Using cultured Y-1 mouse adrenal tumor cells which produce the steroid 20(-hydroxypregn-4-en-3-one (20-DHP), it was found that 10-5 M corticosterone and deoxycorticosterone increased basal and inhibited ACTH-induced 20-DHP production. The steroid effects were concentration-dependent, reversible, and specific since six other steroids did not stimulate steroidogenesis and varied in their ability to inhibit ACTH-induced steroidogenesis. Cytochalasin D inhibited steroid-stimulated 20-DHP production, suggesting a mechanism of steroid stimulation similar to that of ACTH. Steroidogenesis stimulated by cholera toxin, (Bu) 2 cAMP, or pregnenolone was not inhibited by exogenous steroid; corticosterone increased basal and inhibited ACTH-induced intracellular cAMP production. Steroids altered cell surface morphology. These findings suggest that steroids alter adrenal steroidogenesis by acting within the plasma membrane.

The mineralocorticoid hormone, aldosterone, classically acts via the Mineralocorticoid Receptor (MR) to promote sodium transport in aldosterone target tissues, such as the kidney, thereby controlling long-term electrolyte homeostasis and blood pressure (BP). Aldosterone biosynthesis by the adrenal gland is regulated by a negative feedback loop called the Renin Angiotensin Aldosterone System (RAAS). The glucocorticoid cortisol (corticosterone in rodents), which has a very similar structure to aldosterone, shares with aldosterone an equal affinity for the MR. Typically, plasma cortisol levels are approximately 1000-fold higher than plasma aldosterone, and so the ligand specificity for aldosterone must be imposed on MR by other, non-structural, means. This specificity is important in order to retain electrolyte and BP balance within the control of the RAAS. The co-localisation of the enzyme 11β-Hydroxysteroid Dehydrogenase Type 2 (11β-HSD2) with the MR in aldosterone target tissues provides the MR with the aldosterone specificity it inherently lacks. 11β-HSD2 achieves this by converting active cortisol to its inactive 11-keto metabolite, cortisone (dehydrocorticosterone in rodents). In humans with the monogenetic Syndrome of Apparent Mineralocorticoid Excess (SAME), inactivating mutations in the HSD11B2 gene allows cortisol unregulated access to the MR. Resultant symptoms include severe hypertension and life-threatening hypokalemia. Individuals heterozygous for SAME display no overt phenotypes. However, some studies have associated SAME heterozygosity and loss-of-function polymorphisms within the HSD11B2 gene with essential and/or salt-sensitive hypertension in the general population. Targeted disruption of the Hsd11b2 gene in mice (Hsd11b2-/-) faithfully reproduces with all the major phenotypes of SAME patients. Mice heterozygote for the targeted gene (Hsd11b2+/-) have no phenotype and display a normal BP. In the present study, Hsd11b2+/- mice were used to explore the relationship between reduced 11β-HSD2 enzyme activity and salt-sensitive hypertension. On a high salt diet, Hsd11b2+/- mice were found to have increased BP and impaired natriuresis, compared to wild-type controls (Hsd11b2+/+). Further studies used pharmacological blockade of the Epithelial Sodium Channel (ENaC) and MR to ascertain the contributions of these pathways towards the observed phenotypes. These identified a deregulation of ENaC activity pertaining to an inability to regulate sodium appropriately. Investigations into the contributions of the RAAS and the Hypothalamus Pituitary Adrenal (HPA) axis have revealed valuable insights into their roles in this model. There is an implication that the RAAS has increased sensitivity in Hsd11b2+/-, further exacerbated by increased dietary sodium, and that the regulation of corticosteroids may also be altered. Novel observations have suggested that oxidative stress in response to a high salt diet could also be involved, as a study administering an antioxidant drug in conjunction with a high salt diet prevented the manifestation of a phenotype in Hsd11b2+/-. Finally, the generation of a floxed Hsd11b2 targeting construct for tissue-specific deletion of 11β-HSD2 will allow future studies into the contributions of specific 11β-HSD2 expression sites (such as the kidney) towards the phenotypes of both homozygous and heterozygous mice.

Introduction: Neuroactive steroids represent a class of both synthetic and naturally occurring steroids that have an effect on neural function. In addition to classical genomic mechanism by the hormones progesterone, deoxycorticosterone and testosterone 3α-OH metabolites of these hormones enhance GABAA receptor through rapid non-genomic mechanism. The site(s) of action of these neuroactive steroids namely 3α-OH-5α-pregnan-20 one, (3α,5α)-3,21-deoxycorticosterone(3α5α-THDOC) and 5α androstane-3α,17β-diol on GABAA receptor are distinct from that of benzodiazepines and barbiturate binding sites. The modulation site(s) has a well-defined structure activity relationship with a 3α-hydroxy and a 20-ketone configuration in the pregnane molecule required for agonistic action. Pregnenolone sulfate is a noncompetitive GABAA receptor antagonist and inhibit GABA activated Cl- current in an activation dependant manner. 3β-hydroxy A-ring reduced pregnane steroids are also GABAA receptor antagonist and inhibit GABAA receptor function and its potentiation induced by their 3α-diesteromers in a noncompetitive manner. Aim: The aim was to investigate if the effect of GABA, pentobarbital antagonism by bicuculline and if the effect of GABA-agonist and antagonist neuroactive steroids including pregnenolone sulfate is dependant on the α-subunits of GABAA receptor. Furthermore, the studies aimed at investigating the binding site of pregnenolone sulfate and if its effect is dependent on γ-subunit. In addition, the inhibitory effect of pregnenolone sulfate and 3β-hydroxy steroids has been characterized. We also wanted to investigate if the neuroactive steroids effect vary between the human and rat recombinant α1β2γ2L receptors and between the long (L) and short (S) variants of γ2-subunit. Method: Experiments were performed by the two electrodes voltage-clamp technique using oocytes of Xenopus laevis expressed with recombinant GABAA receptors containing α1, α4 or α5, β2, γ2L and γ2S-subunits. Results: There was no difference between the α1, α4 and α5-containing subunits regarding GABA and pentobarbital inhibition by bicuculline. GABA-activated current in the binary αβ was potent than that of ternary αβγ receptor. Unlike Zn2+ effect, inhibition by pregnenolone sulfate on the GABAA receptor is not dependant on the γ-subunit. It is likely that the 2’ residue closest to the N-terminus of the protein at M2 helix on both α1 and β2 subunit are critical to the inhibitory actions of PS and the function of Cl- channels. Point mutation at M2 helix of the β2-subunit (b2A252S) can dramatically reduce the inhibitory effect of PS on the GABAA receptors without affecting the inhibitory properties of 3β-hydroxysteroids. Agonist and antagonist steroids also varied in their efficacy between the human and rat α1β2γ2L receptor. Neuroactive steroids also showed difference between human γ2L and γ2S-containing receptor. Conclusions: GABA and pentobarbital antagonism by bicuculline is not dependant on α-subunit. Pregnenolone sulfate binding site is different from that of Zn2+. 3β-hydroxysteroids and pregnenolone sulfate inhibit GABAA receptor through different mechanisms. Neuroactive steroids also differ between species and between the long and short variant of γ- subunit.

Young female rats treated with trenbolone demonstrated an increase in weight gain per day and overall weight increase during the treatment period. Trenbolone treated rats also experienced improved feed efficiency. Muscles removed from the lower hind limb of trenbolone treated rats had a greater DNA to protein ratio than muscles from control animals. However, there was no significant difference in wet muscle weight between trenbolone treated and control muscles. Satellite cells from untreated female rats were not responsive to trenbolone added in vitro. In studies utilizing serum free medium, trenbolone alone, and in the presence of growth factors, could not stimulate proliferation above controls. In similar serum free medium studies, satellite cells from trenbolone treated rats were more responsive to growth factors than cells from control rats.

No description available.

This report examines differences in risk of myocardial infarction and stroke (cardiovascular events) between the cyclooxygenase-2 (COX-2) inhibitors Rofecoxib, Celecoxib, and Valdecoxib, and the traditional nonsteroidal anti-inflammatory agents (NSAIDs) Naproxen and Ibuprofen, as well as Meloxicam, a preferential COX-2 inhibitor. The population studied was the DoD TRICARE beneficiary population greater than age 40 during the study period. In September of 2004, Rofecoxib was removed from the market due to an increased risk of cardiovascular events. In February of 2005, the Food and Drug Administration (FDA) examined the entire class of COX-2 inhibitors and recommended that Valdecoxib also be withdrawn from the market. According to Department of Defense TRICARE prescription records, COX-2 inhibitor prescription numbers were increasing rapidly and more than $7 million was spent on these agents alone in July of 2004. Logistic regression was used to analyze TRICARE prescription and diagnosis data from calendar years 2002, 2003, and 2004 for cardiovascular event risk comparisons among various NSAIDs. Rofecoxib was found to have a significantly increased risk of cardiovascular events when compared with all other medications in the study, including Valdecoxib. Odds ratios for comparison with Valdecoxib, Celecoxib, Meloxicam, Ibuprofen, and Naproxen were 1.09, 1.14, 1.15, 1.28, and 1.23. Valdecoxib showed a significant increase compared to Ibuprofen, Naproxen, and Celecoxib (odds ratios 1.21, 1.16, and 1.06). Ibuprofen showed a significantly decreased risk relative to all medications except Naproxen. When considering only cardiovascular risk, this study suggests prescribers should consider Ibuprofen or Naproxen as the primary agent of choice, with Meloxicam, and Celecoxib as reasonable second choices. Ultimately, the decision must also weigh the patient's risk of gastrointestinal side effects and cost of therapy.

A dissertation submitted to the Faculty of Science, University of' the Witwatersrand, in partial fulfilment of the requirements of the Degree of Master of Science in the field ·of Biotechnology. February 1991. / Nocardioform bacteria were studied for their ability to interconvert bile acids. From the studies of utilisation and resistance curves, the most suitable donor and recipient strains for complementary gene cloning, were Arthrobacter oxydans strain C1 and Rhodococcus erythropolis strain ATCC 4217-1 respectively. [Abbreviated Abstract. Open document to view full version] / MT2016

Foi estudada a atividade ovariana de fêmeas de onça-pintada (Panthera onca; adultas n=2 e pré-púberes n=3) mantidas em cativeiro, pela extração e quantificação de estrógenos e progestinas fecais. Foram colhidas amostras fecais de 2-7 vezes por semana durante 16-18 meses. Foi realizada a validação dos radioimunoensaios em fase sólida, progesterona e 17β-estradiol, para uso em extratos fecais em onça-pintada. A duração média (±EPM) do ciclo ovariano (n=7) definido por dois picos consecutivos de estrógenos fecais foi de 38,28 ±2,52dias (variando de 25 a 44 dias). A fase de estro teve duração média de 10,42 ±1,15dias (variando de 7 a 15dias) e a fase de inter-estro durou em média 28,00 ±1,43dias (variando de 28 a 31 dias). O nível basal médio de estrógenos fecais no período de inter-estro foram de 31,26 ±1,34ng/g de fezes secas. No período de estro, os valores médios encontrados foram de 115,91 ±8,82ng/g de fezes secas, foi observado um pico entre o D-5 e o D-2, com valores médios de 164,45 ±3,49ng/g de fezes secas. As progestinas fecais apresentaram valores médios de 0,44 ±0,05µg/g de fezes secas, não apresentando variações significantes durante todo o ciclo. Os dados obtidos durante a avaliação do perfil longitudinal das concentrações de estrógenos fecais, no grupo dos animais pré-púberes, permitem indicar um possível início da atividade ovariana a partir do bimestre agosto-setembro, onde os valores médios dos picos detectados para estrógenos fecais, foram de 135,31 ±3,16ng/g de fezes secas. Todos os animais entraram na fase peripuberal com idade aproximada de 20 meses. / Ovarian function of captive jaguars (Panthera onca; adults n=2 and pre-pubertal n=3) was assessed by extraction and quantification of fecal estrogens and progestins. Fecal samples were obtained 2-7 times per week during 16-18 months. Validation of solid phase radioimmunoassay for progesterone and 17β-estradiol was performed for jaguar fecal extracts. Ovarian cycle mean duration (±SEM), defined by two consecutive peaks of fecal estrogens, was 38.28 ±2.52days (range, 25 - 44days; n=7). Mean estrous phase duration was 10.42 ± 1.15days (range, 7 - 15days), and inter-estrous phase mean duration was 28.00 ±1.43days (range, 28 - 31days). Basal fecal estrogen mean concentration in inter-estrous period was 31.26 ± 1.34ng/g of dry feces. During estrous period mean value was 115.91 ±8.82ng/ g of dry feces, and was observed a mean peak (164.45 ±3.49 ng/g of dry feces) between D-5 and D-2. Fecal progestins had a mean concentration of 0,44 ± 0.05µg/g of dry feces, with no significant variations during the cycles. Data obtained during the evaluation of fecal estrogen longitudinal profiles in the pre-pubertal group, allow to indicate the beginning of ovarian activity in August-September bimester with fecal estrogen mean peaks of 135.31 ± 3.16ng/ g of dry feces. AlI animaIs started pre-pubertal phase around 20 months of age.

Os metais podem causar efeitos adversos de grande amplitude na função reprodutiva de animais, principalmente em organismos aquáticos. Eles podem alterar o sistema endócrino, atuando na esteroidogênese, afetando o processo reprodutivo dos peixes. Nosso objetivo foi investigar os efeitos dos metais alumínio (Al) e manganês (Mn) em pH ácido sobre a esteroidogênese de machos de Astyanax bimaculatus, sexualmente maduros, após uma exposição aguda de 96 horas e avaliar se os animais foram capazes de recuperar dos possíveis efeitos destes metais em água livre de metais. Esses animais foram expostos a uma concentração nominal de 0,5 mg.L-1 de Al e Mn (isolados ou combinados), e os grupos experimentais foram mantidos em pH ácido (5,5) para manter os metais biodisponíveis. Foi realizada uma exposição aguda de 96 horas, com amostragens em 24h e 96h, e depois também um período de 96h em água livre de metais, com amostragens em 120h e 192h, a partir do o início do experimento. Foram determinadas as concentrações plasmáticas de testosterona (T), 11-cetotestosterona (11-KT), 17β-estradiol (E2) e cortisol (C) por ELISA. Além disso, foram realizadas análises histológicas dos testículos e avaliação da concentração espermática. Os metais estudados, além do pH ácido, foram capazes de aumentar as concentrações plasmáticas dos androgénos T e 11-KT. Também foi observado um aumento transitório de E2 em 24h, mas apenas em animais expostos ao Mn e depois uma diminuição em 96h. A exposição ao pH ácido e metais, sozinhos ou combinados não provocou alterações nos níveis de C. Sendo assim, Al e Mn , assim como a acidez da água podem atuar como desregulador endócrino em machos de A. bimaculatus, principalmente por estimulação da síntese de androgénos, causando alterações no sistema fisiológico. No entanto, 96 horas não foram suficientes para que os animais se recuperassem. Os testículos encontravam-se em estágio avançado de maturação, enquanto que a concentração espermática não apresentou alterações significativas que indicassem a atuação dos metais em conjunto ao pH ácido. Táticas reprodutivas podem ter sido utilizadas pela espécie para desencadear alterações na esteroidogênese testicular, principalmente acelerando o processo de espermatogênese e espermiogênese, o que pode interferir com a dinâmica reprodutiva / Metals can cause adverse wide range effects on reproductive function of animals, mostly in aquatic organisms. They can alter the endocrine system, acting on gonadal steroidogenesis, affecting the reproductive process of fish. We aimed to investigate the effects of the metals aluminum (Al) and manganese (Mn) in acidic pH on the steroidogenesis of Astyanax bimaculatus males, sexually mature, after an acute exposure of 96 hours and evaluate if the animals were able to recover of the possible effects of these metals in the water free of metals. Mature males were exposed to a concentration of 0.5 mg.l-1 of Al and Mn (isolated or combined) and the experimental groups were maintained at acidic pH (5.5) to keep the metals bioavailable. We performed an acute exposure of 96 hours, with samplings at 24h and 96h, and then also a period of 96h in water free of metals, with samplings at 120h and 192h from the beginning of the experiment. We measured the plasma levels of testosterone (T), 11-ketotestosterone (11-KT), 17?-estradiol (E2) and cortisol (C) by elisaimmunoassay. Furthermore, histological analysis of testes and evaluation of the sperm concentration were performed. The metals studied, in addition to acidic pH, were able to alter the plasma concentration of the androgens T and 11KT. A transitory increase (24h) of E2 levels was also observed, but only in animals exposed to Mn and then a decrease in 96h occurred. Exposure to acidic pH and metals, alone or combined did not trigger changes in C plasma levels. Generally, Al and Mn as well as the acidity of water can act as endocrine disruptor in A. Bimaculatus males, mainly by stimulating the androgens synthesis, causing changes on physiological system. However, 96 hours in water free of metals were not enough for the animals to recover from the effects of the metals. The testes were in the advanced stage of maturation, while sperm concentration was not significantly changed to suggest any influence of metals together with acidic pH in altering this variable. Reproductive tactic could be used by the species to trigger changes in testicular steroidogenesis, mainly accelerating the process of spermatogenesis and spermiogenesis, what may interfere with the reproductive dynamics

O presente estudo teve como objetivo utilizar a técnica de enzimaimunoensaio (EIE) com o Ac monoclonal CL425 na dosagem de metabólitos de progestinas fecais para caracterizar o perfil no início da atividade ovariana e durante o ciclo estral em onça pintada (Panthera onca) e durante a gestação e lactação em gato mourisco (Puma yagouaroundi). Foram estudadas três fêmeas de onça pintada em fases distintas (pré-puberes n=2 e adulta n=1) e três fêmeas de gato mourisco em duas fases distintas (gestantes n=2 e lactantes n=3). O protocolo empregado no EIE foi validado para a mensuração de progestinas em fezes de onça pintada e gato mourisco (r=0,98, p=0,0078; r=0,97, p=0,0130, respectivamente). Observou-se que os animais pré-puberes apresentaram início da produção de progesterona nos meses de setembro e novembro. As elevações das progestinas fecais na fêmea adulta de onça pintada não se sustentaram, indicando que não ocorreu ovulação espontânea nessa espécie. Houve diferença significativa entre as concentrações médias de progestinas fecais (p<0,001) dos animais pré-púberes e adultos no grupo das fêmeas de onça pintada. No grupo das fêmeas de gato mourisco, não foi possível diferenciar as concentrações de progestinas fecais durante a gestação e lactação.Obtivemos correlação entre as concentrações de progestinas fecais medida pelos métodos de radioimunoensaio (RIE) e enzimaimunoensaio (r=0,98, p<0,0001). / The present study had as objective to use the technique of enzyme immunoassay (EIA) with monoclonal antibody CL425 in the dosage of faecal progestin to characterize the profile during ovarian activity beginning and estral cycle in jaguar (Panthera onca) and gestation and lactation in jaguarondi (Puma yagouaroundi). Three female jaguars were studied in distinct phases (pre-pubertal n=2 and adult n=1) and three female jaguarondi were studied during two distinct phases (gestation n=2 and lactation n=3). The EIA used was validated for faecal progestin measurement in jaguar and jaguarondi (r=0,98, p=0,0078; r=0,97, p=0,0130, respectively). The beginning of progesterone production for pre-pubertal animals was in September and November. Elevations of progestin in the adult jaguar were not supported, showing that there was not spontaneous ovulation for this specie. There was significant difference between medium progestin concentrations (p<0,001) of pre-pubertal and adult jaguars. It was not possible to identify different progestin concentrations during gestation and lactation in female jaguarondi. The faecal progestin profiles measured by radioimmunoassay (RIA) and enzyme immunoassay (EIA) corresponded well and were positively correlated (r=0,98, p<0,0001).