Anti Diabetic and Hypolipidemic Activity of Bark of Ethanolic Extract of Ougeinia Oojeinensis (ROXB.).

The hypoglycemic and hypolipidemic effect of Ethanolic extract of Ougeinia oojeinensis (200mg/kg) bark was evaluated with measurements including, Body weight, blood glucose level, urine glucose and biochemical parameters. The ethanolic extracts of the powdered bark was tested for its efficacy in alloxan-induced diabetic rats. Animals were induced for diabetes with Alloxan (150 mg/kg of body weight- i.p.) and treated orally with Ethanolic extract of Ougeinia oojeinensis. The extracts were also evaluated for acute oral toxicity studies and its effect on different biochemical parameters. The extracts showed significant (p<0.01) antihyperglycemic and hypolipidemic activity as compared to diabetic control. The extract shows beneficial effects on blood glucose and urine glucose level. It also reduces the elevated biochemical parameters such as triglycerides (TGL), low density lipoprotein (LDL), very low density lipoprotein (VLDL), Total Cholesterol (TC) and increased the reduced level of high density lipoprotein (HDL) and body weight, which might be due to presence of steroids, tannins, alkaloids and triterpenoids present in that extract. Thus ethanolic extract could serve as good oral hypoglycemic agents and seems to be promising for the development of phytomedicines for diabetes mellitus.

Placental 11beta-hydroxysteroid dehydrogenase type 2 is reduced in pregnancies complicated with idiopathic intrauterine growth Restriction: evidence that this is associated with an attenuated ratio of cortisone to cortisol in the umbilical artery.

The placental 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) serves as a functional barrier to protect the fetus from excessive exposure to high levels of maternal cortisol. There is evidence that placental 11beta-HSD2 is reduced in pregnancies complicated with intrauterine growth restriction (IUGR), but the relationship between the two is uncertain owing to other maternal complications often associated with this pathological condition of pregnancy. To gain insight into the role of placental 11beta-HSD2 in the pathogenesis of IUGR, we studied variations in the activity and expression of this important enzyme as well as its functional indicator, the ratio of cortisone to cortisol in umbilical cord blood, in a cohort of 12 term deliveries complicated with idiopathic IUGR and 12 term controls. We showed that both placental 11beta-HSD2 activity and mRNA were reduced in IUGR. This was accompanied by a decrease in the ratio of cortisone to cortisol in the umbilical artery, suggesting that not only placental but also fetal 11beta-HSD2 activity may be compromised in idiopathic IUGR. Given that we previously identified the nuclear receptor PPARdelta as a potent suppressor of placental 11beta-HSD2, we also tested but found no evidence to support the hypothesis that placental PPARdelta expression is increased in IUGR thereby contributing to the molecular mechanisms that underlie the attenuated placental 11beta-HSD2. Taken together, our present findings provide evidence suggesting a role for an attenuated placental as well as fetal 11beta-HSD2 in the pathogenesis of IUGR.

11beta-hydroxysteroid dehydrogenase and glucocorticoid receptor messenger RNA expression in porcine placentae: effects of stage of gestation, breed, and uterine environment.

Glucocorticoids are known to influence many aspects of prenatal development. Three important regulators of glucocorticoid actions at the cellular level are the enzymes 11beta-hydroxysteroid dehydrogenase type 1 (11betaHSD-1), 11beta-hydroxysteroid dehydrogenase type 2 (11betaHSD-2), and glucocorticoid receptors (GR). The present study was conducted to determine the presence of these regulators in porcine placentae during early gestation (Days 24-40; term = 114 days) and to examine the influence of breed and uterine environment. Three pig models differing in uterine environment as reflected by embryonic survival from Days 24 to 40 were used: intact white cross-bred gilts (WC-INT); white cross-bred gilts that had been unilaterally hysterectomized-ovariectomized before puberty (WC-UHO); and intact Meishan gilts (ME). Porcine-specific partial cDNAs for 11betaHSD-1 and 11betaHSD-2 and a cRNA for GRalpha were developed and used to produce 32P-labeled probes for Northern blot analyses. The 11betaHSD dehydrogenase activity was measured in vitro at saturating concentrations of substrate and coenzyme. At Day 24 of gestation, 11betaHSD-2 mRNA, dehydrogenase activity, and GR mRNA were present, but 11betaHSD-1 mRNA was absent. All three mRNAs and dehydrogenase activity increased (P < 0.01) by Day 40. On Day 30, placental 11betaHSD-2 mRNA was decreased (P = 0.03) by 47% in WC-UHO versus WC-INT. Placental 11betaHSD dehydrogenase activity was 2-fold greater (P < 0.01) in ME versus WC-INT on Day 24 of gestation. These results demonstrate, to our knowledge for the first time, the presence of 11betaHSD-1, 11betaHSD-2, and GR mRNA as well as 11betaHSD dehydrogenase activity in the porcine placenta during early pregnancy. Moreover, a role for glucocorticoids in porcine embryonic development is suggested.

Changes in the expression of genes encoding steroidogenic enzymes in the channel catfish (Ictalurus punctatus) ovary throughout a reproductive cycle.

In vertebrates, the growth and maturation of the ovarian follicle is dependent on the appropriate dynamics of sex steroid secretion, which is dictated by gene expression of the steroidogenic enzymes. The molecular aspects of steroid regulation are poorly understood in fishes, so as a first step we determined the pattern of expression of four key steroidogenic genes throughout the ovarian cycle in an annually spawning teleost, the channel catfish (Ictalurus punctatus). The abundance of transcripts encoding 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) and cholesterol side chain cleavage (P450(scc)), 17 alpha-hydroxylase/lyase (P450(c17)), and aromatase (P450(arom)) were determined by rtqRT-PCR or ribonuclease protection assay and correlated to ovarian growth and plasma titers of estradiol (E(2)) and testosterone (T) in two populations of catfish. Elevations in transcript abundance for P450(c17), P450(scc), and P450(arom) were observed at the onset of ovarian recrudescence and during early vitellogenic growth of the oocytes; however, all three decreased precipitously with the completion of vitellogenesis. Changes in the expression of these genes strongly suggest a direct correlation to E(2) and T titers. Alternatively 3 beta-HSD transcript abundance was relatively stable throughout the year. This study suggests that the genes encoding the three steroidogenic cytochrome P450s have a similar regulatory mechanism.

Characterization of a pituitary GnRH-receptor from a perciform fish, Morone saxatilis: functional expression in a fish cell line.

Gonadotropin-releasing hormones (GnRHs) bind to the specific receptor present on the gonadotrophs to activate the synthesis and release of gonadotropins (follicle stimulating hormone or FSH and luteinizing hormone or LH), which in turn control gonadal maturation, gametogenesis and gamete release. Perciform species have three endogenous GnRHs. The main objective of this study was to characterize the gonadotropin-releasing hormone receptor (GnRH-R) present in the pituitary of a perciform species, striped bass (Morone saxatilis) and demonstrate how it interacts with its potential ligand. In this study, a cDNA for GnRH-R from the pituitaries of striped bass was cloned. The cloned cDNA has an open reading frame (ORF) that codes for a 419 amino acids peptide. Like other G-protein coupled receptors including the non-mammalian GnRH-Rs, the peptide has seven putative transmembrane domains and a C-terminal tail. Comparative analysis of the amino acid sequence of striped bass (stb) GnRH-R shows 38-87% similarity with the known GnRH-Rs. A Northern blot analysis revealed a single GnRH-R transcript in the pituitary; however, its expression in various extrapituitary tissues was demonstrated by a reverse-transcription-PCR (RT-PCR). Functionally, upon induction by endogenous forms of GnRHs (seabream, chicken II and salmon GnRHs) and a mammalian GnRH-agonist, the recombinant stbGnRH-R mediated a reporter gene (luciferase) activity in a fish cell line (CHSE-214). A real-time relative quantitation method established that significantly higher (P<0.05) levels of stbGnRH-R mRNA were present in the pituitaries of striped bass with advanced stages of ovarian development, compared to the pituitaries of fish with less developed ovaries.

11beta-hydroxysteroid dehydrogenase type 2 is the predominant isozyme in the guinea pig placenta: decreases in messenger ribonucleic acid and activity at term.

The type 2 isozyme of 11beta-hydroxysteroid dehydrogenase (11beta-HSD2) is responsible for inactivating physiologically active glucocorticoids to their inert metabolites. This is the predominant 11beta-HSD isozyme in the human placenta, where it is believed to protect the fetus from high levels of maternal cortisol. Given the similarity in placental structure between the human and the guinea pig (hemomonochorial), we have evaluated the potential of utilizing the guinea pig as a model to study the function and regulation of placental 11beta-HSD2 in fetal development. In this study, we characterized the intrinsic properties of 11beta-HSD in the guinea pig placenta during late pregnancy. The 11beta-HSD activity in the placenta was characteristic of 11beta-HSD2 in that it possessed only dehydrogenase activity that was NAD-dependent and had a high affinity for cortisol (Km = 134 nM). Moreover, the level of the 11beta-HSD2-like activity decreased significantly at term. To verify the expression of 11beta-HSD2 gene and to determine whether corresponding changes in 11beta-HSD2 mRNA occur at term, we also cloned the cDNA encoding guinea pig placental 11beta-HSD2. The deduced guinea pig 11beta-HSD2 enzyme contains 395 amino acids and shares over 80% sequence identity with other mammalian 11beta-HSD2 proteins. Northern blot analyses demonstrated the presence of the mRNA for 11beta-HSD2 but not that for 11beta-HSD1. Moreover, the level of 11beta-HSD2 mRNA decreased significantly at term. The parallel decrease in levels of 11beta-HSD2 activity and mRNA at term is consistent with, and provides a plausible molecular basis for, the previously reported increase in the rate of placental transfer of cortisol between mother and fetus at that time. In conclusion, the present study demonstrates that the guinea pig resembles the human in that 11beta-HSD2 is the predominant, if not exclusive, isozyme expressed in the placenta. Therefore, the guinea pig appears to represent a suitable model in which to study the role of placental 11beta-HSD2 in human fetal development.

Metyrapone is a competitive inhibitor of 11beta-hydroxysteroid dehydrogenase type 1 reductase.

The present study was designed to examine the effects of metyrapone in vitro on the activities of 11beta-hydroxysteroid dehydrogenase (11beta-HSD) types 1 and 2, the two intracellular enzymes responsible for the metabolism of glucocorticoids. Enzymatic activities of 11beta-HSD1 and 2 were determined by a radiometric conversion assay using cortisol and cortisone as physiological substrates. The enzyme activity assays were carried out in the absence and presence of metyrapone using sheep liver and kidney microsomes as the source of 11beta-HSD1 and 2, respectively. It was found that metyrapone inhibited the reductase activity of 11beta-HSD1 in a dose-dependent manner with an apparent Ki of 30 microM. Moreover, this inhibition was competitive because the Km for cortisone was increased in the presence of metyrapone. In contrast, metyrapone showed biphasic effects on the dehydrogenase activity of 11beta-HSD1, in that it increased the activity at concentrations lower than 100 microM but decreased it at higher concentrations. However, under similar conditions, metyrapone had little effect on the unidirectional dehydrogenase activity of 11beta-HSD2. In conclusion, the present results provide the first direct evidence that metyrapone is a competitive inhibitor of 11beta-HSD1 reductase, and that it also exerts biphasic effects on 11beta-HSD1 dehydrogenase activity. These findings indicate that metyrapone influences peripheral glucocorticoid metabolism through its regulation of 11beta-HSD1 activity, in addition to its classic inhibitory effects on adrenal steroid biosynthesis. It is therefore imperative that this novel extra-adrenal effect of metyrapone be considered when this drug is used in the diagnosis and treatment of adrenocorticoid-related diseases.

Biosynthesis in vivo and excretion of cortisol by fish larvae.

There is a posthatching rise in levels of endogenous cortisol during the ontogeny of those teleosts studied to date. This is thought to be the result of de novo synthesis of cortisol by the larvae, although there is no direct evidence for this. The present study aimed to demonstrate this process in Asian seabass (Lates calcarifer). Larvae (4 days posthatching) were maintained for up to 12 hours in seawater containing [3H]17 alpha-hydroxyprogesterone. High performance liquid chromatography analysis of extracts of the medium, before and after treatment with glucuronidase, indicates conversion of the precursor to several metabolites. One of these was identified as cortisol on the basis of its isopolarity with authentic standard in thin-layer chromatography, and confirmed by recrystallisation to constant specific activity. Immunohistochemistry on siblings shows that the interrenals are immunoreactive for adrenodoxin (adrenal ferredoxin) and cytochrome P-450(21) (steroid 21-monooxygenase [steroid, hydrogen-donor:oxygen oxidoreductase, 21-hydroxylating]; EC 1.14.99.10), and the pituitary for adrenocorticotrophic hormone. These findings suggest that the pituitary-interrenal axis is functional even at this early stage, and are consistent with the hypothesis that the posthatching rise in endogenous cortisol levels is the result of de novo steroidogenesis.

Ontogeny of immunoreactive steroidogenic proteins (adrenodoxin and cytochrome p-450(21)) in the interrenals of the teleost Lates calcarifer.

Antisera against bovine adrenodoxin and cytochrome P-450(21) (steroid 21-hydroxylase) cross-reacted with the interrenal cells of the adult Asian seabass (Lates calcarifer); the cells were arranged as cords, two cells thick, in the headkidney. During larval development, cells immunoreactive for adrenodoxin were first observed 1 day posthatching (dph); immunoreactivity for cytochrome P-450(21) was first detected at 1.5 dph. Initially, the interrenal cells occurred as a mass in each headkidney, which only became identifiable histologically at 5 dph. The number of interrenal cells increased with age, becoming associated with the cardinal veins at 14 dph. The present study thus indicates that the posthatching rise in cortisol may originate from the nascent interrenal tissue.