Walter Krause

Alterations of the seminiferous epithelium and the leydig cells of the rat testis after the application of dichlorvos (DDVP)

Publications on fertility disturbances caused by insecticides first dealt with chlorinated hydrocarbons, e.g. DDT or Lindane (1,3). Due to their cumulation in the organism they are more likely to cause disturbances in all organs than alkylphosphates, which can be reduced more quickly. Dimethyl-2-dichlorvinylphosphate (DDVP), which is examined in this study, is quickly reduced by hydrolysis in the organism or excreted unchanged(2). JONES (1972) proved by experiments with radioactively marked substance that 80% of the DDVP intake disappears from the body within 6 hours after application. Yet the LD 50 for rats and men is about 80-100 mg/kg (13). The influence on fertility was not discussed. LOFROTHs (1970) in vitro reports, i.e. that DDVP triggers chromosomes breaks, caused us to examine the effects on spermiogenesis.

Influence of DDT, DDVP and malathion on FSH, LH and testosterone serum levels and testosterone concentration in testis.

SummaryGroups of adult male rats were treated with DDT, DDVP or malathion orally for two or three weeks. Body weight and testis weight did not change. FSH and LH levels in serum also remained unchanged, whereas that of testosterone was decreased by DDT. This substance also diminished the concentration of testosterone in the testis. Therefore, the previously observed damage to spermatogenesis by DDT are assumed to be caused by a lack of androgens. Those following treatment with DDVP or malathion seem to be due to a direct cytotoxic effect.

Damage to spermatogenesis in juvenile rat treated with DDVP and malathion

SummaryJuvenile male rats received either 20 mg DDVP or 40 mg malathion/kg on the 4th and 5th day of life, and either 10 mg DDVP or 20 mg/kg malathion daily from the 4th to the 23rd day of life. The histological examination of the testes showed slight reductions of the spermatogenetic cells and Leydig cells. Therefore, it is assumed that testosterone synthesis is reduced, followed by damage to spermatogenetic cells. All disturbances return to normal by the 50th day of life.

The effect of DDT on spermatogenesis of the juvenile rat

SummaryJuvenile male rats of Wistar/Han strain were fed DDT suspended in olive oil. They received either 500 mg/kg at the 4th and 5th or 200 mg/kg daily at the 4th till 23rd day of life. After certain intervals the testes were examined histologically, and at the 60th and 90th day of life fertility was proved. The spermatogenetic cells showed an increase of the physiological degeneration in the course of spermatogenesis and a decrease of their total number. The number of Leydig cells was diminished. In parallel, the litters of normal female rats mated to treated males were smaller than those of controls. The hypothesis is suggested that the damage of the seminiferous epithelium can be explained by a lack of local testosterone.

Fibrinogenolysis by insolubilized plasmin

Abstract Insolubilized plasmin was prepared by chemical fixation of the enzyme to CNBr-activated agarose. The enzyme is still active, whereas its specific activity is reduced. Fibrinogenolysis by insolubilized plasmin is compared to fibrinogenolysis by the soluble form of the enzyme.