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Biomedical subjects

N M Biswas

Publications and source records attributed to N M Biswas.

At least 37 records · Page 2Linked to original sources
PubMed1990

Effect of dihydrotestosterone on serum concentrations of alpha 2u-globulin and on spermatogenesis in melatonin-treated rats.

Adult male rats were given s.c. injections of melatonin (400 micrograms/100 g body weight per day) for 14 days. On day 15, the weights of the testis and accessory sex organs were less, testicular 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activity was inhibited, spermatogenesis was suppressed and serum levels of gonadotrophins, testosterone and alpha 2u-globulin were decreased compared with control animals injected with vehicle. In a third group of rats given the same dose of melatonin for 14 days, administration of dihydrotestosterone (DHT) at a dose of 25 micrograms/100 g body weight per day on days 8-14 resulted in serum levels of alpha 2u-globulin, FSH, LH and testosterone and testicular 17 beta-HSD activity similar to those seen in vehicle-injected control animals. Weights of the testes and accessory sex organs and spermatogenesis were normal after administration of DHT in melatonin-treated rats. In another group of rats, the depressive effects of melatonin treatment on plasma gonadotrophins were reversed by the administration of alpha 2u-globulin on days 8-14. It was concluded that treatment with DHT prevents the depressive action of melatonin on testicular function by inducing the synthesis of alpha 2u-globulin.

17-Hydroxysteroid Dehydrogenases↗
PubMed1990

Effect of lithium chloride on adrenocortical activity in male rats: evidence of dose and duration dependent response.

Changes in the adrenal weight, adrenal 5-ene-3 beta-hydroxysteroid dehydrogenase (5-ene-3 beta-HSD) activity and serum levels of corticosterone were observed in male wistar rats after the treatment of lithium chloride in the doses of 100, 200 and 400 micrograms/100 g of body weight/day for 7, 14 and 21 days. The experiments indicate that 200 and 400 micrograms/100 g.b.w. administered for 14 and 21 days caused a significant stimulation in the activities of adrenal 5-ene-3 beta-HSD along with elevation of adrenal weights and serum levels of corticosterone. 100 micrograms of lithium chloride was not able to modulate the adrenal activity. Moreover, plasma levels of lithium remain in therapeutic range in this experiment at the doses of 200 and 400 micrograms/100 g body weight. Therefore, our data suggest that lithium can alter the adrenal activity within its therapeutic range according to the duration of treatment.

3-Hydroxysteroid Dehydrogenases↗
PubMed1990

Direct effects of lithium chloride on testicular delta 5-3 beta and 17 beta-hydroxysteroid dehydrogenase activities in the rat--in vitro study.

Testicular delta 5-3 beta- and 17 beta-hydroxysteroid dehydrogenase (delta 5-3 beta- and 17 beta-HSD) activities of rat are inhibited in vitro by a wide range of lithium concentration. The inhibitory effects of lithium are evident at a concentration of 2.5 mM which is easily achieved during the treatment of acute manic patients with lithium. This suggests that lithium exerts a direct inhibitory effect on testicular hydroxysteroid dehydrogenase activities.

17-Hydroxysteroid Dehydrogenases↗
PubMed1990

Effect of testosterone on adrenal corticosteroidogenesis in lithium treated male rats.

Lithium chloride at a dose of 200 micrograms/100 g body weight/day given for 21 days caused a significant increase in adrenal weight, adrenal 5-ene-3 beta-hydroxysteroid dehydrogenase (5-ene-3 beta-HSD) activity along with elevation in serum level of corticosterone on the 22nd day in the rat. Administration of testosterone for the last 14 days to lithium treated rats caused a significant decrease in adrenal weight, adrenal 5-ene-3 beta-HSD activity and serum level of corticosterone in comparison to lithium treated animals.

3-Hydroxysteroid Dehydrogenases↗
PubMed1990

Acid and alkaline phosphatase activities in lithium treated testis, prostate and seminal vesicles of adult albino rats: evidence of duration and dose dependent response.

Changes in the activities of acid and alkaline phosphatase were observed in the testis, prostate and seminal vesicle after the injection of lithium chloride at the doses of 100, 200 and 400 micrograms/100 g body weight/day for 7, 14 and 21 days. The studies indicate that 200 and 400 micrograms/100 g body weight for 14 days and 21 days showed a significant inhibition in the activity of acid phosphatase in all the above reproductive organs. There is a significant stimulation of alkaline phosphatase activity at the doses of 200 and 400 micrograms of lithium after 21 days of treatment in testis, prostate and seminal vesicle along with significant decrease in accessory sex organs weight in comparison to control animal. Therefore, it is evident that the effect of lithium on male reproductive organs mainly depends on the amount of the drug being injected and the duration of treatment to it.

Acid Phosphatase↗
PubMed1990

Effect of lithium chloride on spermatogenesis and testicular delta 5-3 beta, 17 beta-hydroxysteroid dehydrogenase activities in the 'antiserum to luteinizing hormone' treated toad (Bufo melanostictus).

Activities of delta 5-3 beta- and 17 beta-hydroxysteroid dehydrogenase (delta 5-3 beta-HSD and 17 beta-HSD), Leydig cell nuclear area (LCNA) and spermatogenesis in the testis were observed after injection of lithium chloride in the 'antiserum to luteinizing hormone (LH)' treated toad. A significant decrease in the activities of steroidogenic enzymes, LCNA and spermatogenesis were noticed after the injections of 'antiserum to LH' to toads. Further decrease in the activities of the above parameters was observed in the lithium chloride--'antiserum to LH' treated toad. It is suggested that lithium chloride may inhibits testicular function without modulating the pituitary activity.

17-Hydroxysteroid Dehydrogenases↗
PubMed1990

Influence of pituitary on histology of Bidder's organ in castrated toad Bufo melanostictus.

Weight, number of follicles and corpora lutea of Bidder's organ increased significantly after castration of adult toad in breeding season. Removal of pituitary along with testes decreased both weight and number of follicles and corpora lutea. Administration of luteinizing hormone (LH) in castrated and hypophysectomized toad showed more or less similar result as that of control indicating that LH has an effect on the histology of Bidder's organ in the toad.

Animals↗
PubMed1988

The role of alpha-2u-globulin in corticosteroidogenesis in male rats.

Administration of estradiol-17 beta for 7 days to the adult male rat results in adrenal hyperplasia, decreased serum corticosterone along with elevation in serum ACTH and inhibition of adrenal 5-ene-3 beta-hydroxysteroid dehydrogenase activity (5-ene-3 beta-HSD). Treatment with alpha 2u-globulin for following 14 days of estrogen-treated rats reversed the effects of estrogen while in normal rats alpha 2u-globulin treatment increased adrenal 5-ene-3 beta-HSD activity and serum corticosterone level while causing a fall in serum ACTH. It is concluded that alpha 2u-globulin may play a role in ACTH secretion by inducing corticosterone synthesis.

3-Hydroxysteroid Dehydrogenases↗
PubMed1985

Brain 5-hydroxytryptamine and plasma testosterone in L-tryptophan treated rats.

Loading of L-tryptophan for 7 and 21 days increased brain 5-hydroxytryptamine (5-HT) level which was associated with decreased plasma testosterone level. Human chorionic gonadotropin (HCG) administration in L-tryptophan treated rats for 21 days increased the plasma testosterone level in spite of increased brain 5-HT level. These results suggest that brain 5-HT exerts an inhibitory influence on testicular steroidogenesis by modulating the gonadotropin-releasing-factor (GnRH) release and thence pituitary gonadotropins.

Animals↗
PubMed1985

Effect of intraventricular injection of 5,6-dihydroxytryptamine on spermatogenesis and plasma testosterone levels in the rat.

Quantitative evaluation of spermatogenesis at stage VII of the cycle of the seminiferous epithelium and radioimmunoassay of plasma testosterone were performed in adult Wistar rats after intraventricular injection of 5,6-dihydroxytryptamine (5,6-DHT). The rats were killed 2, 10 and 21 days after injection. Brain 5-hydroxytryptamine (5-HT) and plasma testosterone levels were found to be significantly lower in all rats treated with 5,6-DHT. A significant reduction in step 7 spermatid count was also observed after 10 and 21 days. Supplementation with human chorionic gonadotrophin for 21 days in rats injected with 5,6-DHT partially prevented the step 7 spermatid degeneration and increased testosterone levels without producing any effect on brain concentrations of 5-HT. These results suggest that changes in testicular steroidogenesis and spermatogenesis are secondary to pituitary gonadotrophin release which, in turn, is under the influence of brain 5-HT neurones.

5,6-Dihydroxytryptamine↗
PubMed1984

Influence of pineal gland on spermatogenesis of toad (Bufo melanostictus).

The relationship between the pineal gland and testes of the toad was investigated in breeding and hibernating seasons. Pinealectomy increased spermatogenesis in hibernating toads but it failed to exert any effect during the breeding season. The pineals were found to be active during hibernation and atrophied in the breeding season. It is speculated that the cyclic pineal activity might be responsible for the seasonal variation of spermatogenesis in the toad.

Animals↗
PubMed1983

Effect of corticosterone on adrenal 5-ene-3 beta-hydroxysteroid dehydrogenase in estrogen-treated rats.

Treatment of adult male rats with estradiol-17 beta for 7 days results in adrenal hyperplasia, increased level of serum ACTH along with reduction in serum level of alpha 2u-globulin and inhibition of adrenal 5-ene-3 beta-hydroxysteroid dehydrogenase (5-ene-3 beta-HSD) activity. Administration of corticosterone in estrogen-treated rats reverses the effects of estrogen while in normal rats corticosterone treatment reduces adrenal weight, serum ACTH and adrenal 5-ene-3 beta-HSD activity. In vitro experiments show that alpha 2u-globulin fails to change adrenal 5-ene-3 beta-HSD activity in corticosterone pretreated rats while in normal and estrogen pretreated rats alpha 2u-globulin increases 5-ene-3 beta-HSD activity.

3-Hydroxysteroid Dehydrogenases↗
PubMed1983

Effect of alpha 2u-globulin on serum concentration of gonadotrophins and testicular activity in oestrogen-treated rats.

Adult male rats were given injections of oestradiol-17 beta (50 micrograms/100 g body wt per day) for 7 days. When they were killed 14 days after the last injection, serum levels of gonadotrophins and testosterone and weights of accessory sex organs were less, testicular 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activity was suppressed and spermatogenesis was inhibited. Administration of alpha 2u-globulin (1.5 mg/day) for 14 days to oestrogen-treated rats and for 10 days to control rats resulted in increased concentrations of gonadotrophins and testosterone in the serum. Accessory sex organ weight and spermatogenesis appeared to be normal while 17 beta-HSD activity increased in oestrogen-treated rats after treatment with alpha 2u-globulin. It was concluded that alpha 2u-globulin has an effect on testicular function in oestrogenized rats by inducing gonadotrophin and testosterone synthesis.

17-Hydroxysteroid Dehydrogenases↗