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Differential distribution of laminin chains in the development and sex differentiation of mouse internal genitalia.

The distribution of laminin chains and basement membranes (BMs) in the ontogenesis and sex differentiation of male and female mouse gonads and mesonephros was studied by conventional and immunocytochemical light and electron microscopy. The alpha 1 (synonymous to A) chain was recognized with MAbs against fragment E3, and three chains of laminin with PAbs raised against EHS-laminin. BMs, which formed around the mesonephric duct, the mesonephric tubules, and the paramesonephric duct, contained the laminin alpha 1 chain. The alpha 1 chain appeared with epithelial differentiation in the developing gonads in both sexes. The alpha 1 chain was first evident around the embryonic gonadal cords and remained, after development, in the BMs of the testicular cords and ovarian follicles. The laminin alpha 1 chain was also detected in BMs of the myoid cells around the epithelial rete cords, and transiently in the surface epithelium and in the corpus luteum. Laminin beta-gamma chains were found in many locations where the alpha 1 chain was not detected. These included the mesenchyme of the early mesonephros, the BMs of blood vessels and surface epithelium in the differentiated testis and ovary, between the theca cells in the ovary, and in some corpora lutea. The morphological differentiation of the BMs of the embryonic testicular cords proceeded rapidly. In contrast, the BM of the ovarian cords remained relatively poorly differentiated during the prenatal phases, and developed concomitantly with the differentiation of the follicles. The results show that BMs in the differentiating internal genitalia are heterogeneous with respect to their laminin chains, and suggest that all known laminin chains must be analyzed in the differentiation of gonadal epithelia for a complete role of the BMs in gonadal sex differentiation.

Animals↗

Morphogenesis and fibronectin in sexual differentiation of rat embryonic gonads.

The possible role of fibronectin in the organization of the sex-specific gonadal components was studied by immunocytochemistry combined with electron and light microscopy in rat fetuses at the ages of 12-15 days. Fibronectin was evenly distributed in both sexes under the basal lamina of the surface epithelium. Other basal laminae were not seen using light or electron microscopy inside the gonadal ridges at the age of 12 days. As the first sign of sexual differentiation, fibronectin-negative gonadal cords appeared in 13-day-old fetuses. In the males the cords were bigger than those in the females. The cords were clearly separated from the interstitium in 15-day-old fetuses of both sexes. A continuous layer of fibronectin had formed between the testicular surface epithelium and the elongated cords indicating the formation of a tunica albuginea. In females the surface epithelium-cord connection was maintained at all stages. Connections of the gonadal cords to mesonephric tubuli were seen in the rete region of both sexes. The electron optical basal lamina around the gonadal cords became continuous by the age of 15 days. The present results suggest that fibronectin is intimately involved in the sexual differentiation of the gonads, but not under the regulation of H-Y antigen or other testis-organizing factor.

Animals↗

Morphology and innervation of a testicular 'rete mirabile' in the guinea-pig.

The morphology and innervation of the testicular artery and pampiniform plexus of the guinea-pig was investigated using light immunohistochemistry as well as transmission and scanning electron microscopy. The tortuous, spiraled testicular artery embedded within the epididymal fat pad is totally encompassed by a thin-walled sinus-like labyrinthine structure comprising the pampiniform plexus. Characteristic features of this lacunar system are: 1. Endothelial bridges, strands or trabeculae of various length, width and thickness which project into the lumen, occasionally branch, and attach to the opposite or adjacent area of the venous wall. 2. A frequent discontinuous smooth muscular layer. Nerve fibers were localized by use of antibodies against dopamine-beta-hydroxylase (DBH-IR), neuropeptide Y (NPY-IR), and substance P (SP-IR). A great abundance of NPY-IR and DBH-IR axon bundles are seen surrounding the testicular artery. Fibers emanating from this dense plexus travel into the interstitium to finally innervate the walls of the sinus-like system, including the cross-luminal trabeculae. In contrast, larger varicosities are distinctive for SP-IR fibers which are also located at the media-adventitia border of the arterial and venous walls but to a far lesser extent than that seen with DBH-IR or NPY-IR. The axon varicosities supplying the arterial and venous walls contain a heterogeneous population of various types of vesicles, mostly including small agranular and granular ones as well as large granular vesicles of various size and density. The most conspicuous feature concerning the innervation pattern of the venous wall is the occurrence of numerous neuroendothelial contact zones. The findings of the investigated 'rete mirabile' are discussed with respect to rheology and temperature control for the maintenance of normal spermatogenesis.

Animals↗

Expression of calretinin in human ovary, testis, and ovarian sex cord-stromal tumors.

Calretinin, a calcium-binding protein, is primarily expressed in certain subtypes of neurons. It has also been found to be present in mesothelial cells and mesotheliomas but not in many types of carcinomas. Using a polyclonal anti-calretinin antibody, we investigated the expression of calretinin immunohistochemically in nonneoplastic human ovaries and testes and ovarian sex cord-stromal tumors (SCSTs). In ovaries, calretinin was expressed in theca interna cells, hilus cells, and scattered individual stromal cells. Oocytes, granulosa cells, theca externa cells, rete ovarii, and most stromal cells were negative. Expression of calretinin was also seen in the ovarian surface epithelium and in collapsed and flat epithelial inclusion glands (EIGs), but not in round, columnar, and ciliated EIGs. In some glands, a transition from calretinin-positive to calretinin-negative epithelium was observed. In postpubertal testes, calretinin was expressed in Leydig cells, but not in germ cells or most rete testes and Sertoli cells. In ovarian SCSTs, strong calretinin staining was seen in all hilus cell tumors (4/4) and the Leydig cell component of Sertoli-Leydig cell tumors (10/10). The Sertoli cell component showed focal weak positivity in 5/10. Fibrothecomas were completely negative (0/8). In granulosa cell tumors, the tumor cells were either completely negative (8/14) or weakly positive at the periphery of the tumor (6/14) while scattered stromal cell staining was seen in 9/14 cases. The expression of calretinin in normal Leydig cells, theca interna cells, the Leydig cell component of Sertoli-Leydig cell tumors, and hilus cell tumors suggests its functional relationship with androgen production. Its pattern of expression in ovarian SCSTs is useful in the differential diagnosis of these tumors. The presence of a transition from calretinin-positive, flat, nonciliated epithelium to calretinin-negative, columnar, ciliated epithelium in the same glands provides strong evidence for mullerian metaplasia.

Calbindin 2↗

Early differentiation of the testis in the native cat, Dasyurus viverrinus (Marsupialia).

The development of the testis in the native cat Dasyurus viverrinus (Marsupialia) is described, from Day 3 to 2.5 months post partum. The gonad rudiment consists of a mass of undifferentiated blastema cells of mesenchymal origin. The primordial germ cells populate the rudiment around the neonatal period. On Day 3 two cell types autodifferentiate from the gonadal blastema (pre-Sertoli and stroma cells) and the tunica albuginea begins to form. Pre-Sertoli cells are large, pale, cells which encompass the primordial germ cells and come to form a zone just beneath the tunica albuginea. By the end of the second week the cell complex has become transformed into a series of sex cords which encircle the gonad rudiment peripherally and converge on the rete cord in the hilar region. The stroma cells are fibroblast-like cells and occupy the central portion of the rudiment; by the eighth week, Leydig cells are appearing among them. No evidence was found for mesothelial invaginations or mesonephric contributions to the gonad. The classically recognised regions of 'cortex' and 'medulla' cannot be recognised and the seminiferous tubules differ in arrangement from that in eutherians.

Aging↗

Regulation of androgen and estrogen receptors in male excurrent ducts of the goat: an immunohistochemical study.

BACKGROUND: Since androgens and/or estrogens must bind with specific receptors in order to elicit a response at the target organ(s), it is important to understand factors that regulate expression of androgen receptors (AR) and estrogen receptors (ER). Hence, the objective of the study is to determine the relative significance between circulating androgen (CA) and luminal androgen (LA) in maintaining normal expression of AR and ER in male excurrent ducts. METHODS: Mature Nubian goats were subjected for 15 days each to the following treatments: (1) bilateral orchidectomy, (2) bilateral orchidectomy and testosterone treatment, (3) unilateral ligation of the extratesticular rete, and (4) unilateral orchidectomy. Tissues from different segments of the excurrent ducts were fixed in 4% paraformaldehyde and embedded in Paraplast-plus. Antigenic sites for AR and ER were immunolocalized using PG-21 rabbit antirat/human antibody and H-222 rat antihuman monoclonal antibody, respectively. The avidin-biotin horseradish peroxidase procedure was used to identify positive immunoreactivity. Negative controls included incubation of sections with irrelevant IgG in place of primary antibody. RESULTS: In intact animals, whereas AR were found in epithelial, connective tissue, and peritubular smooth muscle cells of the efferent ductules, regions I-V of the epididymis, and ductus deferens, ER were confined to nonciliated cells of the efferent ductules. Bilateral orchidectomy caused a severe loss of both AR and ER staining. Testosterone replacement to orchidectomized animals restored staining of both AR and ER to the intact level. Neither unilateral ligation of the extratesticular rete nor unilateral orchidectomy had any effect on AR or ER immunostaining. CONCLUSION: Circulating androgen alone, without any input from luminal androgen or other rete fluid contents, can regulate expression of both androgen receptor and estrogen receptor.

Animals↗

Origin of somatic cells and histogenesis in the primordial gonad of the Japanese tree frog Rhacophorus arboreus.

Gonadal development in Rhacophorus arboreus, a sexually semidifferentiated type of tree frog, was observed by means of the electron microscope, and cell proliferation kinetics were examined autoradiographically. The genital ridge consisted of coelomic epithelial cells and primordial germ cells. The gonadal medulla was formed by the segregation of epithelial cells within the primordial gonad. Thereafter, the medullary cell mass was well developed and oogenesis began in the gonadal cortex, irrespective of genetic sex. During metamorphosis, the ovarian cavity was formed in the medullary mass. This ovarian structure developed further in females. In males, on the other hand, a layer of medullary cells comprising the epithelium of the ovarian cavity proliferated rapidly and reformed a large cell mass. The degeneration of ovarian follicles and the formation of cell cords (rudimentary seminiferous tubules) were seen in the cortex. These cell cords were separated from the superficial epithelium and continued to the medullary mass (rudimentary testicular rete). These results clearly indicate that both the cortical and medullary cells are derived from the coelomic epithelium and that the development of the cortex and medulla is not always antagonistic in the course of sexual differentiation.

Animals↗

[New diagnostic procedures in assessing male fertility].

In 160 patients with normal and pathological semen samples, we studied the penetration of human spermatozoa in standardized bovine cervical mucus (assay Penetrak). Our results indicate that Penetrak can detect those dysfunctions of sperm motility which cannot be diagnosed by conventional semen analysis - The toluidine blue-pyronine staining is an easy way to differentiate between spermatozoa within an hour. The reliability of this technique is comparable to that of conventional methods and therefore appropriate for routine diagnostics. - As case studies on 140 patients proved, the level of carnitine in the seminal plasm can be regarded as a parameter of epididymal function. In combination with the examination of FSH serum levels, this method may be helpful in the differential diagnosis of azoospermia due to obstruction, Sertoli-cell-only syndrome, or spermatogenic arrest. - In severe oligozoospermia, testicular biopsy using semithin sections may be of high diagnostic and prognostic value. In contrast to paraffin sections, this technique is particularly appropriate for the detection of cytological characteristics of germ cells. The type and number of pathological germ cells are decisive regarding the prognosis. Furthermore, a carcinoma in situ (CIS) can be definitely identified by means of semithin sections. - In a study on 2047 patients, we found seminoma cells in 15 cases (0.73%); 5 of these patients already had a solid seminoma in the testicular rete. Risk-patients are those showing oligozoospermia of less than 10 million spermatozoa per ml or azoospermia associated with unilaterally or bilaterally subnormal testicular volume. In these cases, the testicles are inconspicuous, both palpatorically and sonographifically.

Biopsy↗

Sterilization of dogs with intra-epididymal injection of zinc arginine.

Condoms and vasectomy are the only fertility control methods available to males. Fifty million surgical vasectomies have been performed worldwide. In spite of improvements in the surgical techniques, the widespread use of vasectomy is limited due mainly to fear of genital operation. Chemical sterilization offers a promising new approach as an alternative to surgery. Fifteen sexually mature, mixed breed, male dogs, 2-3 1/2 years of age and weighing 22 +/- 1.8 kg, were divided into two groups. Five control placebo animals were injected with 0.5 ml of saline into the cauda epididymis, and ten treated animals were injected with 0.5 ml of 50 mg of zinc arginine into the cauda epididymis. Semen analysis performed before injection showed no significant difference between control placebo and treated groups. The control placebo animals exhibited a significant reduction in sperm motility one month after injection, which returned to normal within two months, and no change in semen volume, sperm abnormalities, or sperm concentration analyzed monthly for twelve months. The zinc arginine-treated animals achieved azoospermia ninety days after injection. The dogs were sacrificed one year after injection. There was no significant reduction of reproductive organ weights of the treated group as compared to the control placebo group. Although histological examination of the testes revealed normal seminiferous tubules, there was atrophy of the rete testes of the zinc arginine-treated group and, thus, increase in connective tissue. Histological examination of epididymides of the zinc arginine-treated group indicated that none of the cells in the head, body, and tail of the epididymis and ductus deferens contained sperm; 90% of the coils were empty and 10% contained amorphous pink cell debris; the coils decreased in diameter and were lined by cuboidal to columnar epithelium; no granuloma was observed. There was no significant change in serum testosterone level of control placebo and treated groups. These results offer the possibility of a new method of permanent sterilization instead of surgery. Zinc is considered to be nonmutagenic, noncarcinogenic, and nonteratogenic.

Analysis of Variance↗

Intermediate filaments and epithelial differentiation of male rat embryonic gonad.

The presence and distribution of desmin, vimentin, cytokeratin, and laminin in the gonads of developing male rat embryos (11-17 days) were studied by immunocytochemistry. The findings were correlated with morphological changes of the cells and with the formation of basement membranes, as determined by electron microscopy. The surface epithelial and subepithelial cells of the meesonephros in the prospective gonadal region contained desmin. At the onset of gonadal development, vimentin appeared in the somatic cells of the thickening surface epithelium, which formed the gonadal ridge. Desmin disappeared and cytokeratins appeared in the Sertoli precursor cells at the inception of their epithelial differentiation. Simultaneously, the prospective Sertoli cells became polarized during their assembly into epithelial cell aggregates; the aggregates then fused and formed elongated testicular cords. The epithelial cell differentiation was accompanied by a deposition of basement membrane material around the cords and by an increase of desmin in the cells immediately around the cords. With further differentiation of the testicular cords, some cytokeratins from the Sertoli cells, but not from the cells of the rete cords, disappeared. On the other hand, other cytokeratin polypeptides and vimentin remained in the fetal Sertoli cells. The surface cell layer slowly differentiated towards a proper epithelium after the basic formation of the testicular cords and interstitium. Desmin and vimentin persisted in the interstitial cells throughout the entire study period. The early differentiation of the gonad is apparently under a general sex-independent initiation program. The developmental changes in intermediate filaments offer an opportunity for the further analysis of their general role in early organogenesis. In light of the genetic theory of testicular differentiation, the functions of the regulatory factor(s) include specific organization of cord cells, histological organization into looping cords rather than separated follicles, and male development of the interstitium, surface epithelium and tunica albuginea.

Animals↗