نتایج جستجو برای: bovine spermatogonia
تعداد نتایج: 75109 فیلتر نتایج به سال:
While it is known that retinoic acid (RA) induces meiosis in mouse female fetal gonads, the mechanisms which regulate this process during spermatogenesis are poorly understood. We show that the All trans RA derivative (ATRA) and Kit Ligand (KL) increase meiotic entry of postnatal mouse spermatogonia in vitro without synergism. Competence to enter meiosis is reached by spermatogonia only at the ...
BACKGROUND Adult patients with idiopathic hypogonadotropic hypogonadism (IHH) typically present with absent puberty and therefore have prepubertal testes. IHH is recognized as one of the few curable causes of male infertility and is often effectively treated with either gonadotropins or pulsatile GnRH therapy. The objective of this study was to determine the structure of the testis prior to ini...
Mumps commonly affects children 5-9 yr of age, and can lead to permanent adult sterility in certain cases. However, the etiology of this long-term effect remains unclear. Mumps infection results in progressive degeneration of the seminiferous epithelium and, occasionally, Sertoli cell-only syndrome. Thus, the remaining Sertoli cells may be critical to spermatogenesis recovery after orchitis hea...
Meiosis is an indispensable process of sexual reproduction. However, detailed information on the regulatory mechanisms that initiate meiosis is not available. Progestins are important steroids regulating final maturation in male and female vertebrates. In male teleosts, it is known that progestin induces spermiation and sperm maturation. However, a role for progestin in early spermatogenesis or...
Phthalate esters are plasticizers that impart flexibility to polvinylchloride plastics. As they are not covalently bound, they can leach from a wide range of products, including food containers, medical devices, clothing, and toys, leading to widespread environmental exposure. Phthalate toxicity has been linked to male infertility by disrupting testosterone production and testis development. Ph...
Despite timely and successful surgery, 32% of patients with bilateral and 10% with unilateral cryptorchidism will develop azoospermia. Cryptorchid boys at risk of azoospermia display a typical testicular histology of impaired mini-puberty at the time of the orchidopexy. During mini-puberty increased gonadotropin and testosterone secretion stimulate transformation of gonocytes into Ad spermatogo...
The spermatogonia and early spermatocytes of 13 samples of rat seminiferous epithelium (about 0-05 mm2 each) were mapped from electron micrographs of serial sections. Clones of cells, connected by cytoplasmic bridges (syncytia of 2-100 cells), in various stages of spermatogenic development were identified. Maps of 7 separate areas are illustrated. It is concluded that, contrary to the models of...
A quantitative analysis of germ-cell populations in normal, hypophysectomized (Hx), and Hx-hormone-treated animals was undertaken during periods of regression that were characterized as intermediate, between short-term and long-term regression of the testis. Twenty-one groups of adult rats were administered either follicle-stimulating hormone (FSH), growth hormone, thyroid-stimulating hormone (...
In this review, we aim to examine the effect of extrinsic and intrinsic factors on spermatogenesis process taking into account a complex signaling pathway. Primarily, it is suggested that retinoic acid (RA) has a vital function in spermatogenesis process and it is considered to be essential for completion of spermatogonia into mature spermatozoa. In the present review, the key effects of retino...
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