Spermicidal agents

In recent years, there is a development of vaginal contraceptives incorporating potent spermicides. Many compounds with different pharmacological activity have been evaluated in vitro for their spermicidal activity. Drugs such as surfaceactive agents (synthetic and natural), ionophores, antiliquefying agents, antimicrobial agents and miscellaneous agents such as gossypol, Azadirachta indica, vanadocenes have all been demonstrated to possess good spermicidal activity. Nonoxynol is the only spermicidal agent currently marketed and widely used. But there is still a need to develop alternative compounds for future use as safe spermicide.

Reduced fertility in female mice exposed transplacentally to diethylstilbestrol (DES)

Prenatal exposure to diethylstilbestrol (DES), a synthetic estrogen, has been associated with a low incidence of vaginal adenocarcinoma as well as a variety of more numerous benign abnormalities in the reproductive tract of human beings and experimental animals. For the purpose of assessing the effects of prenatal exposure to DES on postnatal reproduction tract function, timed pregnant CD-1 mice were treated subcutaneously with doses of DES ranging from 0.01 to 100 microgram/kg/day on days 9 through 16 gestation. The fertility of the female offspring was determined postnatally by a repetitive forced breeding technique. The most striking effect observed was a dose-related decrease in reproductive capacity ranging from minimal subfertility at the lower DES doses to a high frequency of total sterility at the highest DES doses. Reduced reproductive capacity appeared to be a reflection of both a decrease in the total number of litters and smaller litter sizes. A major component of the sterility seen in those females given higher doses of DES was oviductal/ovarian, since the number of ova recovered from the oviductal ampullae after induced ovulation was less than 30% that of controls. In addition, structural abnormalities of the oviduct, uterus, cervix, and vagina were observed, and contributed to infertility. These data suggest that in utero exposure to DES results in permanent impairment of female mouse reproductive capacity. Recent reports of altered pregnancy outcomes in young women who were exposed in utero to DES demonstrate the clinical importance of the findings obtained in mice.

Industrial monosulfhydryl hydrocarbon compounds-a toxicological and pharmacokinetic profile

The relevant published toxicological and pharmacokinetic data on the effects of industrial monosulfhydryl hydrocarbon (MSHC) compounds in humans and animals have been reviewed. These compounds are of occupational and environmental exposure concern to humans because they are manufactured in significant quantities, widely used, and insufficiently studied for long-term exposure effects and epidemiology. Both human and animal exposure studies indicate that the inhalation of low molecular weight (C1-C8) compounds at high concentrations may produce severe central nervous system depression and respiratory paralysis. Short-term inhalation at microgram per liter concentrations does not cause any significant toxicity in humans, but the odors do cause environmental concern. Some delayed toxicity and mortality are seen after subchronic exposure in animals. Respiratory organs are significantly damaged by the inhalation of MSHC compounds, whereas some organ pathology is observed in the spleen, liver, and kidneys after oral and intraperitoneal administration. Dermal toxicity is observed for several high molecular weight compounds (> C8). Of all the compounds tested, monosulfhydrylbenzene is most injurious to the eyes, whereas other compounds cause moderate irritation. Major detoxication products of MSHC compounds are carbon dioxide and urinary inorganic sulfate. Methylation and oxidation are the major pathways for detoxication, with the lungs and kidneys being major organ routes of excretion.

The fate of diethylstilbestrol in the pregnant mouse

There is much current interest in the effect of diethylstilbestrol (DES) on the mammalian fetus; however, little is known concerning the physiologic disposition of DES during pregnancy. Radiolabeled (14C or 3H) DES (30 mug/kg) was given to 16-day pregnant mice and its metabolism, distribution and excretion were studied. After i.v. administration, DES was rapidly cleared from the plasma. The plasma decay rates could be described by the sum of four exponentials having T 1/2 values of 4 seconds, 1.1 minutes, 14 minutes and 13 hours. Moreover, conjugated products of DES accounted for more than one-half of the plasma radioactivity by 5 minutes after dosing. The parent compound was rapidly distributed to blood cells, but the liver was the major site of accumulation of DES and its metabolites. In fact, the total radioactivity in this organ accounted for 50% of the injected dose within 2.5 minutes after treatment. Significant concentrations of radioactivity persisted in liver throughout the 16-hour experiment, with DES conjugates accounting for 80% of the hepatic 14C activity at all time points examined. Approximately 56% of the dose was excreted in the feces within 24 hours, primarily as the parent compound. With DES as substrate, significant levels of UDP-glucuronyltransferase were determined in maternal and fetal liver but not in maternal uterus, placenta of fetal gut. Although the mouse placenta appeared to retard the passage of DES into the fetal compartment, a 3-fold accumulation (relative to fetal plasma) of the compound was found in the fetal reproductive tract.

Alteration by phenobarbital and 3-methyl-cholanthrene of functional and structural changes in rat liver due to carbon tetrachloride inhalation

The effect of carbon tetracholoride (CCl4) inhalation (1100 ppm, 30 minutes) on rat hepatic polyribosomal profile, amino acid incorporation and endoplasmic reticulum were studied in phenobarbital or 3-methylcholanthrene (3-MC) pretreated rats. The inhalation of CCl4 alone caused a partial disruption of the hepatic polyribosomal profile. Rats pretreated with phenobarbital or 3-MC showed complete disruption of the hepatic polyribosomal profile. The hepatic polyribosomal profile returned to normal within 24 hours after exposure to CCl4 in saline and 3-MC-pretreated rats as compared to 48 hours in phenobarbital-pretreated rats. The incorporation of 14-C(U)-L-leucine into 9000 x g liver supernatant fraction protein was decreased in phenobarbital-pretreated rats when measured immediately following or 24 hours after inhalation of CCl4. The incorporation was also decreased in 3-MC-pretreated rats when measured immediately after exposure but not at 6 or 24 hours. The centrolobular hepatocytes of phenobarbital-pretreated rats exposed to CCl4 showed dilation and vesiculation of cisternae of the rough endoplasmic reticulum and striking changes in the nuclear double membrane. Partial recovery occurred within 24 hours and complete recovery within 48 hours after exposure. There were no observable changes in these parameters 0, 6, or 24 hours after exposure to CCl4 in 3-MC-pretreated rats. A new hypothesis is put forward which states that the activation of CCl4 to trichloromethyl free radicals takes place at two sites on the reduced nicotinamide adenine dinucleotide phosphate-cytochrome P-450 electron-transport chain of liver microsomes.