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Secondary Spermatocytes (secondary + spermatocyte)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Localizations of intracellular calcium and Ca2+ -ATPase in hamster spermatogenic cells and spermatozoa

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 8 2006
H.L. Feng
Abstract Calcium plays a predominant role regulating many functional processes of spermatogenesis and fertilization. The purpose of the present study is to define the exact location of calcium as well as examine the role it plays during spermatogenesis and sperm capacitation. Testes and epididymides were obtained from adult healthy male hamsters. Spermatozoa were incubated with modified Tyrode's medium up to 4 h at 37°C for sperm capacitation in vitro. Samples of the testes and sperm cells were analyzed by cytochemical techniques to determine the location of calcium and Ca2+ -ATPase and the percentage of acrosome reactions under light and electron microscopy. The data showed that (1) Sertoli cells exhibited numerous calcium precipitates as large, round, electron-dense bodies distributed throughout the cytoplasm and the mitochondrial matrix. Fine calcium precipitates existed in fewer numbers in the intracellular storage sites of spermatogonia and primary spermatocytes, in sharp distinction to secondary spermatocyte and spermatids, which showed an abundance of large and round calcium precipitates, especially in the mitochondrial matrix of spermatids. More calcium deposits were distributed in the plasma membrane (PM), acrosome membrane, and matrices of the acrosome and mitochondria following capacitation; (2) Ca2+ -ATPase was found in the endoplasmic reticulum system and PM of noncapacitated spermatozoa as well as Sertoli cells. Capacitated spermatozoa showed a weak signal. These results suggest that the presence of calcium in spermatogenic cells might play a role in cell growth and differentiation during spermatogenesis. The Ca2+ -ATPase function may be inhibited during capacitation, leading to an increase in acrosomal calcium level and triggering of acrosomal exocytosis. Microsc. Res. Tech., 2006. © 2006 Wiley-Liss, Inc. [source]

A histo-morphological study of the testis of the sharptooth catfish (Clarias gariepinus) as reference for future toxicological assessments

JOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2008
J. C. Van Dyk
Summary The sharptooth catfish (Clarias gariepinus) has recently been shown to be a useful indicator species of oestrogen polluted waters in South Africa (Barnhoorn et al., 2004). Knowledge of the normal reproductive biology of this species is important to be able to assess the morphological changes caused by the exposure to potentially harmful toxicants including endocrine disruptor chemicals (EDCs). Eleven sexually mature C. gariepinus males were selected from an aquarium population bred through hormone induced spawning in reconstituted reverse osmosis water. The fish were reared under controlled conditions averting exposure to potentially EDCs and allowing the description of the normal testis histomorphology of unexposed healthy specimens. The testes of C. gariepinus are paired elongated organs situated in the dorsal region of the visceral cavity. Histologically, the testes possess a lobular organization enclosed by a thin tunica albuginea. Depending on the tissue region, each seminiferous lobule contains some or all of the various developmental stages of spermatogenesis including a single primary spermatogonia, groups of secondary spermatogonia, cysts of primary and secondary spermatocytes, spermatids, and spermatozoa. Nutritive Sertoli cells are visible on the periphery of the seminiferous lobules. Interstitial tissue (including groups of Leydig cells) and blood vessels constitute most of the interlobular space. It is expected that the histological results of this study will contribute to a currently limited, but growing gonadal histological database for southern African freshwater fish species to serve as reference in future toxicity assessments. [source]

Effect of textile waste water on the spermatogenesis of male albino rats

JOURNAL OF APPLIED TOXICOLOGY, Issue 3 2003
R. S. Gupta
Abstract Textile waste water released from dyeing and printing industries situated in Sanganer, Jaipur (India), brought about inhibition of spermatogenesis in male rats. Water analysis showed the presence of heavy metals at more than permissible limits. Oral administration of waste water to the rats at the dose level of 26.6 ml kg,1 body wt. significantly reduced the weights of testes, epididymides and seminal vesicle. Treated animals showed a notable depression of various stages of spermatogenesis. The production of spermatids was inhibited by 70.8% in waste-water-treated rats. The populations of spermatogonia, preleptotene spermatocytes and secondary spermatocytes were decreased by 67.2, 71.1 and 73.2%, respectively. The total number of Sertoli cells was affected after waste water treatment. Reduced sperm count and motility resulted in treated groups. A significant fall in the content of various biochemical parameters of reproductive tissues was observed after water treatment. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Effect of Mucuna urens (horse eye bean) on the gonads of male guinea-pigs

PHYTOTHERAPY RESEARCH, Issue 2 2001
Paul Udoh
Abstract The effect of Mucuna urens (seeds) on the gonads and sex accessory glands of male guinea-pigs was investigated. Sexually mature guinea-pigs of proven fertility were administered orally with 70,mg/kg and 140,mg/kg body weight of crude extract daily for 8 weeks respectively. Phytochemical screening of the seeds revealed the presence of alkaloids. No death or weight loss were observed during the duration of treatment. No pregnancy occurred in females mated with the treated males. Histological observations at high dose (140,mg/kg) showed complete degeneration of sperm in the testicular tubules. In some tubules, the acrosomal cap of the sperm cells was separated from the nuclei which underwent colour changes. In some tubules only the tails were left in the lumen. The spermatids, primary and secondary spermatocytes showed pycnosis while the morphology of spermatogonia and germinal epithelium appeared normal. Some epididymides were devoid of sperm while others contained degenerated spermatozoa and cell debris. In the prostate gland there was collapse of the villi and reduction of secretion in both the prostate and seminal vesicles. At low doses (70,mg/kg), there was spermatogenic arrest at spermatid stage. These observations have shown that M. urens is a potential male antifertility agent. Copyright © 2001 John Wiley & Sons, Ltd. [source]