Browsing by Author "S. Haider"

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Alcohol inhibition of formalin induced depletion of neurosecretory material in the teleost Clarias batrachus (L.)
(1975) S. Haider; A.G. Sathyanesan
In the normal C. batrachus a fair amount of stainable neurosecretory material (NSM) is always present in all the component parts of the hypothalamo neurohypophysial (NH) complex. When formalin was injected intraperitoneally 70 to 90% of the NSM was depleted from the HN complex. When ethyl alcohol was administered immediately after formalin treatment, the depletion of NSM was inhibited, and their staining intensity could be compared with those of untreated controls.
Antagonistic response of chlorpromazine and formalin in effecting quantitative changes in the neurosecretory material in the teleost Clarias batrachus (L.)
(1975) S. Haider; A.G. Sathyanesan
[No abstract available]
Changes in total cAMP levels during oocyte maturation in the catfish, Clarias batrachus
(1995) S. Haider; Shail K. Chaube
Oocyte maturation (meiosis reinitiation) in the catfish (Clarias batrachus) is induced by maturation-inducing steroid (MIS), 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-DP). The results of the present study demonstrate the possible involvement of cAMP in oocyte maturation in vivo or induced by 17α,20β-DP in vitro. Measurement of total cAMP levels at different morphological stages of oocytes obtained under in vivo conditions showed a significant reduction between the values at the centrally located germinal vesicle (C-GV), subperipheral (SP-GV), peripheral (P-GV), and germinal vesicle breakdown (GVBD) stage. In the time course study, MIS-treated oocytes showed a significant reduction in the total cAMP level at 2 hr and maintained it up to the duration of the study (24 hr). These results suggest that a decrease in the cAMP level within the follicle triggers oocyte maturation in this species. The in vitro effects of the adenylate cyclase activator, forskolin, and the phosphodiesterase inhibitor, theophylline, on 17α,20β-DP-induced GVBD was also investigated. Both substances inhibited 17α,20β-DP-induced GVBD, suggesting indirectly the inhibitory role of cAMP in catfish oocyte maturation. © 1995.
Cyclic AMP level and phosphodiesterase activity during 17α,20β-dihydroxy-4-pregnen-3-one induction and theophylline inhibition of oocyte maturation in the catfish, Clarias batrachus
(Elsevier Inc., 2003) S. Haider
This study directly tested the hypothesis that the induction of oocyte maturation in the catfish Clarias batrachus is followed by a transient decrease in oocyte cyclic AMP (cAMP) level that is due to an increase in phosphodiesterase (PDE) activity. Further, the PDE inhibitor theophylline was used to investigate the possible role of PDE in the maturation-inducing action of 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-DP), the physiological maturation-inducing steroid of this catfish species. The results obtained from batches of oocytes taken from the same donor at the same time clearly show a close relationship between dose-dependent induction of germinal vesicle breakdown (GVBD) and PDE activity with a concomitant decrease in cAMP in the oocytes treated with different concentrations of 17α,20β-DP. In contrast, theophylline prevents GVBD and inhibits PDE activity by promoting cAMP accumulation in oocytes. A time-dependent decrease in PDE activity and an increase in cAMP content with a marked inhibition of GVBD were recorded even in oocytes pre-stimulated with 1 μg/ml 17α,20β-DP for 6 h and then treated with 1 mM theophylline for various times. These results suggest that cAMP plays a key role in the regulation of oocyte maturation in C. batrachus which may be mediated by PDE activity. © 2002 Elsevier Science Inc. All rights reserved.
Cyclic AMP-mediated control of oocyte maturation in the catfish, Clarias batrachus (Bloch): Effects of 17α,20β-dihydroxy-4-pregnen-3-one and phosphodiesterase inhibitors
(2000) S. Haider; S.S.R. Baqri
An increase in the percentage of germinal vesicle breakdown (GVBD) with a corresponding decrease in cAMP was found in the oocytes which were incubated for 36 hr with different concentrations of 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-DP). At its highest concentration (1μg/ml), 17α,20β-DP induced 91.9 ± 2.3% GVBD and decreased cAMP level to 0.8 ± 0.1 pmol/oocyte from 2.9 ± 0.2 pmol/oocyte (control). The two different known inhibitors of phosphodiesterase viz. 3-isobutyl-1-methyl-xanthine (IBMX) and theophylline inhibited GVBD in vitro and promoted the accumulation of cAMP in a dose-dependent manner irrespective of whether the oocytes were treated for a short duration (2 hr) or for a long duration (36 hr). Evaluation of time course response to 1 mM IBMX or 1 mM theophylline revealed that cAMP levels increased at all the time points when compared with their respective controls and blocked maturation. In contrast, 1 μg/ml 17α,20β-DP not only induced oocyte maturation but also caused an immediate decrease in cAMP within the first 2 hr (from 3.2 ± 1.3 to 1.3 ± 0.1 pmol/oocyte) of incubation which was maintained till the end of experiment (36 hr). Likewise, a significant inhibition of GVBD and accumulation of cAMP was recorded even in oocytes pre-stimulated with 1 μg/ml 17α,20β-DP for 6 hr and then treated with different concentrations of IBMX or theophylline. Taken together, these data strongly suggest that in C. batrachus a decrease of oocyte cAMP concentration is a prerequisite for the induction of oocyte maturation, and its increase is associated with the maintenance of meiotic arrest.
Demonstration of post-hypophysectomy changes in the neurosecretory system of a fish with in situ staining technique
(Birkhäuser-Verlag, 1969) A.G. Sathyanesan; S. Haider
[No abstract available]
Dynamics of 17α,20β-dihydroxy-4-pregnen-3-one and 17α,20β,21-trihydroxy-4-pregnen-3-one in plasma and oocyte incubation media of catfish (Clarias batrachus) in response to salmon gonadotropin
(2001) R. Moses Inbaraj; S. Haider; S.S.R. Baqri
Free and sulphated 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-DP) and 17α,20β,21-trihydroxy-4-pregnen-3-one (17α,20β,21-P) were separated by HPLC in blood plasma and oocyte incubation medium and measured by radioimmunoassay (RIA) in the female catfish, Clarias batrachus in response to salmon gonadotropin (SG-G100). A significant rise of both free (4.24 ± 0.44 ng/ml) and sulphated (46.08 ± 1.15 ng/ml) 17α,20β-DP was noticed in the plasma of SG-G100 injected fish in comparison to the respective saline control values, 1.75 ± 0.14 ng/ml and 19.59 ± 0.58 ng/ml. In the oocyte incubation medium also, SG-G100 elevated the levels of both free and sulphated 17α,20β-DP, but the level of the free steroid was much higher (131.07 ± 3.46 ng/ml) than the sulphated one (36.51 ± 2.02 ng/ml). On the other hand, levels of 17α,20β,21-P in plasma (free, 5.50 ± 0.87 vs 2.49 ± 0.69 ng/ml; sulphated, 14.31 ± 1.32 vs 1.99 ± 0.92 ng/ml) as well as in the oocyte incubation medium (free, 2.59 ± 0.4 vs 2.08 ± 0.32 ng/ml; sulphated, 2.04 ± 0.23 vs 1.44 ± 0.22 ng/ml) were much lower than that of 17α,20β-DP in response to SG-G100. The peak level of free 17α,20β-DP in the oocyte incubation medium coincides with the oocyte maturational activity (earlier observations) in C. batrachus.
Effect of chlorpromazine and morphine on the neurosecretory system of the Indian wall lizard Hemidactylus flaviviridis (Ruppell)
(1974) S. Haider
[No abstract available]
Effects of actinomycin d and cycloheximide on gonadotropin- or 17α, 20 β-dihydroxy-4-pregnen-3-one-induced in vitro maturation in oocytes of the catfish, Clarias batrachus
(Springer India, 1995) K. Balamurugan; S. Haider
The effect of inhibitors in the oocyte maturation of Clarias batrachus, was investigated in vitro using actinomycin D and cycloheximide. Full-grown immature oocytes incubated with salmon gonadotropin (SG-G100) and 17α, 20ß-dihydroxy-4-pregnen-3-one at the concentration of 1 μg/ml induced 86.0 ± 1.2% and 91.3 ± 2.4% of germinal vesicle breakdown, respectively. When the oocytes were incubated with SG-G100 (1 μg/ml) + different concentrations of actinomycin D or cycloheximide, a significant drop in the frequency of germinal vesicle breakdown was observed. Thus, gonadotropin-induced maturation was inhibited by both transcriptional and translational inhibitors. When the oocytes were incubated with 17α, 20ß-dihydroxy-4-pregnen-3-one (1μg/ml) + different concentrations of cycloheximide, a significant inhibition of germinal vesicle breakdown was recorded. However, the maturation was not inhibited when the oocytes were incubated in the presence of 17α, 20ß-dihydroxy-4-pregnen-3-one (1 μg/ml) and different concentrations of actinomycin D. This suggests that mRNA synthesis is not obligatory for 17α, 20β-dihydroxy-4-pregnen-3-one induced oocyte maturation. Based on the time course experiment, it was observed that the inhibition of maturation in cycloheximide treated oocytes extends up to 12 h after which the effect becomes slowly subdued. © 1995 Indian Academy of Sciences.
Effects of cAMP forskolin and cyanoketone on in vitro oocyte maturation in the catfish, Clarias batrachus
(Springer India, 1997) Shail K. Chaube; S. Haider
This study investigated the interactive effects of cyanoketone (CK), an inhibitor of 3β-hydroxsteroid dehydrogenase (3β-HSD), on the effects of cAMP and forskolin (FK) on oocyte maturation in Clarias batrachus using an in vitro incubation technique. When the oocytes were incubated in the presence of 1 μg/ml 17α,20β-dihydroxy-4-pregnen-3-one [17α,20β-DP, the maturation-inducing steroid (MIS) of this species] for 6 h, they matured [85.3 ± 1.36% germinal vesicle breakdown (GVBD)] normally after additional incubation for 20-30 h in plain medium. On the other hand, exposure to 1. and 8.0 mM of cAMP after MIS stimulation caused significant inhibition of GVBD but lower concentrations (0.1 and 0.5 mM) of cAMP were noninhibitory. However, when the oocytes were preincubated for 1 h with 1 μg/ml CK, a significant inhibition in the percentage of GVBD was recorded including the lower concentrations of cAMP. FK, an activator of adenylate cyclase, could significantly induce GVBD at all of its concentrations (0.1, 0.5, 1.0 and 10.0 μM) in a dose- and time-dependent manner. However, when the oocytes were exposed to 1 μg/ml CK for 1 h, prior to FK stimulation, a complete inhibition of GVBD occurred but when CK treatment was given after the FK stimulation, only a partial inhibition of maturation was observed. Taken together, these data indirectly suggest that FK induces catfish oocyte maturation probably by stimulating follicular production of Δ4 steroid (17α,20β-DP) through an adenylate cyclase-cAMP-mediated pathway, a mechanism identical to the gonadotropin-induced oocyte maturation.
Effects of cyproterone acetate and flutamide on the testis and epididymis of the Indian wall lizard, Hemidactylus flaviviridis (Ruppell)
(1986) S. Haider; U. Rai
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 Δ5-3β-hydroxysteroid dehydrogenase and glucose-6-phosphate dehydrogenase activity, was evident in the Leydig cells of CA-treated testis. Flutamide, on the other hand, has 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. © 1986.
Effects of mammalian pituitary gonadotropins and testosterone on the testes of sexually quiescent Indian wall lizard, Hemidactylus flaviviridis (Rüppell)
(1986) U. Rai; S. Haider
Effects of mammalian FSH, LH and testosterone on sexually regressed testes of Hemidactylus flaviviridis were investigated. Quantitative as well as histochemical studies revealed that only FSH could stimulate spermatogenesis and steroidogenesis. LH showed no effect either on the spermatogenesis or on steroidogenesis. Although testosterone did not induce any change at the initial stage, when given for a longer period the division of spermatogonia was completely checked. 1986 The Zoological Society of London
Effects of season, ovariectomy and mammalian gonadotropins on the oviduct of Indian wall lizard Hemidactylus flaviviridis (Ruppel)
(1985) S. Haider
[No abstract available]
Evidence for the stimulation of cyclic AMP phosphodiesterase in catfish (Clarias batrachus) oocytes by 17α,20β-dihydroxy-4-pregnen-3-one
(1997) S.K. Chaube; S. Haider
A decrease in cyclic AMP (cAMP) level within the catfish follicle occurs during oocyte maturation (Haider and Chaube [1995] Comp. Biochem. Physiol., 112A:379-385). Experiments described in this report were performed to evaluate the modulations in oocyte phosphodiesterase (PDE) activity during maturation in the catfish Clarias batrachus. An increase in PDE activity was found in extracts of oocytes which were incubated for 36 hr with different concentrations of 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-DP; the naturally occurring maturation-inducing steroid of this catfish), and this increase was in a dose-dependent manner. Evaluation of the time course of response to 1 μg/ml 17α,20β-DP revealed that PDE activity increased in a time-dependent manner. A minimum detectable PDE activity was observed at 2 hr, the half-maximal activity at 6 hr, and maximum at 36 hr of incubation of oocytes with 17α,20β-DP. The two different known inhibitors (isobutylmethylxanthine and theophylline) inhibited catfish oocyte PDE activity in a dose-dependent manner. These studies suggest that the 17α,20β-DP-induced increase in PDE is involved in the decrease in cAMP in catfish oocytes during maturation.
Experimental and seasonal changes in the pituitary of the teleost Heteropneustes fossilis (Bloch)
(1978) S. Haider
[No abstract available]
Further experimental evidence in support of the involvement of ovarian follicles in oocyte maturation of the Indian catfish, Mystus vittatus
(1990) S. Haider
The role of the ovarian follicular layer in the oocyte maturation of the Indian catfish, Mystus vittatus, was investigated in vitro using cyanoketone and epostane (specific inhibitors of the 3β-hydroxysteroid dehydrogenase enzyme system). Folliculated oocytes incubated with luteinizing hormone (LH) at the concentration of 10 μg/ml induced 67.7 ± 1.5% of germinal vesicle breakdown (GVBD). When the oocytes were incubated with LH + cyanoketone or epostane, there was a significant drop in the frequency of GVBD. It revealed that the maturational response of M. vittatus oocytes to LH depends on the synthesis of Δ4 steroids (probably 17α,20β-dihydroxy-4-pregen-3-one; 17α,20β-diOHprog) from the follicular layer since both the inhibitors failed to abolish the maturational effect of 17α,20β-diOHprog (the most potent maturation-inducing steroid for this species). © 1990.
Germinal vesicle breakdown in oocytes of catfish, Mystus vittatus (Bloch): Relative in vitro effectiveness of estradiol-17β, androgens, corticosteroids, progesterone, and other pregnene derivatives
(1986) N. Upadhyaya; S. Haider
The relative in vitro effectiveness of estradiol-17β, androgen, corticosteroids, progesterone, and other pregnene derivatives on germinal vesicle breakdown (GVBD) using folliculated oocytes of an Indian catfish Mystus vittatus was investigated. 17α,20β-Dihydroxy-progesterone was found to be the most effective maturation-inducing steroid (MIS). Estradiol-17β and testosterone were not effective but androsterone was found to be fairly effective in final oocyte maturation. Deoxycorticosterone (DOC), hydrocortisone, progesterone, and 17α-hydroxyprogesterone were also effective at their higher concentrations. Among 5β-reduced pregnenes, all but 5β-pregnene-3α-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. © 1986.
Histochemical and experimental study on the adrenal of the freshwater catfish, Ompok bimaculatus (Bloch)
(1982) A.C. Pandey; S. Haider
The adrenal tissue is situated around the cardinal vein and its branches in the pronephric head kidney. The medullary cells are largely confined to the wall of these blood vessels, whereas the cortical cells are arranged in several layers around the medullary cells. The cortical cells are eosinophilic and give positive reaction to Sudan black-B, Baker's acid haematein and Schultz's tests. In response to ACTH and thiourea treatments, the cortical cells exhibited hypertrophy, degranulation and depletion of lipid content. Pronounced cortical atrophy was evident in the hypophysectomised specimens. Marked involution was noticed in the cortical cells in response to hydrocortisone treatment. The medullary cells are larger than the cortical cells and are eosinophobic. Thgey give positive reaction to ferric-ferricyanide, PAS and ascorbic acid tests. Two types of medullary cells could be differentiated with the help of dichromate, iodate and glutaraldehyde-silver techniques. These cells did not exhibit any visible change after ACTH, hydrocortisone and thiourea treatments. However, reduction in the cellular size is obvious in the hypophysectomised fish.
Histological and histochemical study of the caudal neurosecretory system of the freshwater teleost Ompok bimaculatus (Bloch) with a note on its response to hypophysectomy and osmotic stress
(1981) S. Haider; A.C. Pandey
[No abstract available]
Hypothalamo hypophysial neurosecretory and portal system of the Indian wall Lizard, Hemidactylus flaviviridis
(1974) S. Haider; A.G. Sathyanesan
The structure and topography of the hypothalamo hypophysial complex is studied with the aid of in situ preparations and microtome sections. The supraoptic nucleus (SON) is divisible into rostral, median and caudal groups of neurons. In the ventral view the intact SON is in the form of an inverted 'V'. The neurons of the paraventricular nucleus (PVN) are more scattered peripherally, which maintains a continuity between the SON and PVN. The neurosecretory axons of PVN and SON unite and form a consolidated tract anterior to the median eminence. This tract ramifies extensively in the neural lobe and has perivascular endings. Neurosecretory axons do not penetrate into the pars intermedia. The primary capillary plexus gives rise to the portal vessels which irrigate the pars distalis. In addition to a hypophysial artery, a few portal like vessels formed from the primary plexus vascularize the neural lobe. The neural lobe is demarcated from the pars intermedia by an uninterrupted vascular septum. The active principles controlling the pars intermedia might be transferred from these bordering blood vessels to the gland cells, which is essentially a neurovascular mechanism. Direct vascular connection between the neural lobe and pars distalis is also noticed in this species. An instance of extension of the neural lobe into the third ventricle and a few cases of retention of the remnants of the orohypophysial duct are also described.