Male reproductive system

The male reproductive tract consists of the (i) testes, which serve as the site of gamete and steroid hormone production, (ii) excurrant ducts and epididymes for the transport, maturation, and storage of sperm, (iii) accessory sex glands for the production of seminal fluid, and (iv) penis, for copulation and delivery of mature sperm to the female reproductive tract. 

Anterior and posterior pituitary are found together at the base of the skull, once the brain has been removed. The neurohypophyseal part (posterior pituitary) is discarded and the anterior pituitary is bisected to 

In addition to weight determination and histology, there are several available methods for obtained additional information about the site of action and mechanism of a change in androgen biosynthesis. 

The tissue content of the testis can be analysed by a several methods for androgens, either by a high-performance liquid chromatography (HPLC), or by specific radioimmunoassays for testosterone, progesterone, and the testosterone precursors in the biosynthetic pathway. 

Receptors in the testis for FSH and LH may be determined for specific investigations, but the information for risk assessment provided by this determination is limited. Incubation of the testis ex-vivo with human chorionic gonadotropin (hCG) is of considerable importance, and that biosynthesis of androgens may be assessed by measurement of the incubation media. 

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Finally, a new class of antispermatogenic agents containing the same fundamental structure cited above has been described (76JMC778). 1-Halobenzyl-l J/-indazole-3-carboxylic acids are potentially useful for birth control, and because they act after a single administration they are of interest for the physiological study of the male reproductive system. 

In addition to their endocrine disrupting properties, it must be appreciated that many of the chemicals in question possess more general toxic properties, which may be potentiated by metabolism by the organism. Several PAHs, PCBs and PCDDs are carcinogenic, while certain phthalate esters can enhance the excretion of zinc, potentially leading to zinc deficiency. Zinc, an essential element, plays a vital role in spermatogenesis and mature T-cell production. Deficiency may result in abnormalities of the male reproductive system, depletion of spermatogenesis and suppression of the immune system. 

Effects of Oestrogen on the Development and Function of the Male Reproductive System... 

SAUNDERS P T, SHARPE R M, WILLIAMS K, MACPHERSON S, URQUART H, IRVINE D S, MILLAR M R (2001) Differential expression of oestrogen receptor alpha and beta proteins in the testes and male reproductive system of human and non-human primates. Mol Hum Reprod. 7 227-36. 

Identify the structures of the male reproductive system and describe the physiology of a penile erection. 

Winer, M. A., and Wolgemuth, D. J. (1993). Patterns of expression and potential functions of proto-oncogenes during mammalian spermatogenesis. In The Molecular Biology of the Male Reproductive System (De Kretser, D. M., ed.), pp. 143-179. Academic Press, San Diego. 

Li P, Chan HC, He B et al. An antimicrobial peptide gene found in the male reproductive system of rats. Science 2001 291(5509] 1783—1785. 

Bernstein ME. 1984. Agents affecting the male reproductive systems Effects of structure on activity. Drug Metab Rev 15 941-996. 

V. Suryavati, S. Sharma, S. Sharma, P. Saxena, S. Pandey, R. Grover, S. Kumar and P.K. Sharma, Acute toxicity of textile dye wastewaters (untreated and treated) of Sanganer on male reproductive systems of albino rats and mice. Reprod. Toxicol., 19 (2005) 547-556. B. dos Santos, A.E. Bisschops, F.J. Cervantes and J.B. van Lier, The transformation and toxicity of anthraquinone dyes during thermophilic and mesophilic anaerobic treatments. J. Biotechnol., 115 (2005) 345-353. 

The direct effect of inhalation exposure to 1,2-dibromoethane on spermatogenesis in animals has not been studied. Nonetheless, the available data from animal studies indicate that the male reproductive system in rats is affected by exposure to 1,2-dibromoethane at high doses. In all studies discussed below, however, rats had high mortality associated with chemical toxicity and/or chemically-induced neoplasia. It is therefore difficult to attribute effects on the reproductive organs to... 

Following oral or intraperitoneal administration of heptachlor or heptachlor epoxide to male mice that were then bred with untreated females, the preimplantation losses and resorptions were within control limits (Arnold et al. 1977 Epstein et al. 1972). However, lack of corpora lutea counts may have resulted in inaccurate identification of preimplantation losses. On the other hand, when both sexes of mice or rats were fed diets containing heptachlor in multigeneration studies, resorptions were increased relative to controls, and fertility was markedly decreased (Green 1970), in some instances to zero (Akay and Alp 1981). These results seem to suggest that heptachlor affects the female reproductive system and/or the fetuses and may also affect the male reproductive system. 

The male reproductive system includes the two testes, ducts that store and transport the sperm to the exterior, and the glands that secrete into these ducts and the penis it also includes the hormones that integrate the reproductive activities. Basic details of the anatomy of the male reproductive system are given in Figures 19.1 and 19.2. 

Table 19.1 Compounds present in the secretions from various glands associated with the male reproductive system and their functions...

The Guidelines for Reproductive Toxicity Risk Assessment (US-EPA 1996) discuss the scientific basis for concern about exposure to agents that cause reproductive toxicity and describe the principles and procedures to be followed in conducting risk assessments for reproductive toxicity. They include the female (nonpregnant and pregnant) and male reproductive systems. 

Two major systems have been identified as toxicity targets for 1,3-DNB the red blood cell and the male reproductive system (see Section 2.2.2). In the red blood cell, 1,3-DNB induces formation of methemoglobin leading to cyanosis (Blackburn et al. 1988 Linder et al. 1988, 1990 Reader et al. 1991). In the male reproductive system, 1,3-DNB causes disruption of spermatogenesis resulting in hypospermia, poor sperm quality, and infertility (Blackburn et al. 1988 Hess et al. 1988 Linder et al. 1988). Whether adverse hematological and reproductive effects are caused by the same mechanism of action remains unresolved. 

Intermediate-Duration Exposure. No studies were located on intermediate-duration exposure to 1,3,5-TNB in humans or animals by any route. Therefore, studies in animals would provide useful information. There were also no studies on intermediate-duration exposure by any route to 1,3-DNB in humans. Studies in laboratory animals following intermediate-duration oral exposure to 1,3-DNB showed that a major target is the hematological system (see Section 2.2.2.2), but other targets include the central nervous system (Cody et al. 1981 Linder et al. 1986) (see Section 2.2.2.4) and the male reproductive system (Cody et al. 1981 Linder et al. 1986) (see Section 2.2.2.5). An intermediate oral MRL was derived for 1,3-DNB based on hematological effects in rats exposed for 12 weeks (Linder et al. 1986) (see Section 2.4). Studies to determine whether adverse effects occur in animals after inhalation or dermal intermediate duration exposure would be useful. 

No effects on the male reproductive system have been found in rats in a number of investigations. ... 

EDB is toxic to the male reproductive system in several species. 

Dalsenter PR, Faqi AS, Webb J, et al Effects of acute exposure to lindane on the male reproductive system I. adult rats. Teratology 51(6) 22A-23A, 1995... 

No toxic effect on male reproductive system, blood chemistry, or growth (5, 15)... 

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