actions of the testes and accessory sex glands and the crucial role of testosterone in facilitating the optimal timing of intensified semen production to ensure sufficient numbers of normal spermatozoa in seasonal breeders.     

Sexual selection affects the sizes of the mammalian prostate gland and seminal vesicles

The accessory reproductive glands of male mammals contribute the bulk of the secretions in which spermatozoa are transported to the female tract during copulation. Despite their morphological diversity,and the chemical complexity of their products,little is known about the possible effects of sexual selection upon these glands in mammals. Here we consider the seminal vesicles and prostate glands in a sample of 89 species and 60 genera representing 8 Orders of mammals. The sizes of the accessory glands are analysed in relation to body weight and testes weight. Both the seminal vesicles size and prostate size (corrected for body weight) correlate positively with relative testes size in this sample; this finding remains highly significant after application of procedures to correct for possible phylogenetic biases in the data set. The accessory reproductive glands are also significantly larger in those mammals which have large relative testes sizes,and in which the likelihood of sperm competition is greatest. These results support the hypothesis that sexual selection has played an important role in the evolution of the mammalian prostate gland and seminal vesicles.     

Relationship of food intake to the induction of plasma sex steroid-binding protein and testicular activity in immature male little brown bats (Myotis lucifugus lucifugus)

Immature male little brown bats were aroused prematurely from their first hibernation and fed ad libitum (Group AL) or given a restricted diet (Group FR). All animals were weighed daily and the food intake of Group FR males was restricted to maintain their body weights at or near initial post-arousal values (5.3-6.8 g). The average body weights of Group AL males increased during the first week after arousal and then stabilized at a level which was 20% higher than those of Group FR males. The post-arousal induction of plasma SBP was similar in Groups FR and AL: plasma SBP activity was significantly increased 1 week after arousal and by 3 weeks had reached levels which were more than 10-fold higher than those of immature hibernating males which served as controls. Although food restriction had no effect on plasma SBP levels, it did inhibit reproductive development. Arousal-induced increases in testicular and epididymal (head/body) weights in Group FR males were less than 50% of those in Group AL males. However, histological examination of the testes revealed similar degrees of spermatogenic activation in both groups. Plasma testosterone concentrations were increased markedly in Groups FR and AL; values were generally lower in Group FR but wide individual variations were observed. Despite these elevated peripheral testosterone values, the accessory sex glands in both groups remained unstimulated.     

Investigations on reproductive physiology in the male Eurasian lynx (Lynx lynx)

This study characterized (in vivo) morphological and functional parameters of reproductive organs of adult male lynx (n = 3) prior to, during, and after the breeding season (n = 3). Size and morphology of the reproductive tract were monitored by transcutaneous (testes) and transrectal (accessory sex glands) ultrasonography. Semen was collected by electroejaculation. Ejaculate volume, sperm number, motility, and morphology of spermatozoa as well as testosterone concentrations in blood serum and feces were evaluated. The testes and prostate had seasonal changes in size and echotexture. The mean (+/- S.D.) maximum and minimum testicular volume were 2.8 +/- 0.8 cm3 and 1.5 +/- 0.3 cm3, respectively. Fecal testosterone concentrations were highest in February (1240 +/- 393 ng/g feces), with a second increase in May (971 +/- 202 ng/g feces), but concentrations were lowest in January (481 +/- 52.9 ng/g feces). Ejaculate volume, total sperm number and percentage of motile, and intact spermatozoa were maximal in March (the middle of the breeding season). In one of the eight litters, multiple paternity was proven; however, in the remaining seven litters, all 16 cubs were sired by the same male. This particular male had the most developed and active testes and best semen quality, which may be important for sperm competition.     

Reproductive tract lesions in male mice treated neonatally with tamoxifen

Male mice of the NMRI/Tg strain were treated with tamoxifen for the first 3 days after birth. The affected mice were sterile, with multiple reproductive tract lesions. These lesions included testicular hypoplasia, intraabdominal testes, epididymal cysts, and squamous metaplasia of accessory glands.     

Anopheles culicifacies: effects of age on the male reproductive system and mating ability of virgin adult mosquitoes

Abstract. Under controlled laboratory conditions of 28–30^oC and 16:8 L:D photoperiod, an attempt was made to develop an age-grading technique for Anopheles culicifacies males. Mating activity was maximal when females were 5–12 days old and males were 5–7 days old. The numbers of total and mature spermatocysts declined significantly with age, and the proportion of the testes occupied by the sperm reservoir increased as virgin males grew older. Mating resulted in the loss of spermatozoa and accessory gland substance from the reproductive system. Loss of mating ability of older virgin males seemed to be age-related, because the reproductive system contained ample supplies of accessory gland substance and spermatozoa. Morphological changes of the reproductive system, due to mating and age, were used to infer the age and reproductive history of unknown males in a laboratory evaluation.     

Effect of depletion tests (DT) on the composition of boar semen

We conducted two depletion tests during the summer (DT 1) and winter (DT 2) to study their effect on selected biochemical parameters of boar semen. We subjected three boars to DT for 10 consecutive days. The first 3 days (Period 1) of ejaculate collections represented the reserves of the extragonadal spermatozoa and accessory sex gland secretions, whereas the other seven days (Period 2) represented the daily spermatozoa output and the secretory capacity of the accessory sex glands. We observed noticeable changes in the quantity and quality of the semen in DT 1 and 2. There was an increase in the number of spermatozoa with morphological defects, particularly coiled tails and detached acrosomes. The secretory activity of the accessory sex glands, particularly the vesicular glands, was slightly influenced by season. Depletion tests caused disturbances in the qualitative relations of secretions of the accessory sex glands, which were related to changes in the sperm plasmalemma integrity. These tests can be used to determine the total spermatozoa output, and to assess the secretory capacity of the accessory sex glands of boars.     

Annual variations in plasma sex steroid-binding protein and testosterone concentrations in the adult male little brown bat: relation to the asynchronous recrudescence of the testis and accessory reproductive organs

The annual reproductive cycle of the male little brown bat, in contrast to seasonal reproductive patterns of other mammals, is differentiated by an asynchronous recrudescence of the testis and the accessory reproductive glands. Spermatogenesis occurs during the summer, whereas fully stimulated accessory organs, stored epididymal spermatozoa, and sexual behavior are expressed later during a mating period that extends, albeit interrupted by hibernation, from late summer until early spring. To investigate whether changes in high affinity androgen-binding activity in the circulation are related to the delayed renewal of the accessory organs, plasma sex steroid-binding protein (SBP) and total testosterone (T) levels were measured throughout the year. From these data and determinations of association constants for T binding to SBP and albumin at both hibernating (4 degrees C) and active (40 degrees C) temperatures, estimates of the unbound ("free") and albumin-bound T fractions were made and correlated with changes in the accessory reproductive organs. Plasma SBP concentrations (mean +/- SEM) exhibited wide seasonal fluctuations: they were baseline in May (10 +/- 2 nM) following spring arousal, increased dramatically in June (184 +/- 24 nM), and reached peak levels in early July (262 +/- 29 nM), where they remained until August. In late August they began to fall (104 +/- 23 nM) and then returned to baseline during the hibernation period (October-April). Although total T levels were also elevated in June, it appeared that the unbound ("free") and the unbound plus albumin-bound T fractions did not increase until late July. Since the accessory gland weights did not begin to increase until late July as well, it was concluded that increases in the unbound and albumin-bound T fractions may be an important factor in the recrudescence of the accessories and that increased SBP activity in early summer may play a role in the regression and delayed renewal of these organs. However, what factor(s) maintain the accessory glands, epididymal spermatozoa, and sexual behavior during the breeding and hibernation periods when all T fractions were low are, as yet, undetermined.     

Anatomic,Histologic and Certain Enzymatic Studies on the Male Genital Organs of Hemiechinus auritus collaris Gray,the Indian Long Eared Hedgehog

Anatomically the male reproductive organs of Hemiechinus auritus collaris are of considerable interest and present a unique pattern of arrangement of different glands. The testes are inguinal and a true scrotum is absent. A pair of accessory glands, the seminal vesicles, are situated dorsal to the bladder. A pair of obviously lobulated glands, ventral to the bladder, represent the internal prostate and a pair of compact glands situated outside the pelvis in para-anal position the external prostate. The Cowper's gland and the gland of ampulla are absent. The present studies also concern enzymes of the phosphatase group, including both specific and non-specific phosphatases, in the testes and the sex accessory glands during both active and inactive periods in this insectivore.     

6种蝙蝠精子储存现象的组织学观察

精子储存是蝙蝠的生殖对策之一,有些种类的蝙蝠能将成熟精子在交配前(雄性)或交配后(雌性)储存在附睾或者输卵管及子宫内数月。采用冰冻切片和苏木精-伊红(H.E)染色法,观察了6种蝙蝠的睾丸、附睾、卵巢、输卵管和子宫,发现5种蝙蝠有精子储存现象。另外,本文还讨论了不同生殖对策蝙蝠的地理分布。     

Reproductive soundness of captive southern and northern white rhinoceroses (Ceratotherium simum simum, C.s. cottoni): evaluation of male genital tract morphology and semen quality before and after cryopreservation

White rhinoceroses suffer from a low rate of reproduction in captivity. This study examines the role of male reproductive function as a contributing factor. We used ultrasonography to image accessory sex glands, testis and epididymis. Electroejaculation provided 36 ejaculates from 21 rhinoceroses. Based on the percentage of progressively motile spermatozoa, semen was categorized in three groups, high (I: >75%), intermediate (II: 50-70%) or low (III: <50%) quality. Only 52% of the males showed high semen quality. Ejaculates in the high motility category also had the highest proportion of morphologically intact spermatozoa. Both semen parameters, sperm motility and morphology, were found to positively correlate with size of the accessory sex glands. The semen category was associated with group size suggesting that the social status influenced functional reproductive parameters. Change of territorial status (n = 1) improved semen quality. Testicular fibrosis was characterized as a sign of reproductive ageing in all males older than 15 years of age (n = 13); although, this ageing process did not notably affect semen parameters. Furthermore, for the benefit of assisted-reproduction and genetic banking programs protocols for the storage of cooled semen and the cryopreservation of spermatozoa were designed using different cryodiluents. This report provides basic data for the evaluation of reproductive components and of breeding management in male rhinoceros. Our results indicate that low rate of reproduction in captivity can be attributed to reduced male reproductive fitness. Changes in management of white rhinoceroses may positively affect male reproductive function.     

Reproductive biology of the male little mastiff bat, Mormopterus planiceps (Chiroptera:Molossidae), in southeast Australia

The anatomy, biology, and chronology of reproduction in the male of the long penile form of Mormopterus planiceps was studied in southeast South Australia and Victoria. In the morphology of its primary and accessory reproductive organs, M. planiceps was generally reminiscent of other Molossidae; however, in the specialized (sebaceous) nature of the Cowper's gland ducts, in the presence of para-anal glands, and in the unusual, horizontally bifid glans penis and the greatly elongated os penis, it was distinct from other Molossidae studied to date. Young of the year were not reproductively active. Adults displayed a single annual spermatogenic cycle that commenced in spring (September/October) and culminated in spermiogenesis in autumn (February-May), during which period plasma levels of testosterone overtook androstenedione. Thereafter, spermatogenesis appeared to cease (though scattered sperm were seen in the seminiferous tubules until August), but abundant epididymal sperm reserves persisted until September/(October). The accessory glands were hypertrophied during this period, becoming involuted by October. Although the numbers of animals available for study were small, these observations, together with the appearance of spermatozoa in the ductus deferens in August/September suggested that mating could occur during the interval from autumn to spring. Late winter/spring insemination is normal for molossids from temperate environments. However, protracted spermatogenesis commencing in spring that is not accompanied by the availability of spermatozoa until autumn, and a subsequent apparent extension of fertility (epididymal sperm storage, accessory gland hypertrophy) beyond the testicular gametogenic phase, are aspects of the male reproductive cycle in M. planiceps that have not heretofore been described in another molossid bat.     

Seasonal changes in plasma testosterone concentrations and Leydig cell and accessory gland activity in the Cape horseshoe bat (Rhinolophus capensis)

Male Cape horseshoe bats were studied in the Cape Province of South Africa (33 degrees 17'S, 26 degrees 25'E) between January 1983 and June 1985. The reproductive cycle is characterized by reactivation of the seminiferous tubules in early summer (October) after a 4-month (June to September) period of winter inactivity. Spermiogenesis occurred between January and April, and spermatozoa were released to the epididymides in April and May. Spermiogenesis was associated with Leydig cell activity and increasing plasma testosterone concentrations. At this time components of the reproductive accessory glands became secretorily active or showed increasing secretory activity. During winter Leydig cells were secretorily inactive and plasma testosterone concentrations dropped, but components of the accessory complex remained active. There was a second period of Leydig cell secretory activity and increasing and peak plasma testosterone values in late winter/early summer which may be associated with copulation or the initiation of a new cycle of spermatogenesis.     

Characterization of the semen quality of postpuberal boars with spontaneous unilateral abdominal cryptorchidism on the right side.

In recent studies, we found that the ectopic testis from postpuberal boars with unilateral abdominal cryptorchidism does not produce sperm. Therefore, in these males, the seminal characteristics can be used as indicators of the activity of the scrotal testis and its epididymis and also the accessory glands. The semen quality (ejaculate volume, cell-rich fraction volume, sperm concentration, sperm vitality, sperm motility, sperm morphology and cephalic stability of spermatozoa) was evaluated in healthy postpuberal boars and in postpuberal boars with unilateral abdominal cryptorchidism on the right side. In comparison with the healthy boars, the unilateral abdominal cryptorchid boars showed a significant decrease of the ejaculate volume, sperm concentration and sperm motility. The low sperm concentration indicated that unilateral abdominal cryptorchidism severely impairs the sperm production of the scrotal testis. The decrease of ejaculate volume was attributed to an abnormal activity of the accessory glands. The alterations in sperm motility develop as a result of dysfunctions in the epididymal epithelium and/or the accessory glands. The sperm vitality, sperm morphology and cephalic stability of spermatozoa maintained normal values; therefore, at testicular level, despite the low sperm production, the germ cell differentiation is not disturbed. At epididymal level, the morphological maturation of spermatozoa is not altered.     

Possible role of changes in post-natal gonadotrophin concentrations on permanent impairment of the reproductive system in neonatally oestrogenized male rats

Rats were treated neonatally with oestrogen (500 micrograms oestradiol benzoate injected on Day 1 of life). Treatment with FSH and LH (80 micrograms/100 g body wt and 40 micrograms/100 g body wt respectively) during the early post-natal period (Days 1-10) abolished the effects of oestradiol on the morphological and functional development of the testes and on the regulation of prolactin secretion, but had no action on the effects of oestradiol on the development of the sex accessory glands. Treatment with prolactin (100 micrograms/100 g body wt) during the early post-natal period did not affect the integrity of the reproductive system in adult life. These results suggest that neonatal oestradiol acts indirectly, through an inhibition of gonadotrophin secretion on testicular development, and directly on the development of the sex accessory glands.     

Components of stallion seminal plasma and the effects of seminal plasma on sperm longevity

Seminal plasma is a mixture of secretions produced in the testes, epididymides and accessory sex glands, and ejaculated as several consecutive fluid fractions. The composition of seminal plasma and the effects on sperm longevity vary between fractions and individual stallions. This review focuses on the sequence of ejaculation, constituents of seminal plasma and their potential use as fertility markers as well as the influence of seminal plasma on spermatozoa during storage.     

Ultrastructure and function of the seminal vesicle of Bittacidae (Insecta: Mecoptera)

The fine structure of the seminal vesicle and reproductive accessory glands was investigated in Bittacidae of Mecoptera using light and transmission electron microscopy. The male reproductive system of Bittacidae mainly consists of a pair of testes, a pair of vasa deferentia, and an ejaculatory sac. The vas deferens is greatly expanded for its middle and medio-posterior parts to form a well-developed seminal vesicle. The seminal vesicle is composed of layers of developed muscles and a mono-layered epithelium surrounding the small central lumen. The epithelium is rich in rough endoplasmic reticulum and mitochondria, and secretes vesicles and granules into the central lumen by merocrine mechanisms. A pair of elongate mesodermal accessory glands opens into the lateral side of the seminal vesicles. The accessory glands are similar to the seminal vesicle in structure, also consisting of layers of muscle fibres and a mono-layered elongated epithelium, the cells of which contain numerous cisterns of rough endoplasmic reticulum and mitochondria, and a few Golgi complexes. The epithelial cells of accessory glands extrude secretions via apocrine and merocrine processes. The seminal vesicles mainly serve the function of secretion rather than temporarily storing spermatozoa. The sperm instead are temporarily stored in the epididymis, the greatly coiled distal portion of the vas deferens.