Effect of lindane on eggshell characteristics and calcium level in the domestic duck

Environmental exposure to non-steroidal anti-inflammatory drugs and potential contribution to eggshell thinning in birds

Abnormally thin eggshells can reduce avian reproductive success, and have caused rapid population declines. The best known examples of this phenomenon are the widespread population crashes in birds, mostly raptors, fish eating birds, and scavengers, caused by the pesticide DDT and its isomers in the 1960s. A variety of other chemicals have been reported to cause eggshell thinning. Non-steroidal anti-inflammatory drugs (NSAIDs), which are extensively and increasingly used in human and veterinary medicine, may be one particularly concerning group of chemicals that demonstrate an ability to impair eggshell development, based both on laboratory studies and on their known mechanism of action. In this review, we outline environmental and wildlife exposure to NSAIDs, describe the process of eggshell formation, and discuss pathways affected by NSAIDs. We list pharmaceuticals, including NSAIDs, and other compounds demonstrated to reduce eggshell thickness, and highlight their main mechanisms of action. Dosing studies empirically demonstrated that NSAIDs reduce eggshell thickness through cyclooxygenase inhibition, which suppresses prostaglandin synthesis and reduces the calcium available for the mineralization of eggshell. Using the US EPA's CompTox Chemicals Dashboard, we show that NSAIDs are predicted to strongly inhibit cyclooxygenases. NSAIDs have been observed both in the putative diet of scavenging birds, and we report examples of NSAIDs detected in eggs or tissues of wild and captive Old World vultures. We suggest that NSAIDs in the environment represent a hazard that could impair reproduction in wild birds.

Guppy sexual behavior as an effect biomarker of estrogen mimics

There is widespread concern that some environmental chemicals can reduce the reproductive capability of humans and wildlife by mimicking natural estrogens and disrupting endocrine function. This potential threat to animal populations posed by xenoestrogens has, hardly surprisingly, been met by an intensive global effort to identify and develop biomarkers suitable for screening chemicals for estrogen mimicking capacity. Despite this effort, there are few biomarkers capable of linking exposure to xenoestrogens to impaired reproductive capability. The reproductive success of most animals depends strongly on the ability to perform the appropriate sexual behavior. The sexual display of the male guppy is strongly linked to reproductive success and is readily quantified under laboratory conditions. This preliminary study demonstrates that exposure of adult male guppies to water weakly contaminated with either natural estrogen (17beta-estradiol) or the xenoestrogen (4-tert-octylphenol) causes a dramatic decrease in the rate and intensity of sexual display. It is concluded that quantitative analysis of the sexual display of male guppies holds great promise as a biomarker at the organismal level for the effects of estrogen mimicking xenobiotics.

DDE-induced eggshell thinning in birds: effects of p,p'-DDE on the calcium and prostaglandin metabolism of the eggshell gland

1. The focus of this review is the effects and mechanism of action of p,p'-DDE on eggshell formation in birds. Inhibition of prostaglandin synthesis in the eggshell gland mucosa is a probable mechanism for p,p'-DDE-induced eggshell thinning. 2. The duck is sensitive to p,p'-DDE-induced eggshell thinning but the domestic fowl is not, and studies comparing the two species in regard to the calcium and prostaglandin metabolism of the eggshell gland have shown that eggshell thinning induced by p,p'-DDE in ducks is accompanied by reduced activity of prostaglandin synthetase, reduced levels of prostaglandin E2, and reduced uptake of 45Ca by the eggshell gland mucosa. The content of calcium, bicarbonate, chloride, sodium, and potassium are also reduced in the eggshell gland lumen in ducks exhibiting eggshell thinning. None of these effects are seen in the domestic fowl. 3. Inhibition of prostaglandin synthesis is a specific effect of p,p'-DDE. The detrimental effects of p,p'-DDE on the eggshell gland seem to be unique when comparing the compound with structurally related substances, i.e., similar treatment regimens with o,p'-DDE, p,p'-DDT, o,p'-DDT, and p,p'-DDD do not cause eggshell thinning in ducks. Neither do they inhibit prostaglandin synthesis in the eggshell gland mucosa. 4. Administration of other compounds that do inhibit prostaglandin synthesis, e.g., indomethacin, does cause the same effects as those seen with p,p'-DDE, i.e., eggshell thinning and the described effects on the calcium and prostaglandin metabolism of the eggshell gland.

The effects of lindane and linuron on calcium metabolism, bone morphometry and the kidney in rats

Experiments were performed to investigate the effects of lindane and linuron on calcium metabolism, femur morphometry and nephrotoxicity. Long-Evans hooded rats were dosed daily for 10 weeks with 0, 10 or 20 mg lindane or 10, 20 or 40 mg linuron/kg body weight beginning at weaning. Lindane significantly decreased urinary calcium concentration, serum alkaline phosphatase concentration and the cross-sectional medullary area of the bone. Lindane was nephrotoxic at both dose levels as demonstrated by elevated kidney weights, kidney-to-body-weight ratios, urinary LDH, tubule regeneration and hyaline droplet degeneration. Linuron significantly reduced medullary cross-sectional area at the 2 higher dose levels and decreased the total femur cross-sectional area at the highest dose level in the absence of effects on calcium excretion. Femur density and strength were also significantly reduced at the highest dose level of linuron. Neither compound affected the serum concentrations of parathyroid hormone or 1,25-dihydroxy Vitamin D-3. Both linuron and lindane exposure significantly increased serum cholesterol concentrations and reduced serum triglyceride concentrations. Both compounds affected calcium metabolism and/or bone morphometry but possibly by different mechanisms since the effects were not the same.

Lindane (gamma-HCH) causes reproductive failure and fetotoxicity in mice

Lindane (gamma-Hexachlorocyclohexane) was orally given to pregnant Swiss female mice at various stages of pregnancy. During early pregnancy (1-4 days of gestation), the insecticide caused total absence of any implantation site, while given during mid pregnancy (6-12 days of gestation), lindane caused total resorption of fetuses. Lindane administration during late pregnancy (14-19 days of gestation) resulted in death of all pups either within 12 h (high-dosed group) or 5 days (low-dosed group) of parturition. Body weight of such pups were also highly reduced. When estrogen was given together with lindane at early pregnancy, implantation was normal, although subsequent fetal development was adversely affected. Progesterone, unlike estrogen, could not correct lindane-induced failure in implantation. On the other hand, when estrogen and progesterone were simultaneously given to lindane-fed mice during early pregnancy, both implantation and subsequent fetal development became comparable to normal mice. The insecticide besides being fetotoxic, thus appears to cause steroid hormone deficiency resulting in reproductive and developmental failure.

Effect of lindane on hormonal control of reproductive function in the female rat

The effect of the gamma isomer of 1,2,3,4,5,6-hexachlorocyclohexane, lindane, on reproductive function in the female rat was examined in two experiments. In the first experiment, chronic treatment with 0, 5, 10, 20, and 40 mg/kg lindane delayed vaginal opening and disrupted ovarian cyclicity until approximately 110 days of age. Thereafter, regular ovarian cycles were present in the majority of females in all dose groups. When killed on the day of vaginal proestrus, the females receiving the two higher doses of lindane had smaller pituitary and uterine weights, lower serum and pituitary luteinizing hormone (LH) and prolactin, and higher pituitary follicle stimulating hormone (FSH) concentrations than the oil-treated control females. Serum estrogen concentrations were not different from controls in the 5 and 20 mg/kg groups, significantly greater than the controls in the 10 mg/kg group, and significantly less than the controls in the group receiving 40 mg/kg. In a second experiment, the uterine weight and pituitary hormone response of 28-day-old, lindane-treated females to a 10-micrograms injection of estradiol benzoate (EB) were investigated. The uteri of the lindane-treated prepubertal females were smaller than controls at 30 hr after EB injection. Furthermore, the EB-induced increase in serum luteinizing hormone, observed at 30 hr after EB injection, was lower in the lindane-treated animals. Similarly, the reduction in pituitary LH, FSH, and prolactin induced by EB was not as great in the lindane-treated animals as in the controls. Serum estrogen concentrations in the lindane-treated animals were not different from controls. These data indicate that lindane may effectively block the response of estrogen-dependent tissues to this ovarian steroid hormone and that this apparent antiestrogenic effect of lindane is responsible for the disturbances observed in the neuroendocrine control of ovarian function in the rat.

Possible antiestrogenic activity of lindane in female rats

During chronic peroral (PO) treatment of weanling, female Fischer 344 rats with daily injections (0.069 mmol/kg) of either 1,1'-(2,2,2-trichloroethylidene) bis [4-chlorobenzene] (p,p'-DDT), 2,4-dichlorophenoxy acetic acid (2,4-D), or gamma-hexachlorocyclohexane (lindane), the lindane treatment induced a significant 20% increase in body weight after 110 days. Further investigation with 0, 5, 10, 20, and 40 mg/kg lindane confirmed a significant increase in average body weight gain at the two highest doses after ten weeks of treatment. Significantly greater food consumption was observed, and the Lee index indicated that lindane treatment induced obesity. In addition to obesity, lindane caused a delay in vaginal opening, disrupted estrous cycling, reduced pituitary and uterine weight, and elevated food consumption during proestrus (when appetite is normally suppressed by estradiol). These responses suggest that, by inducing alterations in the reproductive function of the female rat and by interfering with hormonal regulation of energy balance, lindane may be antiestrogenic rather than estrogenic as previously proposed.