نتایج جستجو برای: leydig

تعداد نتایج: 3705  

Journal: :Endocrinology 1998
R S Ge M P Hardy

The amount of testosterone (T) secreted by Leydig cells is determined by a balance between T biosynthetic and metabolizing enzyme activities. It has been established that 5alpha-androstan-3alpha,17beta-diol (3alpha-DIOL) is the predominant androgen secreted by the testes of immature rats during days 20-40 postpartum, whereas T is the major androgen by day 56. However, the underlying changes in ...

Journal: :Journal of cell science 2002
Peter J O'Shaughnessy Heather Johnston Louise Willerton Paul J Baker

During testicular development, fetal and adult populations of Leydig cells arise sequentially. Previous studies have shown that androgen action is required for normal steroidogenic activity in the mouse testis. Therefore, to determine the role of androgens in regulating fetal and adult Leydig cell differentiation and function, Leydig development has been measured in mice lacking functional andr...

Journal: :Journal of andrology 1997
R J Duckett N G Wreford S J Meachem R I McLachlan M P Hedger

The objective of this study was to investigate the role of androgens and nonandrogenic Leydig cell products in maintaining Leydig cell and macrophage numbers in the testis of the adult rat. Adult male Sprague-Dawley rats received Silastic implants containing testosterone and estradiol (T-E) in order to suppress endogenous luteinizing hormone (LH) for 9 weeks. After T-E treatment, Leydig cell an...

Journal: :Asian journal of andrology 2006
Qian Wang Hui-Bao Gao

AIM To investigate the activation of nuclear factor-kappa B (NF-kappa B) and its function in glucocorticoid-induced Leydig cell apoptosis. METHODS The Leydig cells were isolated from male Sprague-Dawley rats (90 days of age) and were incubated with corticosterone (CORT, glucocorticoid in rat) for 6 h, 12 h and 24 h, respectively. The P65 subunit of NF-kappa B (NF-kappa B/P65) in nuclei and th...

Journal: :Cancer research 2005
Sabrina Basciani Marina Brama Stefania Mariani Gabriele De Luca Mario Arizzi Loredana Vesci Claudio Pisano Susanna Dolci Giovanni Spera Lucio Gnessi

Leydig cell tumors are usually benign tumors of the male gonad. However, if the tumor is malignant, no effective treatments are currently available. Leydig cell tumors express platelet-derived growth factor (PDGF), kit ligand and their respective receptors, PDGFR and c-kit. We therefore evaluated the effects of imatinib mesylate (imatinib), a selective inhibitor of the c-kit and PDGFR tyrosine ...

Journal: :The Journal of clinical endocrinology and metabolism 1999
M P De Miguel J Regadera F Martinez-Garcia M Nistal R Paniagua

The immunohistochemical reaction to oncostatin M (OSM) was studied in normal human testes at different ages (fetuses, newborns, children, pubertal boys, adults, and elderly men), as well as in several testicular disorders including carcinoma-in-situ cells (CIS), germ cell tumors, benign functioning Leydig cell tumor, androgen insensitivity syndrome, Klinefelter's syndrome, and cryptorchidism. P...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1999
H Chen B R Zirkin

Male aging is accompanied by reduced testosterone production by the Leydig cells, the testosterone-producing cells of the testis. The mechanism by which this occurs is unknown. Based on the observations that reactive oxygen is capable of damaging components of the steroidogenic pathway and that reactive oxygen is produced during steroidogenesis itself, we hypothesized that long-term suppression...

Journal: :Advances in anatomy, embryology, and cell biology 2009
Michail S Davidoff Ralf Middendorff Dieter Müller Adolf F Holstein

The Leydig cells of the testis represent the main source of androgens. The idea of Leydig cells as endocrine cells has been the leading characteristic of this interesting cell population till now. Our studies of the last 2 decades allowed us to reveal a new important feature of Leydig cells that is their obvious similarity with structures of the central and peripheral nervous system. This inclu...

Journal: :The Journal of biological chemistry 1980
A H Payne K L Wong M M Vega

Luteinizing hormone (LH) receptor sites and in vitro testosterone production in response to human chorionic gonadotropin (hCG) stimulation (Leydig cell responsiveness) were studied in two distinct populations of Leydig cells after different modes of in vivo gonadotropin treatments. Dispersed cells from decapsulated rat testes were purified and separated into two distinct populations of Leydig c...

Journal: :Journal of andrology 1988
K J Teerds D G De Rooij F F Rommerts C J Wensing

The proliferation and differentiation of possible Leydig cell precursors in adult rats were studied after destruction of the existing Leydig cells with EDS or after daily treatment with hCG. After 2 days with either treatment, a 12- to 16-fold increase in the number of [3H]thymidine-incorporating interstitial cells was found. In the case of hCG treatment, this was probably due to the high plasm...

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