background: due to common use of methylphenidate (mph) for the treatment of attention deficit hyperactivity disorder (adhd) and the role of the reproductive system in the production of gametes, studying the effects of this medication on the morphometry of testes, serum testosterone concentration, leydig cells function, and fertility rate was the aim of this study. methods: twenty seven male mic...

Postnatal development of Leydig cells can be divided into three distinct stages of differentiation: initially they exist as mesenchymal-like progenitors (PLC) by day 21; subsequently, as immature Leydig cells (ILC) by day 35, they acquire steroidogenic organelle structure and enzyme activities but metabolize most of the testosterone they produce; finally, as adult Leydig cells (ALC) by day 90 t...

Testicular tumors are generally characterized by a loss of responsiveness to gonadotropins. The M5480 Leydig cell tumor is unusual, if not unique, in that it responds to human choriogonadotropin and to lutropin via increased steroidogenesis. This report describes the identification of two variants of the original M5480 tumor that have altered steroid output both in the basal state and in respon...

Although p-adrenergic control of another steroidogenic tissue, the ovary, has been established (Godkin et al., 1977; Jordan et al, 1978; Hunzicker-Dunn, 1980; Hunzicker-Dunn et al., 1979; Kliachko & Zor, 1981), there have been no reports that catecholamines can directly stimulate steroidogenesis in Leydig cells. During the course of our investigations on factors controlling Leydig activity in c...

The mechanism of phytoestrogen action in gonadal cells of ganders has not been elucidated. The aim of the study was to investigate in Biłgoraj ganders the possibility of phytoestrogen action via estrogen or androgen receptors or via protein tyrosine kinase pathways in Leydig cells. Genistein and daidzein (5 and 50 microM) as well as equol (50 microM) inhibited testosterone (T) secretion by incu...

Hematopoietic stem cell transplantation (HSCT) is associated with significant posttransplantation gonadotoxicity. This deficit has been mainly attributed to pretransplantation conditioning, but lower sperm counts in humans also appear to be associated with graft-versus-host disease (GVHD) following allogeneic HSCT. However, the mechanisms leading to diminished spermatocyte levels during GVHD re...

Using the antibody for glutathione S-transferase (GST) purified from human kidney, normal testes and experimental cryptorchid testes from newborn to 20-week-old rats were immunohistochemically stained by the peroxidase antiperoxidase (PAP) method. The cryptorchidism was surgically created at 1 week of age. The localization of GST was particularly examined by light microscopy, and the amount of ...

the influence of hypo- and hyper-thyroidism on spermatogenesis was studied in 60-day-old adult malewistar rats. to confirm hypo- and hyper-thyroidism, the concentration of plasma thyroid hormones wereassayed by radioimmunoassay. the hypothyroid state, induced by administration of 25 mg/kg/daymethimazole for 5 successive days, resulted in significant decrease in the number of sertoli cells, sper...

Glutathione S-transferases (GSTs), a family of isoenzymes, catalyze the conjugation of glutathione to a variety of electrophiles, and protect cellular constituents from electrophilic and oxidative attack. Aging is associated with an overall increase in oxidative stress and thus free radical production. The present study examines the immunocytochemical localization of Ya, Yc, Yb1, Yb2, Yo, and Y...

Strong overexpression of anti-Müllerian hormone (AMH) in transgenic mice leads to incomplete fetal virilization and decreased serum testosterone in the adult. Conversely, AMH-deficient mice exhibit Leydig cell hyperplasia. To probe the mechanism of action of AMH on Leydig cell steroidogenesis, we have studied the expression of mRNA for steroidogenic proteins in vivo and in vitro and performed a...