Shamim Haider

Germinal vesicle breakdown in oocytes of catfish, Mystus vittatus (Bloch): Relative in vitro effectiveness of estradiol-17β, androgens, corticosteroids, progesterone, and other pregnene derivatives

The relative in vitro effectiveness of estradiol-17 beta, androgen, corticosteroids, progesterone, and other pregnene derivatives on germinal vesicle breakdown (GVBD) using folliculated oocytes of an Indian catfish Mystus vittatus was investigated. 17 alpha,20 beta-Dihydroxyprogesterone was found to be the most effective maturation-inducing steroid (MIS). Estradiol-17 beta and testosterone were not effective but androsterone was found to be fairly effective in final oocyte maturation. Deoxycorticosterone (DOC), hydrocortisone, progesterone, and 17 alpha-hydroxyprogesterone were also effective at their higher concentrations. Among 5 beta-reduced pregnenes, all but 5 beta-pregnene-3 alpha-ol-20-one could induce oocyte maturation. The significance of these findings in relation to the progestagens as natural MIS and the present controversial position of another Indian catfish Heteropneustes fossilis is discussed in the light of available literature.

Oocyte maturation inClarias batrachus. III. Purification and characterization of maturation-inducing steroid.

Maturation-inducing steroid (MIS) in the Indian female catfish,Clarias batrachus, was purified and characterized from the incubation medium in which fully grown but immature folliculated oocytes were incubated with salmon gonadotropin (SG-G100) for 36 h. Maturation-inducing (MI) activity of residues obtained at various steps of extraction and purification was assessed byin vitro germinal vesicle breakdown (GVBD) assay using folliculated oocytes ofC. batrachus. The post incubation medium was extracted with diethyl ether. The ether phase was partitioned using 50% methanol plus n-hexane. The methanol phase which had MI activity was fractionated into 7 fractions using reverse-phase high-performance liquid chromatography. Of these 7 fractions, fraction 3 was found to be active in having MI ability and identified as 17 α,20β-dihydroxy-4-pregnen-3-one (17α,20β-diOHprog). The authenticity of 17α,20β-diOHprog as the major follicular mediator of gonadotropin-induced oocyte maturation was further confirmed by thin-layer chromatography (TLC) in which fraction 3 was run along with authentic 17α,20β-diOHprog standard. This investigation gives a direct evidence that 17α,20β-diOHprog is the major naturally occurring MIS in Indian female catfish,C. batrachus.

Effect of malathion and endosulfan on brain acetylcholinesterase and ovarian steroidogenesis ofChanna punctatus (bloch)

The effect of sublethal concentrations of malathion (organophosphorus insecticide) and endosulfan (organochlorine insecticide) was investigated in Channa punctatus. Brain acetylcholinesterase (AchE) and ovarian delta 5,3 beta-hydroxysteroid dehydrogenase (delta 5,3 beta-HSD) and glucose-6-phosphate dehydrogenase (G-6-PD) activities were studied. Apart from the loss of stage II and III oocytes, the absence of delta 5,3 beta-HSD and G-6-PD activity indicating the inhibition of steroidogenesis was seen in the malathion- and endosulfan-treated fish ovaries. Malathion demonstrated a dose-dependent inhibition of brain AchE activity, whereas endosulfan caused no significant reduction of AchE activity.

Epididymis of the Indian wall lizard (Hemidactylus flaviviridis) during the sexual cycle and in response to mammalian pituitary gonadotropins and testosterone

The histology and histochemistry of the epididymis of the Indian wall lizard Hemidactylus flaviviridis (Rüppell) was studied in normal and hormone‐treated males. The ductus epididymidis showed a considerable variation in epithelial cell height and lumenal diameter along its length. It can be divided approximately into anterior, middle, and posterior regions. Epithelial cell height was maximal in the middle region and minimal in the posterior region. The lumen of the ductus epididymidis increased markedly in diameter from anterior to posterior ends with a concomitant increase in the sperm density. During the breeding phase, epithelial cell height and lumenal diameter of both ductuli and ductus epididymidis become markedly enlarged. The epithelium of reproductively active ducts was filled with secretory granules. Both the secretory granules of the epithelium and the secretory material mixed with sperm in the lumen showed a positive reaction to Sudan Black‐B, indicating the presence of lipid. The relative effects of mammalian FSH and LH on the regressed epididymis revealed that only FSH was capable of stimulating the growth and secretory activity of the epididymis.

Effect of commercial formulation of four organophosphorus insecticides on the Ovaries of a freshwater teleost, Mystus vittatus (bloch): a histological and histochemical study

The chronic effect of an exposure to a sublethal concentration of commercial formulation of 4 organophosphorus insecticides such as birlane (chlorfenvinphos), gardona (tetrachlorvinphos), phosdrin (mevinphos) and malathion on midvitellogenic ovaries of Mystus vittatus was investigated using several histological and histochemical techniques. The loss of stage II and III oocytes accompanied by a significant decline in gonadosomatic index was recorded. The vitellogenesis in treated fishes was ceased as the oocytes did not advance to further stages as evidenced by the absence of lipid yolks and the lack of a PAS positive follicular layer. The RNA content of remaining stage I oocytes of exposed fishes resembled that of the stage I oocytes of the control fishes. The absence of delta 5-3 beta-hydroxysteroid dehydrogenase suggested the lack of steroidogenesis. Reduced glucose-6-phosphate dehydrogenase activity was also observed. The significance of these observations has been discussed in light of available literature.

Effects of cyproterone acetate and flutamide on the testis and epididymis of the Indian wall lizard, Hemidactylus flaviviridis (Ruppell).

Intramuscular injections of 0.2 mg cyproterone acetate (CA) or flutamide every other day for 6 weeks resulted in the inhibition of spermatogenesis. While CA treatment reduced the weight of the testis significantly, flutamide did not. Inhibition of steroidogenesis, indicated by an accumulation of sudanophilic lipid and a decrease in delta 5-3 beta-hydroxysteroid dehydrogenase and glucose-6-phosphate dehydrogenase activity, was evident in the Leydig cells of CA-treated testis. Flutamide, on the other hand, had no effect on the activity of Leydig cells. A marked decline in epididymal weight, as well as reduction in epithelial cell height, was caused by both CA and flutamide. The epithelial cells of epididymes of treated lizards exhibited an accumulation of sudanophilic lipid material in their cytoplasm. However, sudanophilic secretions present in the lumina of epididymal tubules were greatly reduced. This indicates either lack of synthesis of lipid or decrease in its turn over. Our results are in agreement with those obtained in mammalian species after CA or flutamide treatment where a decrease in fertility is suggested.

Tetrapodlike features of the hypothalamohypophysial vascularization in the air-breathing teleost, Heteropneustes fossilis (Bl.).

Abstract In Heteropneustes fossilis the midventral floor of the hypothalamus is the site of the formation of median neurosecretory tracts and the uniting place of the median and the main tracts. Hence this area has a close network of neurosecretory axons, and at least some of them seem to terminate in this region. It is also the site of formation of the capillary plexus, which is in close contact with the neurosecretory axons. Thus, it is comparable to the median eminence of the tetrapods. Blood from the primary capillary plexus is conducted into the pituitary by portal vessels, which largely irrigate both pars distalis and pars intermedia. Some of them, along with the direct branches of the median hypophysial arteries, contribute to the formation of the interface vascular plexus lying in between the rostral neurohypophysis and pars distalis. From the interface vascular plexus also, blood vessels penetrate into the glandular pituitary. Thus the rostral neurohypophysis also functions as a median eminence.

Relativein vitro effectiveness of estradiol-17β, androgens, corticosteroids, progesterone and other pregnene derivatives on germinal vesicle breakdown in oocytes of Indian major carps,Labeo rohita, Cirrhinus mrigala andCatla catla

The relative effectiveness of estradiol-17β, androgens, corticosteroids, progesterone and other pregnene derivatives on germinal vesicle breakdown (GVBD) was investigatedin vitro using folliculated oocytes of three carps,Labeo rohita, Cirrhinus mrigala, andCatla catla. In all three species progesterone and 17α-hydroxyprogesterone could induce GVBD but relatively 17α,20β-dihydroxyprogesterone was consistently found to be the most potent maturation-inducing steroid. Both estradiol-17β and testosterone were ineffective in inducing GVBD. Androsterone and dehydroepiandrosterone were found to be effective inC. catla at all the concentrations used. Deoxycorticosterone (DOC), hydrocortisone (HC) and cortisone were effective inducer of GVBD inC. catla whereas inL. rohita andC. mrigala only cortisone was found to be effective. All 5β-reduced pregnenes were effective in inducing GVBD inL. rohita but inC. catla, only 5β-pregnane-17α-01-3,20-dione and 5β-pregnane-3α,17α,20β-triol and inC. mrigala, 5β-pregnane-3α-ol-20- one could induce oocyte maturation.

In vitro effect of malathion and endosulfan on the LH-induced oocyte maturation in the common CARP, Cyprinus carpio (L.)

Effect of malathion (organophosphorus insecticide) and endosulfan (organochlorine insecticide) on in vitro LH-induced oocyte maturation was investigated in the oocytes of common carp, Cyprinus carpio. In control incubation, LH at the concentration of 10 μg mL−1 induced 41.2 ± 1.6% of germinal vesicle breakdown (GVBD). When the oocytes were incubated with malathion at the concentrations of 1000, 500, 100, and 50 ppb together with LH it could induce only 13.4 ± 0.4, 14.0 ± 1.0, 12.9 ± 3.5, and 18.1 ± 3.9% of GVBD, respectively. Similarly, when the oocytes were incubated with endosulfan at the concentrations of 0.5, 0.1, 0.05, and 0.01 ppb together with LH, it induced only 12.8 ± 1.6, 8.8 ± 1.2, 20.9 ± 2.1 and 26.0 ± 2.2% of GVBD, respectively. The significance of the result obtained were discussed on the basis of available literature.

Effect of commercial formulation of four organophosphorus insecticides on the LH-induced germinal vesicle breakdown in the oocytes of a freshwater teleost, Mystus vittatus (bloch)—A preliminary in vitro study

Effect of commercial formulation of four organophosphorus insecticides such as malathion, phosdrin (mevinphos), birlane (chlorfenvinphos), and gardona (tetrachlorvinphos) on LH-induced in vitro germinal vesicle breakdown (GVBD) in the oocytes of Mystus vittatus was investigated using three concentrations for each insecticide. All of these insecticides could significantly inhibit the LH-induced GVBD in all of their concentrations except two lower concentrations of birlane. A probable mechanism of inhibition of reproduction by these insecticides is discussed in the light of present findings.