Sperm maturation

Sperm counts can be performed with sperm from either the testis or the epididymis. Sperm motility is commonly being treated as a measure of sperm viability. The addition of sperm evaluation greatly increases the sensitivity of the study to detect effects on sperm maturation and the current study design will likely detect more male effects than previous designs even though the treatment period has been shortened. 

Radioactivity ( H or "C-1,2-dibromoethane) was detected in spermatozoa collected approximately 1 week following the initial oral dose (Amir 1973). These results indicate that 1,2-dibromoethane exerts spermicidal action during the process of spermiogenesis and sperm maturation. This conclusion was supported by the evidence that the percentage of sperm abnormalities was highest when little 1,2-dibromoethane radioactivity could be detected in sperm. In addition, reduction in sperm concentration was more pronounced in adult bulls than in young bulls, and the period of recovery was longer in adult animals (Amir 1975). In another study, bulls were fed 2 mg/kg/day 1,2-dibromoethane for 12 months followed by 4 mg/kg 1,2-dibromoethane every other day until they reached the age of 14-16 months. The semen samples examined revealed low sperm density, structural abnormalities, and low mobility (Amir and Volcani 1965). Sperm production returned to normal as early as 10 days postexposure (Amir and Lavon 1976 Amir et al. 1977). 

Epididymis histopathology Mating usually imaffected Fertility sperm maturation/function may be affected leading to a decrease in fertility/fecundity... 

Changes in spermatogenesis and sperm maturation have been related to fertility in several test species, but infertility cannot be reliably predicted from these data. This is in part due to the fact that... 

The aim of the study, often called fertility study , is to assess adverse effects of the test compound on maturation of gametes, mating behavior, fertility, preimplantation stages of the embryo and implantation. Adverse effects can be detected at the estrus cycle, tubal transport, implantation, and development of the pre-implantation stages of the embryo. In males, functional effects on libido and epididymal sperm maturation may be detected which cannot be observed by histological examination of the male reproductive organs. 

Hamilton and collaborators have made extensive studies on the complex processes involved in sperm maturation. We noted in Section VIII that, in the course of this work, they found rat rete testis and epididymal... 

In males (Fig. 2. -IO). LH stimulates testosterone synthesis by the testes, and together, testosterone and LH promote spermatogenesis (spenii pnxluction) and development of the testes. Testosterone is also essential for development of secondary sex characteristics in males. FSH stimulates production of proteins and nutrients required for sperm maturation. 

Guiney, P.D., M.J. Melancon, Jr., J.J. Lech and R.E. Peterson. Effects of egg and sperm maturation and spawning on the distribution and elimination of a polychlorinated biphenyl in rainbow trout (Salmo gairdneri). Toxicol. Appl. Pharmacol. 47 261-272, 1979. 

V. PROCESSING OF FERTILIN DURING SPERM MATURATION IN THE TESTIS AND EPIDIDYMIS... 

Hunnicutt, G.R., Koppel, D.E., and Myles, D.G. (1997). Analysis of the process of localization of fertilin to the sperm posterior head plasma membrane domain during sperm maturation in the epididymis. Dev Biol. 797 146-59. 

Extracts of the Chinese vine, Tripterygium wilfordii, have also shown some promise. This male contraceptive affects sperm maturation in the epididymis. Two other drugs work by another mechanism. They prevent the contractions of the muscles that run along the vas deferens, so that seminal fluid and sperm are not pushed along. This results in a dry orgasm with no ejaculation. The drugs are phenoxybenzamine (16.12), which is normally used to control hypertension, and thioridazine (see 16.12), which is an antipsychotic.74 The lack of ejaculation was discovered as a side effect of the normal uses of the drugs. 

No significant differences between exposed and control groups on sperm maturation, total counts, viability, and morphology... 

Clusterin is a heterodimeric glycoprotein produced by a wide array of tissues and found in most biological fluids. The proposed physiologic functions of clusterin include complement regulation, lipid transport, sperm maturation, initiation of apoptosis, endocrine secretion, membrane protection, and promotion of cell interactions. 

The major effect of prolonged therapy is adrenal atrophy. In addition, corticosteroids, which have a similar structure to reproductive steroids (e.g., estrogen and testosterone), can feed back on the production of reproductive steroids. This can result in decreased sperm maturation, in particular, and infertility. 

Sertoli cells to stimulate the production of proteins and nutrients required for sperm maturation, thereby indirectly supporting germ cell maturation. 

Objective evidence of decreased human fertility is therefore difficult to obtain. In contrast to developmental damage, fertility of both men and women can be affected, and in the scientific community it is accepted that the number and quality of sperms is influenced in particular by external (e. g., stress) and internal factors (e. g., psychological variations). Effects on spermatogenesis (sperm maturation) can have various causes, and chemicals can of course activate these effects. In contrast, the ovum is much better protected against external influences. 

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