Biochemical effects of some organophosphorus pesticides on the ovaries of albino rats.

An evaluation of the toxic effects of three organophosphates; monocrotophos, dimethoate and methyl parathion on female reproduction was made by biochemical estimations of cytoplasmic and membrance bound proteins, lipids, phospholipids and cholesterol in the rat ovaries after treatment with their low residual level doses (LD50 1/8-1/5) to three groups of six rats each for 90 days. All the three pesticides caused degenerative changes in the ovaries as evidenced by a significant decrease in the concentration of cytoplasmic as well as membrane bound proteins, total lipids, phospholipids and cholesterol. The observations are thus indicative of the reproductive toxicity caused by organophosphates at cellular and molecular level in the ovaries of rats.

Enzymatic changes induced by some organophosphorus pesticides in female rats.

An evaluation of toxic effects of three organophosphorus pesticides viz. monocrotophos, methyl parathion and dimethoate given orally daily for 90 days was done in terms of enzymatic changes in plasma and liver of female albino rats. A significant decrease was observed in the level of esterases in plasma with all the three pesticides. The activity of acid and alkaline phosphatases and aminotransferases increased significantly in plasma and significantly or marginally in liver with these pesticides. The results are thus indicative of the cellular toxicity of these organophosphates even after their subchronic administration in low doses for a long period.

Response related enzymatic changes in ovaries of superovulated mice.

Adult female mice were superovulated with PMSG followed by HCG and 140 blastocysts and 69 morulae were recovered from 24 mice. On the basis of the response, mice were divided into six groups; non responders, 1-5, 6-10, 11-20, 21-30 and >30 embryos. The ovaries of the animals were pooled group wise, homogenized in PBS (pH 7.4) and after centrifugation for 10-15 minutes, the supernatant was analyzed for the enzymes, guanine oxaloacetate transaminase (GOT), guanine pymvate transaminase (GPT), acid phosphatases (ACP) and alkaline phosphatases (AKP). Acid and alkaline phosphatase activities did not show any variation in relation to response to superovulation but GOT and GPT showed significantly increased activity in response to induction of superovulation. A statistically significant positive correlation was found between GOT and GPT activities and the superovulatory response in mice.

Biochemical status of ovaries after induction of superovulation on different days of estrus cycle in mice.

To investigate the role of ovarian status and to find out a suitable hormonal dose for induction of superovulation and its effect on biochemical status of the ovaries, the mice were injected with PMSG in doses of 5, 7.5, and 10 IU on different days of the estrous cycle i.e. proestrus, estrus, metestrus and diestrus followed by hCG injection 48 hr later. All these treatments increased the mean ovarian weight and ovulation rate when compared with that of control animals. Maximum response was observed by treatment with 7.5 IU PMSG on the day of estrus. This treatment resulted in a non-significant decrease in total proteins but a significant increase in the lipid concentrations while no change in cholesterol content of the ovaries of superovulated mice. The activity of acid phosphatase and lactate dehydrogenase significantly increased and alanine aminotranseferase significantly decreased in the ovaries of mice after superovulatory treatment when compared with that of control animals. This reveals that treatment with PMSG and hCG results in metabolic alterations in the ovaries which may perhaps be inducing biosynthetic deficiencies in oocytes as indicated by increased prenatal mortality in superovulated pregnant mice when compared with that of controls in the present studies.

Effects of dietary selenium on biochemical composition of rat testis.

Treatment of rats with selenium (6 and 8 ppm in diet) for 6 and 9 weeks resulted in decrease in testicular protein, phospholipid content and LDH activity and an increase in the lipid, cholesterol content and activity of ACP and ALP. These alterations have been discussed in relation to interference of selenium in various metabolic processes of testis. It seems that selenium affects the oxido-reductase activity of glutathione and resulting in oxidative damage to testis.

Increase in ovarian blood volume during ovulation in adult cyclic rats.

Ovarian blood volume was quantified by measuring optical density (414 nm) of haemoglobin in ovarian extracts and comparing it with that of known amounts of whole blood in the cyclic mature female rats during estrous cycle and periovulatory period. Haemoglobin in ovarian extracts had the same peak absorbance of 414 nm characteristic of oxyhaemoglobin in whole blood taken by cardiac puncture of the rats. There was a linear relationship between the absorbance and volume of whole blood in the sample. The ovarian blood volume was lowest on the day of metestrus and slightly increased on the day of diestrus. On the night of proestrus, the blood volume significantly increased and showed a gradual increase during preovulatory period from 0030 hrs to 0230 hrs and then started decreasing and reached a preovulatory level on the morning of estrus. Ovulation had occurred only in the rats sacrificed after 0230 hrs. Treatment of rats with indomethacin and propranolol significantly reduced the ovarian blood volume observed during the ovulatory period. Epinephrine and norepinephrine did not affect the ovarian blood volume. The results show that the ovarian blood volume changes significantly during the estrous cycle and reaches at maximum level at the time of ovulation which perhaps reflect vasodilatation and hyperemia associated with this process.

Correlation between steroids and plasmin in rat ovaries during ovulatory process.

Progesterone (0.5 mg/rat) and estradiol-17 beta (10 micrograms/rat) injected(im) to adult female albino rats on the morning of proesterous significantly enhanced the ovarian plasmin activity as measured by the fibrin plate method at the time of ovulation which was confirmed to be at 2.30 a.m. by estimation of ovarian plasmin activity at definite intervals before and after ovulation. The ovarian plasmin activity showed a gradual increase towards ovulation and reached a maximum level at 2.30 a.m. and again decreased after ovulation. However, the nonsteroidal estrogen antagonist, tamoxifen induced inhibitory effects on the ovarian plasmin activity as compared to control and estradiol-17 beta treatment. Thus these studies reveal a positive relationship between steroids and the ovarian plasmin activity during ovulation.

Effect of steroids on ovarian neutral proteinases during ovulation in cyclic albino rats.

Progesterone (0.5 mg/rat) and estradiol-17 beta (10 micrograms/rat) injections (im) on the morning of proestrous in cyclic female rats enhanced the ovulation rate (number of ova shed). These steroids also significantly (P less than 0.05) increased the activity of ovarian neutral proteinases, observed on the morning of estrus as compared to those in control and vehicle treated animals. Nonsteroidal estrogen antagonist, tamoxifen suppressed ovulation rate and ovarian neutral proteinase activity as compared to control, its vehicle and steroidal treatment. The results demonstrate a stimulatory effect of progesterone and estradiol 17 beta on ovulation and ovarian neutral proteinases.