Reproductive system parturition

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. 

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. 

The prostaglandins occur in all tissues but in very small amounts. They act on loci in the same cells as those in which they are synthesized, and their biological roles are diverse e.g., they function in the female reproductive system during ovulation, menstruation, pregnancy, and parturition, and they stimulate uterine muscle contraction. 

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 Effects. Autopsy data have not provided detectable levels of vanadium in human reproductive organs. It is unlikely that the reproductive system is a sensitive indicator for vanadium toxicity in humans. Only one animal study was located that specifically tests the effects of vanadium on reproduction. In this well-conducted rat study, no adverse effects on fertility, reproduction, or parturition were noted when male and female rats were exposed to sodium metavanadate and then mated. 

Effects on the reproductive system. Suffice it to say that PGs cause release of luteinizing hormone, play a part in ovulation, can terminate pregnancy, and initiate parturition. E and F PGs are found in ovaries, fallopian tubes, placenta, menstrual fluid, amniotic fluid (during labor), and in seminal fluid. 

Leptin also has direct effects on a number of other factors influencing animal production. For example, leptin reduces fat deposition in adipose tissue, where it suppresses the expression of acetyl-CoA carboxylase, the rate-limiting enzyme involved in fat synthesis. Leptin also has direct effects on the reproductive system, where it induces the release of follicle-stimulating hormone and lutenising hormone from the anterior pituitary. Its effects on reproduction and embryonic development are broad and include factors such as inducing puberty, especially in thinner animals, and shortening the interval from parturition to oestrus. 

Although the OT system may be regarded as a key regulator of labour, in OT-deficient mice, parturition remains unaffected. Moreover, OTR knockout mice do deliver in a normal fashion, but the offspring die during the very first days of life, due to starving, as the milk ejection reflex is absent in these animals. These experiments show that the OT system is not essential for labour or reproductive behaviour (at least in mice), but for the milk ejection reflex, which is fundamental for litter survival. 

In animals, the lowest LOAEL value was 0.075 mg/kg/day (Bio/dynamics 1991 IRDC 1985). At this dose level, there were significant increases in mortality during late pregnancy and parturition (Bio/dynamic 1991 IRDC 1985), liver necrosis (Bio/dynamics 1991), and neurotoxicity (Bio/dynamics 1991). The IRDC (1985) study also identified aNOAEL of 0.075 mg/kg/day for systemic, developmental, and reproductive effects, and the Bio/dynamics (1991) study identified aNOAEL of 0.075 mg/kg/day for developmental and reproductive effects. At first examination, it appeared that no intermediate oral MRL could be derived because the lowest dose indicated in Table 2-2 was 0.075 mg/kg/day, which was associated with increased... 

Female reproductive toxicity includes adverse effects on reproductive organs and related endocrine systems. Endpoints that reflect toxicity include sexual behavior (receptivity to the male at appropriate times in the cycle), age at onset of puberty, fertility (the ability to produce offspring in normal number), gestation length, parturition, lactation, loss of primordial follicles, and age at reproductive senescence. 

Chlorine (CI2) is one of the more commonly produced chemicals in the United States, and chlorine gas is a potent oxidant that is very irritating and, potentially, corrosive (Wismer, 2007 Kikilo et al., 2008 Smith et al., 2008). Chlorine gas is used as a pulmonary and choking agent, and exposure is frequently associated with moderate to severe painful irritation of the eyes and respiratory tract (Wismer, 2007). Such stressful sublethal exposmes in late-gestational women or animals might be expected to be associated with the induction of premature parturition and, possibly, spontaneous abortion. Oxidative stress can definitely have adverse effects on reproductive function, but the chronic disease usually associated with chlorine gas exposme is primarily related to the ocular and respiratory systems (Smith et al., 2008). The limited information available regarding the reproductive effects of chlorine gas indicates that it is teratogenic (Wismer, 2007). 

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