Reproductive system lactation

Reproductive System. The primary PGs are intimately involved in reproductive physiology (67). PGE2 and PGP2Q, are potent contractors of the pregnant utems and intravenous infusion of either of these compounds to pregnant humans produces a dose-dependent increase in frequency and force of uterine contraction. PGI2 and TXA2 have mild relaxant and stimulatory effects, respectively, on uterine tissue. The primary PGs also play a role in parturition, ovulation, luteolysis, and lactation and have been impHcated in male infertility. 

Hormonal patterns and their regulation are more complex in females than in males due to the female cycle, the fertilization process, gestation and lactation. All functions ofthe female reproductive system are under endocrine control and therefore can be disrupted by effects on the reproductive endocrine system. 

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. 

As indicated above and discussed below, the health effects of DEHP are generally well characterized by the oral route in laboratory animal models. While additional information is always desirable, from a health assessment perspective, there appear to be few overriding needs for additional toxicological information for the principal route of human exposure to DEHP. Of particular importance are additional data that could enable derivation of an acute-duration oral MRL, which is currently precluded by insufficient information on male reproductive system development in offspring acutely exposed during gestation and/or lactation. 

The female reproductive system is also at risk during fetal development in utero, postnatally during puberty, and during her reproductive lifetime until menopause (cessation of ovulation). The traditional end points of concern are ovulation of a normal ovum, fertilization, uterine status, implantation and prenatal development, parturition, and lactation involving nursing (appropriate quality and quantity of milk) and other maternal behaviors. 

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. 

Ejqrert Panel conclusions are summarized in Table 17.4.2. Since primates showed no testis effects when exposed to DEHP at oral doses similar to those which wonld cause testicular toxicity in juvenile rodents, the Expert Panel has a minimal concern that ambient human exposures adversely affect adult httman reproduction However, exposure of healthy infants and toddlers, whose reproductive systems are still developing, is more of concern. Thus, if an infant or toddler is ejqrosed to levels higher than that expected with ambient adult exposiue, the Expert Panel has concern that exposure may adversely affect male reproductive tract development. Because it is possible that exposures of critically ill male infants who are exposed via medical therapy can approach doses that are toxic in rodent models, the Expert Panel has serious concern that such exposure may adversely affect male reproductive tract development. Because oral exposure for humans is estimated at <30 tg/kg bw/day and toxic effects are observed in rodents at >3 mg/kg bw/day, the Expert Panel has concern that ambient oral DEHP exposures of pregnant or lactating women may adversely affect the development of their offspring. 

There are receptors in many parts of the brain, as well as elsewhere in the body, such as the reproductive system. In lactating mothers who are... 

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