Arthur W. Rourke

Purified methoxychlor stimulates the reproductive tract in immature female mice

Methoxychlor is an estrogenic pesticide currently used as a substitute for DDT. The estrogenic effects of 98% pure methoxychlor or base-washed pure methoxychlor were examined on reproductive organs of immature mice and compared to control and estradiol-treated mice. Within 24 hours of birth, neonatal mice received 14 daily intraperitoneal injections of one of the following chemicals: sesame oil only, 10.0 micrograms of 17-beta estradiol, or 0.05 mg, 0.5 mg, or 1.0 mg of 98% pure methoxychlor, or 1.0 mg base-washed 98% pure methoxychlor. Equal doses (1.0 mg) of 98% pure or base-washed methoxychlor stimulated the reproductive organs of immature females such that the effects closely resembled those seen after estradiol treatments. In comparison to control mice, these pesticide treatments also induced precocious vaginal opening, persistent vaginal cornification, increased reproductive tract weights, and epithelial hypertrophy in both the vagina and uterus. However, only estradiol treatments significantly elevated albumin levels in the uterine fluid of the immature mice while the highest methoxychlor doses significantly increased the uterine cell heights when compared to all other groups.

Estradiol or methoxychlor stimulates estrogen receptor (ER) expression in uteri.

The estrogenic pesticide methoxychlor (MXC) abnormally alters reproduction in rodents. The influence of MXC on expression of the estrogen receptor (ER) gene was investigated in the uterus of BALB/c mice and compared to the effect of estradiol. Uterine epithelium in control mice is devoid of ER until 5 d of life. Sesame oil, 10.0 micrograms estradiol 17 beta or 1.0 mg of base-washed 95% MXC were injected into neonates (days 1 to 4) and immature mice (days 10 to 14), after which they were sacrificed. By day 5, E or MXC induced production of nuclear ER mRNA and its translation in uterine epithelium. The mRNA was detected by in situ hybridization and ER protein by immunocytolocalization. In controls, ER was present only in stroma and myometrium. By day 15, the nuclei of uterine epithelium, stroma, and myometrium expressed the ER gene, with no apparent influence of E or MXC. Both E and MXC induce premature nuclear expression of the ER gene in neonatal uterine epithelium, without apparent change in ER gene expression between days 10 and 14 of life.

ESTRADIOL AND PESTICIDE METHOXYCHLOR DO NOT EXHIBIT ADDITIVITY OR SYNERGISM IN THE REPRODUCTIVE TRACT OF ADULT OVARIECTOMIZED MICE

The pesticide methoxychlor (MXC) is a DDT substitute that exhibits estrogenic activities in different animals. To determine whether there is synergism between purified MXC and a natural estrogen, ovariectomized adult mice received 3 daily intraperitoneal doses of either 2.5 or 25 ng estradiol-17b or 0.125, 0.25, or 0.5 mg MXC administered separately or in combination. The mice were sacrificed on d 4. Reproductive tracts were excised, weighed, and one uterine horn was flushed with phosphate-buffered saline, with the fluid electrophoresed on a one-dimensional sodium dodecyl sulfate polyacrylamide gel to determine albumin content. The remaining uterine horn and vagina were prepared for histology and epithelial height measurements. Estradiol significantly increased reproductive-tract weights. Although both the vaginal and uterine epithelial heights increased in mice treated with combined chemicals when compared to controls, the organ histology did not show increased stimulation. Albumin content was significantly elevated only in the estradiol group. The present data do not suggest that either synergism or additive effects occurred between an estrogen and MXC in the reproductive tracts of ovariectomized adult mice. In fact, combining MXC with estradiol suggests inhibitory effects.The pesticide methoxychlor (MXC) is a DDT substitute that exhibits estrogenic activities in different animals. To determine whether there is synergism between purified MXC and a natural estrogen, ovariectomized adult mice received 3 daily intraperitoneal doses of either 2.5 or 25 ng estradiol-17beta or 0.125, 0.25, or 0.5 mg MXC administered separately or in combination. The mice were sacrificed on d 4. Reproductive tracts were excised, weighed, and one uterine horn was flushed with phosphate-buffered saline, with the fluid electrophoresed on a one-dimensional sodium dodecyl sulfate polyacrylamide gel to determine albumin content. The remaining uterine horn and vagina were prepared for histology and epithelial height measurements. Estradiol significantly increased reproductive-tract weights. Although both the vaginal and uterine epithelial heights increased in mice treated with combined chemicals when compared to controls, the organ histology did not show increased stimulation. Albumin content was significantly elevated only in the estradiol group. The present data do not suggest that either synergism or additive effects occurred between an estrogen and MXC in the reproductive tracts of ovariectomized adult mice. In fact, combining MXC with estradiol suggests inhibitory effects.

The immune response during proliferative kidney disease in rainbow trout: A case history

Young-of-the-year rainbow trout clinically affected by proliferative kidney disease (PKD), a systemic protozoan infection, exhibit a massive proliferation of small lymphocytes in the posterior kidney and spleen, a decrease in erythrocyte packed cell volume, hemoglobin, and serum albumins and an increase in beta-globulins. Electronphotomicrographs of the causative agent indicate that it is engulfed within a macrophage which is surrounded by small lymphocytes. Fish having survived a clinical episode are completely refractory to subsequent infection. Their serum electrophoretic patterns are quite unremarkable.

Protein secretions in mouse uterus after methoxychlor or estradiol exposure.

Four-month-old, ovariectomized mice were treated with 14 daily ip injections of either 10.0 micrograms of 17 beta-estradiol or 1.0 mg technical grade methoxychlor. Uterine luminal proteins were radiolabeled with 35S-methionine and run on 2-dimensional electrophoresis gels. The influence of methoxychlor or estradiol was compared to untreated controls by examining reproductive tract weights, uterine histology, and the patterns of uterine protein secretions. The data indicate that the stimulation of the uterus in ovariectomized, adult mice by methoxychlor is indistinguishable from that caused by estradiol. Both substances alter reproductive tract weights, promote cellular hypertrophy, stimulate uterine development, and induce the secretion of comparable levels of incorporation of methionine into a large number of proteins. The data further indicate that the alterations in gene expression promoted by estradiol in terms of secreted proteins appear to be qualitatively similar to those caused by the pesticide methoxychlor.

Smoltification in steelhead trout (Salmo gairdneri): Developmental aspects of plasma constituents.

Selected biochemical parameters were measured in the plasma of both underyearling anadromous steelhead trout (Salmo gairdneri) and underyearling residentS. gairdneri. The analyses were conducted in an effort to determine whether or not there might be changes which could be associated with the parr-smolt transformation of anadromous strains. Plasma NH+4 and plasma Na+ were assayed and plasma proteins were analyzed by two-dimensional polyacrylamide gel electrophoresis (2D PAGE).Ammonia was the only plasma ion to show changes with time that were different between the two strains of fish. Proteins prepared by 2D PAGE exhibited developmental changes in both migratory and nonmigratory fish. Each strain exhibited changes with time and the anadromous fish displayed patterns of proteins that were not observed in the nonanadromous strain. It is possible that certain changes in the protein constituents found in anadromous fish are associated with the processes of smoltification. The data are consistent with the notion that this developmental event occurs over an extended period of time and is not restricted to the spring.The data suggest that there may be some changes that occur in certain plasma constituents of migratory fish beginning in the fall and continuing into the spring. The data also indicate that certain ontogenetic events that are not associated with smoltification can be ascertained by analyses of plasma.

The Influences of Addition of Minerals to Rearing Water and Smoltification on Selected Blood Parameters of Juvenile Steelhead Trout, Salmo gairdneri Richardson

Experiments were conducted to determine the influences addition of minerals to rearing water had on selected blood parameters of juvenile steelhead trout, Salmo gairdneri Richardson. Fish that were maintained in water with low mineral concentrations exhibited significant increases in plasma \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage{wasysym} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document}

Changes in Uterine Protein Synthesis during Delayed Implantation in the Western Spotted Skunk and its Regulation by Hormones

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