Female sexual function

The term reproductive toxicity is sometimes used exclusively to describe toxic effects on male and female sexual function and fertility. More commonly, and in this book, reproductive effects are considered to include adverse effects on sexual function and fertility in males and females as well as developmental toxicity. 

Some toxicants are known to affect the female reproductive system and processes. Exposure to the alkylating agents cyclophosphamide and vincristine can lead to loss of female sexual function. Cyclophosphamide may attack and damage the oocytes, cells that lead to egg formation. Pharmaceutical busulfan damages ovaries. The 7,8-diol-9,10-epoxide of benzo(a)pyrene, as well as some other metabolites of polycyclic aromatic hydrocarbons, can be toxic to oocytes. 

Berman, J. R., and Bassuk, J. (2002), Physiology and pathophysiology of female sexual function and dysfunction, World J. Urol., 20,111-118. 

Stimulation of ai-adrenoreceptors will likely lead to detumescense, whereas blockade of these receptors, centrally and peripherally, including penile tissue, may produce erection. Female sexual arousal has been associated with an active sympathetic nervous system, but the overall data concerning the role of various neurotransmitters in female sexual function are still scanty. 

Sexual dysfunction increases in the background population with increasing age. Studies have shown that in men below 40 years of age the prevalence is 1-9%, in 40-59 year olds 20-30% and for the 60-69 year olds 40-50% with a steep increase in the above 70-year olds up to 75%. A number of studies have shown that diabetes significantly increases the risk of sexual dysfunction and generally any person with diabetes has a risk of 35-75% of developing sexual dysfunction. This condition arises earlier in the diabetic person than in the nondiabetic and is most often promoted by the co-existence of late complications of diabetes. There is a very close association to cardiovascular disease and type 2 diabetic patients are therefore at high risk. Sexual problems may even lead to the diagnosis of cardiovascular disease and type 2 diabetes. The above is probably true for women with diabetes as also. In a Swedish survey 47% of women between 18 and 74 years of age had one or several sexual problems and between 60% and 80% were not satisfied with their sex life. There is not much evidence on the impact of diabetes on female sexual function, but it is safe to say that women with diabetes more commonly suffer sexual problems than women without diabetes. 

Goldstein I, Giraldi A, Kodigliu A, van Lunsen RH, Marson L, Nappi RE. Pfaus J, Salonia A, Traish A, Vardi Y. Physiology of female sexual function and pathophysiology of female sexual dysfunction. Lue T F, Basson R, Rosen R, Giuliano F, Khoury S, and Montorsi F. Sexual Medicine. Sexual dysfunctions in... 

Hormonal regulation of female sexual functions and two Images showing a sperm cell fertilizing an egg cell and a human blastocyst five days after conception. 

Female sexual development and behaviour in mammals occurs by default and requires no ovarian secretion, and it is only in genetic males that the testis can secrete hormones which destroy this female pattern and superimpose that of the male. Sexual differentiation is not so well defined in fish, and larval exposure to both synthetic estrogens and androgens is widely used in aquaculture to produce monosex cultures. Endocrine disruption of sexual differentiation in fish may therefore reflect both the complexity and diversity of such processes between different species. Some care is required in use of the terms hermaphrodite and sex-reversal since a true hermaphrodite has both functional testes and ovaries and a sex-reversed fish is fully functional as its final sex—both produce the appropriate viable gametes. Such functional sex-reversal is not possible in mammals, but in some species of fish it is the normal developmental pattern. In most of the cases of hermaphroditism or sex-reversal reported in the non-scientific press, there is evidence only for a few ovarian follicles within a functional testis. This may be considered as feminisation or a form of intersex, and is very clearly endocrine disruption, but it is certainly neither sex-reversal nor hermaphroditism. In some cases the terms have even been used to infer induction of a single female characteristic such as production of yolk-protein by males. 

Abstract Sexual orientation influences human olfactory function. Following a brief review of the biological basis of homosexuality, this chapter explores exactly how olfactory function varies as a result of sexual orientation. Three separate areas of research are considered recent studies on the neural processing of social odorants by heterosexuals and homosexuals the influence of sexual orientation on the production and perception of body odours and the influence of female sexual orientation on menstrual synchrony. 

The function of the flank gland of the golden hamster, Mesocricetus auratus, is not clear but it appears to be involved in signals of sexual and social status and familiarity of the male to the female. Sexually receptive females spend more time near flank scent marks of intact males than castrates, or clean controls. They also stay longer near marks from familiar males than novel males. Finally, these females spend more time near marks of dominant males (compared with subordinate males) (Montgomery-St. Laurent etal, 1988). 

Table 3. Common female-specific end-points of sexual function and fertility ...

Altered sexual function and fertility. Toxicity may be expressed as alterations to the female or male reproductive organs, the related endocrine system or pregnancy outcomes. The manifestations of such toxicity may include, but not be limited to, adverse effects on onset of puberty, gamete production and transport, reproductive cycle normality, sexual behaviour, fertility, gestation, parturition, lactation, pregnancy outcomes, premature reproductive senescence or modifications in other functions that are dependent on the integrity of the reproductive systems. 

What is reproductive toxicity Reproductive toxicity refers to any adverse effect on any aspect of male or female sexual structure, function, and lactation including effects on the reproductive potential and viability of the offspring. This concept may also include the following ... 

In 12 men with schizophrenia (mean age 36 years) receiving neuroleptic drugs, amantadine 100 mg/day for 6 weeks improved sexual function (531). All 12 patients, who had a sustained relationship with a female partner, had reported sexual dysfunction. Four areas of sexual function were assessed desire, erection, ejaculation, and satisfaction there was an improvement in all but ejaculation. Amantadine had no effect on the symptoms of schizophrenia. 

For the purposes of this chapter, the term reproduction will be used primarily in reference to vertebrate species of animals (especially mammals) and will be inclusive of development (Figure 36.1), which is sometimes treated as a separate topic in toxicology texts. This particular chapter emphasizes what is currently known about the adverse effects of known chemical warfare agents and selected environmental contaminants on male and female reproductive function, as well as xenobiotic-induced effects on the growth, maturation, and sexual differentiation of the embryo and fetus. Endocrine disruption is an extremely common mechanism of action for xenobiotics associated with impaired reproductive function and will be discussed along... 

In addition to the effects on the reproductive functions of the female, there has been some study of the effects of tropic acid esters and related compounds on sexual function In che male. One paper on this topic (125) has been mentioned above. Horowitz and Goble (143) have reviewed the literature on drug-induced sexual dysfunction In the male and have concluded chat any drug with acroplne-llke effects may Interfere with penile erection. (They pointed out that Impotence induced by anclmuscarl e drugs may occur without reduction of libido and may thus be particularly frustrating to the male.)... 

The development in subjects receiving the diet alone was slow, and the effect on height increment and onset of sexual function was strikingly enhanced in those receiving zinc. The zinc-supplemented boys gained considerably more height than those receiving ample protein diet alone. The zinc-supplemented subjects showed evidence of early onset of sexual function, as defined by nocturnal emission in males and menarche in females. The two women described in this report were from hospital clinic and represented the first cases of dwarfism in females because of zinc deficiency (20). 

A. Hunter, A Practical Treatise on Disorders of the Sexual Function of the Male and Female, FA Davis, Philadelphia, PA, 1926. 

Reproductive toxicology may be defined as any adverse effect on any aspect of male or female sexual structure or function, including conception and lactation, which may interfere with the production and development of normal offspring to maturity (Witorsch 1995). It is important to recognize the importance of reproductive and teratology studies in the detection of toxicants to the reproductive system (ICH 2005) and perhaps how little used are the biochemical measurements of the hormones that drive the reproductive systems in these regulatory studies. 

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