Formation Of Spermatids Research Articles

Effect of safe concentrations of some pesticides on testicular recrudescence in the freshwater murrel, Channa punctatus (Bl.): A morphological study

The effects of safe concentrations of fenitrothion 50% E.C., an organophosphate, and carbofuran 3% G, a carbamate, on testicular recrudescence of Channa punctatus during the maturing, prespawning, and spawning phases (15th April through 12th August, 1980) of the annual reproductive cycle have been studied. The results reveal that compared to the carbofuran treatment, the fenitrothion treatment was more effective in lowering testicular weights. Furthermore, the carbofuran treatment delayed the formation of spermatids and sperm, since their occurrence in the testes was observed at 90 days of exposure, but at 60 days of exposure in the control fish. The fenitrothion treatment not only delayed the formation of spermatids, but also arrested the formation of sperm, since most of the spermatids had undergone necrosis. The exposure for 120 days to safe concentrations of carbofuran/fenitrothion also resulted in the necrosis of spermatogonia and spermatocytes, which led to their gradual loss. As such, the lobules completely devoid of the spermatogenetic stages were observed in the testes of the treated fish. The occurrence of such empty lobules, however, was relatively greater in the fenitrothion-treated fish. The formation of the collagenous capsules around the necrotic germ cells was also observed in the treated fish testes. The interstitial (Leydig) cells were in the involuted condition in the treated fish testes, but active in the control fish.

The role of the mammalian Y chromosome in spermatogenesis.

All aspects of the mammalian male phenotype are due either directly or indirectly to Y-chromosome activity. This review summarizes what is known of the role of the Y in male germ cell differentiation in the mouse. The initial diversion of germ cells to the male pathway in fetal life (that is the formation of amitotic T1-prospermatogonia rather than meiotic oocytes) is an indirect effect of the Y: the Y-chromosomal testis-determining gene (Tdy) acts to create a testis and the testicular environment causes the germ cells to follow the male pathway. XX and XO germ cells can therefore form T1-prospermatogonia, but the extra X of XX prospermatogonia in some way causes their death perinatally. The first direct effect of the Y in the germ line occurs at the initiation of the spermatogenic cycles (approx. 1 week after birth) when a Y-chromosomal gene (Spy) is needed for normal spermatogonial survival and progression to meiosis. Spy is present in the Y-derived Sxr fragment so XOSxr germ cells enter meiosis normally. An Sxr derivative, Sxr', which has lost the capacity to produce H-Y antigen, has also lost the Spy function, raising the possibility that H-Y antigen is the mediator of Spy activity. The Y is next required in the male germ line during meiotic prophase, when it provides a pairing partner for the X chromosome. If the X (or, indeed, the Y when present) remains unpaired, there are severe spermatogenic losses and the second meiotic division is frequently omitted, leading to the formation of diploid spermatids.(ABSTRACT TRUNCATED AT 250 WORDS)

Frequency Distribution of Cell Numbers in the Spermatocysts during the Annual Testicular Cycle in the Indian Frog Rana tigerina

Annual changes in (1) the frequency distributions of cell numbers in the sectioned cysts of the three consecutive stages of spermatogenesis, the secondary spermatogonia, primary and secondary spermatocytes, (2) the mean numbers of spermatocysts of different stages of spermatogenesis per tubule cross section, and (3) the Leydig cell nuclear diameters were studied in the frog Rana tigerina. The mitotic proliferation of secondary spermatogonia was very slow during July-February and mitotic rate increased between March-June. The meiotic divisions, the formation of secondary spermatocytes and spermatids as well as spermiogenesis were mainly confined to May-June. The total number of spermatocysts per tubule cross section were highest during May-June. Leydig cells showed clear cut seasonal variation in their cytomorphology, being active between May-June and regressed during other months. Thus, there is a good correlation between the Leydig cell activity and proliferation and differentiation of germ cells in the testis of R. tigerina unlike that found in temperate frogs.

Spermatogenesis in vitro: completion of meiosis and early spermiogenesis.

In vitro formation of haploid spermatids has not been convincingly demonstrated in mammals. To investigate this problem we selected defined segments of rat seminiferous tubules containing late pachytene and diakinetic primary spermatocytes (Stages XII and XIII of the cycle) for culture in a chemically defined medium. After 2 days, most spermatocytes completed both meiotic divisions, and by 6 days the tubular epithelium developed morphologic characteristics of Stage V in which the newly formed spermatids had acrosomic systems characteristic of step 5 spermiogenesis. The seminiferous tubules also differentiated biochemically as evidenced by increased production of proteins characteristically secreted by Stage V. Since this in vitro differentiation of the germinal epithelium occurred in the absence of testosterone and FSH, we conclude that late pachytene spermatocytes and their associated Sertoli cells have all the information required for both meiotic divisions and early spermiogenesis.

Cytogenetic and histological studies of testicular biopsies from subfertile men with chromosome anomaly.

Testicular biopsies from eight men with abnormal karyotypes have been examined for histological and cytogenetic evidence of disturbances of meiosis. Quantitative analysis of this material showed one, with a 13;14 Robertsonian translocation, to have apparently normal spermatogenesis. Three patients, one with a 47,XYY and two with 45,XY, inv 9 karyotypes, had an overall depression of spermatogenesis. Four others, all with major chromosomal abnormalities, had apparently normal spermatogenesis until the primary spermatocyte stage. Two of these had sex autosomal translocations. One, 45,Y,t(X;21), had a complete block at MI, the other, 46,X,t(Y;16), had a partial block at spermatid formation. One man with a reciprocal 2;10 translocation showed delay at all stages beyond spermatocyte formation and one man with an inversion of chromosome 3 showed impaired spermatid maturation.

In vitro spermatogenesis in Drosophila. I. Development of isolated spermatocyte cysts from wild-type D. hydei.

In vitro spermatogenesis of isolated single spermatocyte cysts of Drosophila hydei was studied by microscopic observations and time-lapse cinematography. Cysts of spermatocytes isolated during diplotene develop as far as the coiling stage of spermatid differentiation. The existence of an interphase between meiosis I and meiosis II is, for the first time, documented. Meiosis, Nebenkern formation, and elongation of spermatids occur just as in D. melanogaster; however, an individualization cone, as described for D. melanogaster, can not be detected.

Role of FSH in the control of testicular function.

Follicle stimulating hormone (FSH) binds to the plasma membranes of Sertoli cells and, apparently, spermatogonia; the hormone may then be taken into the cytoplasm of its target cells and metabolized there. In the immature testis, binding of FSH to Sertoli cells leads to activation of adenylate cyclase, formation of cyclic AMP (cAMP), and activation of a cAMP-dependent protein kinase. There is a subsequent increase in the rates of RNA, protein, and DNA synthesis. Normal adult testis is unresponsive to FSH, one reason being the destruction of cAMP by a phosphodiesterase. After hypophysectomy of adult animals this enzyme disappears and FSH is again able to stimulate RNA and protein synthesis. Other factors contributing to the insen-sitivity of the mature testis are an FSH binding inhibitor, a protein kinase inhibitor, and in-activation of FSH.FSH increases the formation by Sertoli cells of structural proteins and an androgen-binding protein (ABP) that the Sertoli cells secrete into the extracellular fluid surrounding the cells of the germinal epithelium. It is thought that ABP buffers fluctuations in the concentration of androgen in the extracellular fluid of the germinal epithelium as well as transporting androgen to the lumen of the epididymis.In immature animals FSH increases the number of Sertoli cells, which accounts for the testicular hypertrophy that follows hemicastration. FSH is responsible for maturational changes in immature Sertoli cells and for morphological changes associated with in vitro aggregation of Sertoli cells to form colonies. FSH-induced changes in the shape of Sertoli cells are mediated by a calcium-dependent regulator protein, calmodulin. FSH also stimulates the Sertoli cells to secrete a plasminogen activator whose role is not known.FSH has effects on testicular germ cells in immature animals and during the restoration of spermatogenesis in adults, but it is not known whether the Sertoli cells mediate its actions on the germ cells, though this would seem likely. Administration of FSH to immature rats and mice increases the number of spermatogonia by reducing the proportion that degenerate. This may be due to a stimulatory effect of the hormone on DNA synthesis. Androgen and FSH appear to act synergistically to stimulate accumulation of primary spermatocytes and formation of spermatids in immature rats. During the restoration of spermatogenesis in adult rats and mice FSH also acts synergistically with androgen, increasing the proportions of cells passing through meiosis and spermiogenesis. Immunization experiments suggest that FSH is needed for the formation of normal numbers of spermatocytes and spermatids in immature animals, but studies in adults have given conflicting results.FSH appears to influence development of the interstitial tissue, particularly by inducing luteinizing hormone (LH) receptors on Leydig cells. The presence of some LH may be necessary for FSH to have this effect. FSH can stimulate a number of steroid transformations, such as conversion of testosterone to dihydrotestosterone (DHT), in Sertoli cells from immature rats but there is no conclusive evidence that the gonadotropin is capable of stimulating the critical step in steroidogenesis, production of pregnenolone from cholesterol. FSH also stimulates Sertoli cells from immature rats to convert testosterone to a substance cross-reacting with antibodies to estradiol. It has been suggested that loss of the ability of FSH to stimulate estrogen production in maturing Sertoli cells allows the Leydig cells to secrete increased amounts of androgen at puberty.Highly purified preparations of human gonadotropins are not available in sufficient quantity for clinical use. Menopausal gonadotropin, which contains LH as well as FSH activity, stimulates proliferation of immature Sertoli cells and spermatogonia and formation of spermatocytes in prepubertal boys. Treatment with human chorionic gonadotropin (hCG) has similar effects but in addition early spermatids are formed when both preparations are given together. Stimulation of spermatogenesis and, rarely, fertility have occurred in a proportion of eunuchoidal men treated with gonadotropin preparations containing both FSH and LH activity, and combined treatment has also stimulated spermatogenesis after hypophysectomy. Unfortunately gonadotropin treatment has benefited only a small proportion of azoospermic or oligozoospermic men not suffering from androgen deficiency. Isolated deficiency of FSH has been reported in four men but these reports throw little light on the role of FSH in the control of testicular function in normal men.Most studies in immature animals leave little doubt that FSH has an essential role in the stimulation of developmental changes in the testis. At this stage androgen secreted in response to LH may act synergistically with FSH on the germinal tissue. In the normal mature testis it is not clear whether there is a requirement for FSH. If so, its place is subordinate to that of androgen.

Histophysiological effects of an antiandrogen (cyproterone acetate) on the testis of the frog Rana temporaria.

An attempt was made to study the effects of cyproterone acetate (CA), an antiandrogen, on the testicular activity of the frog Rana temporaria, employing histological and histochemical methods. Each treated frog received a total dose of 4 mg during the period of 4 weeks. Light-microscopic examinations revealed that CA blocked the formation of spermatids and mature sperms; however, the early stages of spermatogenesis, i.e. proliferation and development of spermatogonia and spermatocytes, remained unaffected. CA caused interstitial tissue disruption and degeneration, and led to the shrinkage of Leydig cells; the drug stopped the production of lipoidal material in the interstitial tissues. Also, a loss of testicular weight was documented in the frogs treated with CA.

Seasonal histological changes in the gonads, thyroid and adrenal of the Canada goose (Branta canadensis interior).

Cyclic histological changes in the testis, ovary, thyroid and adrenal of the North American eastern prairie population of Canada geese (<i>Branta canadensis interior</i>) breeding in Ft. Churchill (Manitoba, Canada) and wintering in the Swan Lake refuge in Missouri (USA) were studied. The investigation was carried out during the following six periods of the yearly life cycle. Phase 1: pre-spring migration at Swan Lake (early March); phase 2: post-spring migration at Ft. Churchill (early May); phase 3: breeding (early June); phase 4: moult (early August); phase 5: pre-fall migration (early September); phase 6: post-fall migration at Swan Lake (mid-October). The development of the testis and the initiation of spermatogenesis up to the formation of secondary spermatocytes was begun in phase 1. All stages of spermatogenesis, including the formation of spermatids and spermatozoa, were reached by the end of phase 2 and remained so through most part of phase 3. The weight of testis recorded was highest in phases 2 and 3. Testicular regression characterized by progressive loss in weight, reduction of spermatogonia in the tubules and appearance of sudanophilic material in the intersititium commenced in phase 4 and lasted through phases 5 and 6. Though the initiation of ovarian development probably started in phase 1, the ovary weighed the highest in phase 2. At this time, the ovary contained numerous maturing ova in different stages of development and lipoidal atresia. Lipoidal atresia was more prominent among young small ova. The larger maturing ova were characterized by a more distinct granulosa layer around the oocyte. Numerous sudanophilic interstitial cells were present scattered throughout the ovarian stroma. Atretic follicles and scars from discharged follicles were found in all the phases. The thyroid showed a significant increase in weight during moult (phase 4). No marked histological changes were discernible in all the phases. The increase in weight during moult is

Gamma-glutamyl transpeptidase activity in the developing rat testis. Enzyme localization in isolated cell types.

The purpose of this study was to correlate gamma glutamyl transpeptidase (γ-GTP) activity with the morphological changes occurring in the rat testis during sexual maturation and to determine the cell type(s) responsible for the activity of this enzyme. The γ-GTP activity was measured at different ages in whole testis homogenates, isolated specific cell types and cultured Sertoli cells. The specific activity of γ-GTP, expressed as units per mg of protein (U/mg P), in whole testis homogenates increased with age of animals, reaching maximum value (0.60 ± 0.03 U/mg P) by the 20th day, thus, prior to the formation of spermatids, and then remained essentially unchanged until Day 100. When individual cell types were isolated from 30-day-old rat testis, the specific activities of γ-GTP in the Sertoli cells and the germ cells respectively were 0.93 ± 0.07 U/mg P and 0.12 ± 0.05 U/mg P. The peritubular cells and interstitial cells contained non-detectable γ-GTP activity. These results indicate that in 30-day-old rat testis the γ-GTP activity is associated mainly with the Sertoli cells. The γ-GTP activity of the isolated Sertoli cells was also investigated after various culture periods at 34°C. The specific activity of γ-GTP in the cultured Sertoli cells increased with culture age, showing a 5-fold increase after three days of incubation and a 20-fold increase after seven days of culture. The physiological significance of γ-GTP activity in the Sertoli cells and its increase under culture conditions remain unclear, but the enzyme may play a role in the synthesis of specific proteins known to be secreted by the Sertoli cells.

Effects of photoperiod and temperature on plasma gonadotropin and spermatogenesis in the rainbow trout Salmo gairdnerii Richardson

Two-year old male rainbow trout, Salmo gairdnerii, were exposed to the following photoperiods at 80 or 16 °C from February 24 to June 19 : constant short photoperiod (8 L +16 D), constant long photoperiod (16 L + 8 D), and gradually decreasing photoperiod (from 16 L to 8 L). Control fish were exposed to natural photoperiod and temperature. Plasma and pituitary gonadotropin levels were determined by radioimmunoassay and correlated with spermatogenic response in testes. Control fish did not show advancement of spermatogenesis, whereas those exposed to decreasing photoperiod at 80 or 16 °C showed complete induction of spermatogenesis. While cooler temperature favoured production of spermatogonia and spermatocytes, the warmer temperature stimulated formation of spermatids and spermatozoa. On the other hand, in trout exposed to constant short or constant long photoperiod, spermatogenic response was weak at both temperatures. Plasma GtH levels increased in groups kept under decreasing photoperiod at both 8 °C as well as 16 °C ; the magnitude of rise of GtH was greater at 16 °C than at 8 °C. GtH levels were significantly higher in trout exposed to gradually decreasing photoperiod than in animals kept under constant short or constant long photoperiod at 80 or 16 °C. The data suggest that the optimum photothermal combination for GtH release and induction of spermatogenesis in the rainbow trout is a gradually decreasing photoperiod (from 16 L to 8 L) at 16 °C.

The control of spermatogenesis in the green frog, Rana esculenta

AbstractThe process of spermatogenesis in Rana esculenta (living in the surroundings of Naples) resurges gradually in the spring months, proceeds actively through the summer and declines gradually in the winter months reaching an almost total “quiescence” for a short length of time. The repeating from year to year with a distinct regularity of spermatogenetic cycle suggests that environmental cues play a role in timing its various phases. Both temperature and photoperiod appear to be potential modifiers of spermatogenetic activity in this species. It is, however, probable that photoperiod acts only in a permissive way to facilitate the temperature response which seems to be the more direct modifier of the testicular activity.The proliferation of primary spermatogonia seems to be favoured by only low temperatures. The formation of secondary spermatogonia, and primary and secondary spermatocytes occurs when there occurs a gradual increase in the ambient temperature, day length and gonadotropin secretion. This period is characterized by very low plasma level of testosterone, that, through the reduced negative feedback to the hypothalamus, favours an increased secretion of FSH‐like gonadotropin. Spermatid formation is entirely androgen‐dependent as confirmed by the use of a specific antiandrogen, cyproterone acetate. In fact spermatid formation naturally occurs in a period when plasma level of testosterone is increasing and pituitary gonadotrops are declining in their secretory activity. In this period the ambient temperature and the photoperiod gradually decline.The importance of lateral eyes and the pineal gland in the mediation of influence of photic cues has been shown. It seems that without either the eyes or the pineal gland both light and temperature are completely ineffective in stimulating the early spermatogenesis, which shows the permissive role of light on temperature influence upon spermatogenesis.Hypophysectomy impairs spermatogenesis, which can be restored by a replacement therapy with homoplastic pituitary extract. Testosterone alone does not restore spermatogenesis except enhancing spermatid formation. Pituitary extract stimulates mitotic activity of spermatogonia and formation of primary and secondary spermatocytes. Testosterone is not involved because the stimulatory effects of pituitary extract are only marginally blocked by the antiandrogen. In fact spermatogonial multiplication is partially inhibited, while spermatid formation is totally blocked, indicating that ICSH‐like gonadotropin acts upon the formation of spermatids through the stimulation of testosterone production.Thus it has been found that there exists a complex interaction between the environmental factors and the “endogenous hormonal trigger” that subsequently steps into the regulation of spermatogenesis.

Changes in 5α- dihydrotestosterone binding to epididymal cytosol during sexual maturation in rabbits: Correlation with morphological changes in the testis and epididymis

We previously demonstrated that the caput epididymis of intact sexually mature rabbits contains a specific high-affinity binding protein for 5α-dihydrotestosterone (5αDHT). The other anatomical segments (corpus and cauda) of the epididymes of these animals had no detectable 5αDHT-binding activity. We have further shown that this binding was due to an androgen-binding protein of testicular origin. In the present study we have investigated 5αDHT binding to epididymal cytosol from sexually immature rabbits (20−104 days old). Using sucrose gradient ultracentrifugation, we have detected a unique pattern of binding. The pattern correlated well with testicular and epididymal maturation, but there was little correlation with chronological age or body weight. In the most immature animals (Group I) the seminiferous tubules appsared as solid cords and the epithelium of the ductus epididymis consisted of a single row of columnar cells. Epididymes from this group had little or no detectable 5αDHT-binding activity. In the second group (Group II), there was 5αDHTbinding to all three segments. The seminiferous tubules of these rabbits exhibited spermatogenic activity and lumen formation. The height of the epididymal epithelium had increased uniformly throughout the duct. The third group (Group III) had 5αDHT-binding only in caput cytosol. Spermatogenesis had progressed to the formation of elongated spermatids in the most immature animals of this group to the release of spermatozoa in the most mature ones. The caput epithelium of this last group of rabbits was fully differentiated. Unilateral orchidectomy of Group II rabbits resulted in a decrease in [ 3H]5αDHT-binding activity on the operated side as compared to the contralateral non-operated control side, suggesting the testicular origin of the binding protein. The failure of cyproterone or cyproterone acetate to inhibit [ 3H5αDHT-binding to the protein, the lack of effect of N-ethylmaleimide on binding, and the rapid dissociation rate of the[ 3H5αDHT-binding protein complex suggested that the binding moiety was testicular androgen-binding protein (ABP).

Effect of 5alpha reduced androgens on sex accessory organs, initiation and maintenance of spermatogenesis in the rat.

The effect of several androgens on initiation and maintenance of spermatogeneSis was studied in newborn estrogen-blocked and in adult hypophysectomized rats. The steroid treatment inhibited testicular and body weight in all animals. Treatment of estrogen-blocked animals with androgens resulted in a stimulation of the growth of sex accessory organs, except in the case of androsterone. Initiation of spermatogenesis and its progression to mid pachytene stage (first wave) was observed in all steroid treated rats. In estrogen-blocked animals the first wave of spermatogenesis proceeded only to pachytene spermatocytes. Administration of testosterone propionate. dihydrotestosterone or 5a-androstanediol to these animals resulted in completion of meiosis and formation of spermatids up to Step 8 of spermiogenesis. Completion of meiosis was not observed in androsterone treated rats. In hypophysectomized animals all 5a-reduced androgens maintained spermatogenesis similar to testosterone.

Hormonal regulation of isoenzymes of N-acetyl-beta-glucosaminidase and beta-galactosidase during spermatogenesis in the rat.

Isoenzymes of beta-galactosidase and of N-acetyl-beta-glucosaminidase were assayed during development of rat testis and as a function of hormonal treatments. Isoenzyme 1 of beta-galactosidase was highest in specific activity in the 4-day-old testis, at a point when Sertoli cells and gonocytes were the predominant cell type. Beta-galactosidase II, previously shown to be associated with the sperm acrosome, was undetectable through the spermatocyte stage of development, but increased in specific activity during the formation of spermatids. The specific activities of isoenzymes I and II of N-acetyl-beta-glucosaminidase increased markedly in association with the formation of spermatogonia and spermatocytes, and then declined with the appearance of spermatids. Following hypophysectomy of rats at 26 days of age or in adulthood the specific activities of the lysosomal enzymes beta-galactosidase I and N-acetyl-beta-glucosaminidase I and II increased markedly, while the acrosomal beta-galactosidase II was undetectable. The normal patterns of isoenzyme distributed were restored completely by administration of LH and FSH or testosterone to hypophysectomized animals. These results thus demonstrate specific patterns of isoenzyme concentration during spermatogenesis. Formation of the acrosome in developing spermatids is associated with the induction of new forms of beta-galactosidase (isoenzyme II) and N-acetyl-beta-glucosaminidase (sperm isoenzyme). These molecules appear to be specialized forms which may participate in fertilization, and their induction is dependent upon the actions of gonadotropins or testosterone.

Cyclic variations in Sertoli cell lipid content throughout the spermatogenic cycle in the rat.

The formation, distribution and fate of lipid inclusions within the seminiferous tubules of the rat has been studied throughout the spermatogenic cycle. The occurrence of lipid inclusions within the Sertoli cell exhibited cyclic variations with the stages of the rat seminiferous cycle. At stage 9 of the cycle, residual bodies of maturing spermatids were phagocytosed by the Sertoli cell and released numerous lipid droplets which appeared to coalesce into large inclusionsat the base of the Sertoli cell at stage 10. The Sertoli cell lipid inclusions persisted througout the completion of meiosis (stages 11 to 14) and the formation of young spermatids (stages 1 to 2) and their numbers appeared to reach a peak at stages 12 to 13 of the cycle. The inclusions decreased markedly within the Sertoli cell cytoplasm during stage 2 and remained low untilstage 9 when lipid from the residual bodies again became available to the cell. This cyclic variation of lipid inclusions within the Sertoli cell does not support previously held views that there is a gradual decline in Sertoli cell lipid during stages 10 to 14 of the spermatogenic cycle. A hitherto unnoticed finding was the presence of large lipid inclusions in the cytoplasm of late pachytene to diakinetic spermatocytes, and some observations suggest a transfer of these lipid inclusionsfrom the Sertoli cells to primary spermatocytes.

Lipid and fatty acid composition of testes of quaking mice.

Testes of quaking mice (sterile mutants) and of controls were analyzed for major lipid classes and fatty acid composition. Of the main lipid classes, only cholesterol esters differed significantly in concentration between the two groups (1.01 for quakers vs 0.69 mg/g wet wt of tissue for controls). The concentration of triglycerides was 4.5-5.0 that of total phosphatides 18-19 and that of free cholesterol 1.9-2.0 mg/g for mutants and controls. The concentrations of phosphatidyl ethanolmanine and of sphingomyelin were both lower in quaking than in normal mice, but only the change in the former was statistically significant. Phosphatidyl choline was the major phosphatide (43-45% of total phosphatides) followed by phosphatidyl ethanolamine (24-26%) and sphingomyelin, phosphatidyl serine, and phosphatidyl inositol (all ca. 7% of total phosphatides). Minor differences between the mutants and controls were observed in concentrations of fatty acids of major lipid classes. The mutants, sterile because of faulty spermatid differentiation, had normal quantities of 22:6 w3 and 22:5 w6. These data are consistent with the hypothesis that the 22-carbon polyenes are associated with the formation of spermatids, rather than with their final differentiation into spermatozoa.

Hormonal Regulation of Uridine Diphosphatase during Spermatogenesis in the Rat1

Uridine diphosphatase, a protein marker of internal cytoplasmic membranes, and 5'–nucleotidase, a protein marker of plasma membranes, have been studied in terms of their SA and cytochemical localization during spermatogenesis in the rat. The plasma membranes of all the germinal epithelial cells stained for 5'–nucleotidase activity. The SA of this enzyme increased markedly during the formation of spermatogonia, and was unaltered by hypophysectomy or injections of testosterone or pituitary gonadotropins. The SA of UDPase increased markedly with the formation of spermatogonia and spermatocytes (up to 26 days of age), and then decreased sharply with the formation of spermatids, in which cells the enzyme was not detectable by cytochemical staining techniques. Hypophysectomy of the adult rat (58–60 days) induced a loss of spermatids and a rapid increase of the specific activity of UDPase to levels characteristic of the 26–day—old rat. Treatment of hypophysectomized rats with LH and FSH or with testosterone induced the normal pattern of decrease in UDPase concentration with spermatid maturation. UDPase serves as a marker protein for internal cytoplasmic membrane formation in spermatogonia and spermatocytes, and its absence from developing spermatids represents a specific hormone—dependent biochemical transition during spermatogenesis. (Endocrinology91:415, 1972)

Cytological Investigations On the Male Reproductive System and the Sperm Track in the Spider Mite Tetranychus Urticae Koch (Tetranychidae, Acarina)

The post-embryonic development of the male internal genitalia, the development and production of the male germ cells, and the sperm track in the female of the two-spotted spider mite Tetranychus urticae Koch has been described. The male reproductive system consists of a testis, two vesiculae seminalis, a sperm pump, a ductus ejaculatorius and an aedeagus. The testis is a single structure in the larva, but during the nymphal stages it is generally divided into a right and a left half. The vesiculae seminalis develop from groups of cells which lie, in the larva, against the lateral sides of an epidermal invagination underneath the testis. In adults the vesiculae are provided with vesicular compartments which originate from the sheath cells. The sperm pump differentiates from the distal part of the invagination and some cells surrounding the latter. The remainder of the invagination forms the ductus ejaculatorius and aedeagus. The germ cells multiply by asynchronous spermatogonial mitoses. They are haploid with three chromosomes. Spermatocytes were not observed, which means a complete reduction of the meiosis. Spermatid formation begins at the nymphochrysalis stage and spermatozoa are found already at the deutochrysalis stage. During spermiogenesis the chromosomes lie in a line suggesting a non-random distribution in the sperm nucleus. The ripe spermatozoon is a spherical nucleus surrounded by two layers of plasm. A nuclear membrane and mitochondria were not observed. Germ cell production is continuous during the lifetime of the male, whether the males copulate or not. The numbers of the various germ cells vary dependent on the stage of life. The numbers of spermatozoa in the vesiculae seminalis and the sperm pump vary considerably, even if copulation does not take place. The numbers do not decrease during the first eight days of adulthood. The males produce an excess of spermatozoa. Ejaculations without copulation may take place. During copulation the spermatozoa are transferred behind each other with the aid of the sperm pump and may then become long-drawn because of a narrow ductus ejaculatorius or a narrow penial canal. One normal insemination supplies the female with a sufficient number of spermatozoa. The entrance to the receptaculum seminis is a short narrow tube which runs from an opening in the epidermis behind the genital opening. The receptaculum is situated posterior to the exit ducts of the ovarium and consists of about forty cells surrounding a lumen. Immediately after copulation spermatozoa are in the lumen and the basal parts of the cells. They may thus be transformed, though recovery takes place, and may adhere together forming packets. They migrate through the cells towards the haemolymph, which may take place within one day. Under influence of the growth of the oocytes and the movements of the mature eggs single spermatozoa are transported in the haemolymph towards the oocytes.

Effects of gonadotropins and testosterone on the testes of prepubertal mice.

AbstractPituitary follicle‐stimulating hormone FSH supports the synthesis of testicular proteins prior to the onset of spermatid formation. Supplementary FSH enhances the activities of certain enzymes that generate reduced nicotinamide adenine dinucleotide phosphate (NADPH) and induces the division and differentiation of Leydig cell precursors. In addition, exogenous FSH counteracts the effects of continued treatment with testosterone on Leydig cells up to the third week postpartum and offsets the effects of the steroid on the weights of the prepubertal testis and seminal vesicles. In its antagonism of testosterone and its activation of glucose‐6‐phosphate dehydrogenase (G6PDH), FSH clearly differs from the interstitial‐cell‐stimulating hormone ICSH during the first wave of spermatogenesis in the mouse testis.