نتایج جستجو برای: leydig cells

تعداد نتایج: 1384711  

Journal: :Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas 2002
A C S Castro W E Berndtson F M Cardoso

Plasma and tissue testosterone concentrations were determined by radioimmunoassay in 12 eight-month-old sexually mature New Zealand White rabbits and evaluated for possible associations with spermatogenic efficiency as well as with volume density and number of Leydig cells. Testicular tissue was processed histologically and histometry was performed in order to quantify germ cells, Sertoli cells...

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: :Endocrinology 1999
M F Taylor M de Boer-Brouwer I Woolveridge K J Teerds I D Morris

Leydig cells undergo apoptosis in response to the cytotoxin ethane dimethanesulfonate (EDS), with numbers declining at 12-18 h and maximal apoptosis at 24 h postinjection. The Bcl-2 family members, Bcl-2, Bcl-xl, and Bax, appear not to be involved in this process. To further investigate this phenomena, a single dose of EDS was administered to adult rats to induce the killing of Leydig cells. Th...

Journal: :Reproduction, nutrition, developpement 1987
J P Fouquet M L Kann

The testes of the monkey, Macaca fascicularis, from birth to adulthood and of rats from puberty to adulthood were examined by both light and electron microscopy to estimate the mitotic activity of the Leydig cells. In monkeys, mitotic activity was measurable only in neonates: 2.3% in Leydig cells and 0.4% in fibroblast-like cells. From measurements of 3H-thymidine incorporation, mature Leydig c...

2014
Trpimir Goluža Alexander Boscanin Jessica Cvetko Viviana Kozina Marin Kosović Maja Marija Bernat Miro Kasum Zeljko Kaštelan Davor Ježek

A number of studies have indicated that testicular macrophages play an important role in regulating steroidogenesis of Leydig cells and maintain homeostasis within the testis. The current paper deals with macrophages (CD68 positive cells) and Leydig cells in patients with nonobstructive azoospermia (NOA). Methods employed included histological analysis on semi- and ultrathin sections, immunohis...

Journal: :The Journal of biological chemistry 1984
P G Quinn A H Payne

Cultured Leydig cells exhibited time-dependent decreases in the microsomal cytochrome P-450 enzyme activities, 17 alpha-hydroxylase and C17-20 lyase when maintained under standard culture conditions (95% air, 5% CO2). Inclusion of the hydroxyl radical scavenger dimethyl sulfoxide in the culture medium, or the reduction of oxygen tension from 19 to 1% O2 was effective in preserving these enzyme ...

Journal: :Asian journal of andrology 2005
Paul F Moundipa Nathalie Sara E Beboy Fabien Zelefack Silvére Ngouela Etienne Tsamo Wolf-Bernhard Schill Thomas K Monsees

AIM To determine the androgenic effects of Basella alba and Hibiscus macranthus extracts in the rat and the bull, and to develop a novel in vitro test system using Leydig cells from bull testes. METHODS The effect of methanol extracts from both plants on testosterone production in isolated Leydig cells from the rat and the bull was analyzed using 125I-radioimmunoassay (125I-RIA). Rat Leydig c...

Journal: :Journal of lipid research 2000
E Reaven L Zhan A Nomoto S Leers-Sucheta S Azhar

This study investigates the relationship between the high density lipoprotein (HDL) receptor (scavenger receptors, SR-BI and SR-BII), selective lipoprotein-cholesteryl ester uptake, and testosterone production in Leydig cells of control, hypocholesterolemic and gonadotrophic hormone (hCG) treated rats. Leydig cells from mature control rats show poor efficiency in incorporation of labeled HDL-ch...

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...

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