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At least 685 records · Page 38Linked to original sources
PubMed1995

Endocrine control of testicular somatic and premeiotic germ cell development in the immature testis of the primate Macaca mulatta.

Four groups(N = 3 per group) of juvenile rhesus monkeys (Macaca mulatta, 14-20 months old) received either vehicle or highly purified human follicle-stimulating hormone (FSH; 10 IU kg-1 day-1), human chorionic gonadotropin (hCG; 250 IU every alternate day) or both hormones for a period of 4 weeks. Testicular volume and weight increased more than twofold after single and more than sixfold after combined hormone treatment. Serum and intratesticular testosterone were at supraphysiological levels in hCG-treated animals and rose even more after combined treatment; a minor elevation of intratesticular testosterone was also observed after FSH treatment. Serum inhibin was elevated after hCG or FSH treatment and increased more than twofold during the first 3 weeks of combined treatment. Semiquantitative analysis of cell numbers showed a statistically non-significant increase in Sertoli cells and Ad- and Ap-spermatogonia after single hormone treatment. Combined treatment induced a further increase in the number of spermatogonia. Leydig cells were only encountered after hCG treatment; their number was more than threefold higher after combined treatment compared with hCG alone. Follicle-stimulating hormone stimulated Sertoli cell and Ap spermatogonia proliferation but did not induce morphological differentiation of Sertoli cells, peritubular cells or Leydig cells. Human CG treatment, however, induced Sertoli cell proliferation and morphological differentiation. It had effects on spermatogonial proliferation but induced differentiation of peritubular cells. Combined treatment initiated the greatest morphological and functional differentiation of Sertoli cells, peritubular cells, Leydig cells and spermatogonia. Flow cytometric analysis confirms an increase of mitotically active cells. The observations show that FSH and testosterone can induce Sertoli cell proliferation. Morphological differentiation of Sertoli cells may be mediated indirectly by environmental and paracrine stimuli released from peritubular cells, whose differentiation is androgen dependent. Leydig cells are stimulated mainly by hCG. Our present and previous data lead us to propose that FSH contributes to the final number and activity of Leydig cells, which secrete immunoreactive inhibin in response to hCG.(ABSTRACT TRUNCATED AT 400 WORDS)

Actins↗
PubMed1992

False-negative biopsy for testicular intraepithelial neoplasia.

A routine biopsy of the contralateral testis obtained during orchiectomy for embryonal carcinoma in a 26-year-old patient was negative for testicular intraepithelial neoplasia (TIN; carcinoma in situ of the testis). However, a rebiopsy that was taken because of unexplained elevation of alpha-fetoprotein 15 months later proved to be positive for TIN. Six previously reported cases of false-negative testicular biopsies obtained during a search for TIN are reviewed. In the light of several thousands of biopsies performed world-wide to date, the number of false-negative biopsies is probably very low. Although TIN is obviously not randomly dispersed throughout the testis in all patients, a routine biopsy of the contralateral testicle in patients with testis cancer remains a valuable tool for early detection of bilateral testicular tumors.-cal distribution of TIN in testes removed for this lesion. Their results suggested that after puberty TIN is usually randomly dispersed throughout the testicle. Support for this concept was recently given by Mumperow et al. (1992). These authors examined tumor-bearing testes and they did not find differences in the presence of TIN in biopsies taken from a location close to the tumor and taken from a location distant from the tumor. Thus, one single biopsy is regard to be representative for the entire testis and one biopsy taken after puberty is also assumed to be reliable for predicting whether the testis will ever develop cancer (Berthelsen and Skakkebaek 1981 a). Conversely, if the biopsy is negative for TIN, a future tumor manifestation in the testicle examined is not expected according to this theory (Skakkebaek et al. 1987). Taken together, the concept of TIN would constitute an ideal avenue for the early detection of testis cancer in high-risk populations with the biopsy being a safe means of discriminating between individuals who will or who will not develop testis cancer.

Adult↗
PubMed1978

The development of Schistosoma haematobium in the hamster.

The in vivo development of Schistosoma haematobium in the hamster was studied. Six stages of development were distinguished on the basis of morphological and histochemical criteria. Schistosomula reached the lung (stage 1) on day three post-infection, with maximum concentrations on day nine. Gut formation occurred in the second stage at day 18. In stage 3 'Organogeny' (day 24) males developed one testis and females a narrow uterus. Pairing and the development of males with sperm-containing testes and females with an ovary characterize stage 4 (day 28). In stage 5 (day 53) vitelline follicles begin to develop in the females. The final stage, oviposition, occurred on days 61-63 and was characterized by the appearance of fully developed eggs in the uterus.

Animals↗
PubMed2004

[Morphological studies on embryonic gonad development in Kunming mice].

OBJECTIVE: To observe the morphological changes of embryonic gonad in Kunming mice in different developmental stages. METHODS: HE stained paraffin sections of the embryonic mouse gonads in different developmental stages were prepared for evaluation of the morphological changes. RESULTS: The genital ridge was identified on the 11th day after the mating and undifferentiated gonad detected on the 12th day, while 1 d later, sexual identification was possible by examining the sections. The male gonad developed into testis by forming seminiferous tubules and Sertoli cells on the 14th day. On the 16th day, the female gonad evolved into the ovary with obvious differentiation of the cortex and medulla and till the 20th day, more seminiferous tubules occurred in the testis with cavities containing numerous spermatogenic cells at different developing phases; also observed was a mass of rough sex cords that produced ovarian follicles surrounding the ovary and contained large quantity of primitive oogonia. CONCLUSIONS: Days 11-12 after mating might be the best time for separating primordial germ cells from undifferentiated mouse gonad.

Animals↗
PubMed2006

Building a testis: formation of functional testis tissue after transplantation of isolated porcine (Sus scrofa) testis cells.

During mammalian development, morphogenesis of the testis requires the coordinated interplay of somatic cells to form seminiferous cords in which the primitive germ cells reside. These cords are the precursor of the functional male gonad and as such form the basis of male fertility. Cell migration during mammalian organogenesis and formation of complex tissues, such as the testis, are difficult to study in situ. Herein, we report extensive rearrangement of cells to regenerate complete functional testis tissue after implantation of isolated neonatal porcine testis cells under the skin of immunodeficient mice. Somatic cells and germ cells reorganized into structures that have remarkable morphologic and physiologic similarity to normal testis tissue, forming the endocrine and spermatogenic compartment of the testis. This unique in vivo system provides an accessible model for the study of testicular morphogenesis that could be especially useful in nonrodent species.

Animals↗
PubMed2002

Temporal changes in testis weight during the past 50 years in Japan.

The ever-increasing presence of environmental toxicants and their disruptive effect on the reproductive systems of wildlife raises the question of possible damage to the human reproductive system. Using medicolegal data from over 20,000 Japanese men subjected to necropsy from 1948 to 1998, we investigated temporal changes in testis weight to find possible evidence of male reproductive disorders. We also carried out a histological examination of 747 testes collected from 1978 to 1998. Our detailed analyses of the development of testis weight over the past 50 years have revealed four clear phenomena: (i) the age at which testis weight reaches its maximum has decreased; (ii) peak weight showed a general increase until it started to decline in boys born after 1960; (iii) the decline-rate at which testis weight decreases after its peak has greatly accelerated; and (iv) the onset of increasing testis weight of boys has occurred at a progressively younger age. Our quantitative analyses of testis weight indicate the possibility of a subtle reproductive disorder in Japanese men, especially in those born after 1960. Together with the accelerated development and decline in testis weight during the past 50 years, the decline in peak weight might be indicative of a subtle interference of environmental toxicants with male reproductive organogenesis.

Adolescent↗
PubMed1995

Expression of mRNA and immunocytochemical localization of inhibin alpha- and inhibin beta A-subunits in the fetal sheep testis.

In order to investigate the ontogeny of gonadal inhibin production in the male fetal sheep, testes were collected from male fetuses at days 70, 100, 130 and 140 of gestation (term = 145 days). The expression and localization of inhibin alpha- and inhibin beta A-subunit mRNA and protein were evaluated using in situ hybridization and immunocytochemistry. The expression of inhibin alpha-subunit mRNA was localized within the seminiferous cords of the developing fetal testis and progressively increased with gestational age. Immunostaining corresponding to immunoreactive inhibin alpha-subunit was detected in Sertoli cells within the seminiferous cords at days 100, 130 and 140 of gestation. In addition, immunostaining was detectable in a small proportion of Leydig cells. No expression of inhibin beta A-subunit mRNA or immunoreactivity was detected in any testicular tissue at any stage of gestation. These data show that the Sertoli cells of the developing fetal sheep testis have the capacity to produce inhibin alpha-subunit by day 100 of gestation and that production increases during late gestation.

Animals↗
PubMed1989

Corticosteroid 11 beta-dehydrogenase in rat testis.

Corticosteroid 11 beta-dehydrogenase, the enzyme that catalyzes the oxidation of the biologically active steroid cortisol to its inactive metabolite cortisone, is present in testis. Since excess cortisol in men and other mammals and excess corticosterone in rodents cause physiological abnormalities including abnormal testicular function, it was pertinent to study the cellular distribution of 11 beta-dehydrogenase in the testis. Purified antiserum directed against homogeneous rat 11 beta-dehydrogenase was used to localize the enzyme in the developing rat testis. With immunofluorescence, the enzyme was not detectable in fetal testis or in the testis of young male rats until the 26th day of development. A few interstitial cells were stained in the testis of 26-day-old animals. In the testis of 31-day-old rats many cells in the interstitium were positive. In adult animals the entire interstitial region displayed bright fluorescence. Depleting animals of germ cells did not abolish the fluorescence. The appearance of this enzyme correlates temporally with the postnatal increase in Leydig cell number and the developmental rise in serum testosterone. We suggest that 11 beta-dehydrogenase of Leydig cells protects the testis from the deleterious effects of cortisol.

11-beta-Hydroxysteroid Dehydrogenases↗