نتایج جستجو برای: bovine spermatogonia
تعداد نتایج: 75109 فیلتر نتایج به سال:
Human spermatogenesis includes three main stages, namely, the mitosis of spermatogonia, meiosis of spermatocytes, and spermiogenesis of spermatids, which are precisely regulated by epigenetic and genetic factors. Abnormality of epigenetic and genetic factors can result in aberrant spermatogenesis and eventual male infertility. However, epigenetic regulators in controlling each stage of normal a...
In newts elevated titers of plasma prolactin (PRL), induced by low temperature, cause apoptosis in the penultimatemitotic stage of spermatogonia, and this cell death is suppressed by antiserum against newt PRL, but only during the initial 3 days of exposure (Yazawa et al., 1999). Thus, factors other than PRL must be involved in spermatogonial death. Follicle-stimulating hormone (FSH) may be a p...
BACKGROUND The spermatogonial stem cell (SSC) pool in the testes of non-human primates is poorly defined. METHODS To begin characterizing SSCs in rhesus macaque testes, we employed fluorescence-activated cell sorting (FACS), a xenotransplant bioassay and immunohistochemical methods and correlated our findings with classical descriptions of germ cell nuclear morphology (i.e. A(dark) and A(pale...
The importance of gonadotropins and androgens for spermatogenesis is generally accepted in vertebrates, but the role played by specific hormones has not been clarified. Under cultivation conditions, male Japanese eels (Anguilla japonica) have immature testes containing only premitotic spermatogonia, type A and early-type B spermatogonia. In the present study, a recently developed organ-culture ...
In adult rhesus monkeys a two- to threefold increase in the number of spermatogonia was found at Day 75 after 1 Gy of X-irradiation when the animals were pretreated with two intramuscular injections of follicle-stimulating hormone (FSH) each day. Also the percentage of cross-sections of seminiferous tubules showing spermatogonia (repopulation index) was much higher when FSH was given before irr...
The recently discovered estrogen receptor-beta (ERbeta) is expressed in rodent and human testes. To obtain insight in the physiological role of ERbeta we have investigated the cell type-specific expression pattern of ERbeta messenger RNA (mRNA) and protein in the testis of rats of various ages by in situ hybridization and immunohistochemistry. In fetal testes of rats 16 days postcoitum and test...
The pattern of ribonucleic acid synthesis during germ cell development, from the stem cell to the mature spermatid, was studied in the mouse testis, by using uridine-H(3) or cytidine-H(3) labeling and autoradiography. Incorporation of tritiated precursors into the RNA occurs in spermatogonia, resting primary spermatocytes (RPS), throughout the second half of pachytene stage up to early diploten...
BACKGROUND Unilateral orchidectomy in monkeys increases spermatogenesis in the remaining testis in association with elevated follicle-stimulating hormone (FSH) secretion and testicular testosterone. The present study examined the relative importance of FSH and testosterone in driving the primate testis toward its spermatogenic ceiling. METHODS Adult male rhesus monkeys were treated with a gon...
Background Follicle stimulating hormone and testosterone stimulate Sertoli cells to support germ cell function and differentiation. During mini-puberty, when gonadotropin (GnRH) stimulates increases in plasma luteinizing hormone (LH) and testosterone levels, gonocytes are transformed into Ad spermatogonia. In cryptorchidism, impaired gonadotropin secretion during mini-puberty results in insuffi...
BACKGROUND AND AIMS In mammalian spermatogenesis, glial cell line-derived neurotrophic factor (GDNF) is one of the major Sertoli cell-derived factors which regulates the maintenance of undifferentiated spermatogonia including spermatogonial stem cells (SSCs) through GDNF family receptor α1 (GFRα1). It remains unclear as to when, where and how GDNF molecules are produced and exposed to the GFRα1...
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