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Results for “Steroid profiling”

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At least 289 records · Page 16Linked to original sources

PubMed2005

Longitudinal profiling of urinary steroids by gas chromatography/combustion/isotope ratio mass spectrometry: diet change may result in carbon isotopic variations.

Longitudinal profiling of urinary steroids was investigated by using a gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) method. The carbon isotope ratio of three urinary testosterone (T) metabolites: androsterone, etiocholanolone, 5beta-androstane-3alpha,17beta-diol (5beta-androstanediol) together with 16(5alpha)-androsten-3alpha-ol (androstenol) and 5beta-pregnane-3alpha,20alpha-diol (5beta-pregnanediol) were measured in urine samples collected from three top-level athletes over 2 years. Throughout the study, the subjects were living in Switzerland and were residing every year for a month or two in an African country. (13)C-enrichment larger than 2.5 per thousand was observed for one subject after a 2-month stay in Africa. Our findings reveal that (13)C-enrichment caused by a diet change might be reduced if the stay in Africa was shorter or if the urine sample was not collected within the days after return to Switzerland. The steroids of interest in each sample did not show significant isotopic fractionation that could lead to false positive results in anti-doping testing. In contrast to the results obtained with the carbon isotopic ratio, profiling of urinary testosterone/epitestosterone (T/E) ratios was found to be unaffected by a diet change.

Adult↗

PubMed1976

Steroids in fluids and sperm entering and leaving the bovine epididymis, epididymal tissue, and accessory sex gland secretions.

Ten steroids which may have a role in the process of sperm maturation within the epididymis were quantified by competitive protein binding or radioimmunoassay. Rete testis fluid (RTF) carrying testicular sperm into the epididymis was rich in dehydroepiandrosterone and testosterone (21 +/- 2 and 33 +/- 3 ng/ml) while cauda eipididymal plasma (CEP) around sperm which have completed maturation had high levels of progesterone, dihydrotestosterone, 3beta-androstanediol, dehydroepiandrosterone and testosterone (7.4 +/- 0.8, 20.3 +/- 1.1, 6.5 +/- 0.4, 8.0 +/- 0.7 and 11.5 +/- 0.7 ng/ml). About 4 mug of steroids enter the epidymis daily in RTF, but less than 1% was found in CEP; the balance presumably was absorbed by the epithelium in the proximal caput epididymidis. Nevertheless, tissue levels of total 17beta-OH androgens were lower in the proximal caput than in the distal caput or corpus epididymidis. In all zones of the epididymis, dihydrotestosterone accounted fro about 70% of the total 17beta-OH androgens found in the nuclear fraction. In the cytoplasmic fraction, however, dihydrotestosterone predominated only in the distal caput and corpus epididymidis. In the cauda epididymidis, CEP and sperm probably accounted for less than 35% of the total 17beta-OH androgens and less than 25% of the dihydrotesterone. The progesterone concentration of the cauda than in the caput epidymidis. Twice washed testicular sperm contained more testosterone than cauda epididymal or ejaculated sperm (16.6 +/- 1.9, 1.6 +/- 0.2 and 1.5 +/- 0.3 ng/10(9) sperm, respectively), but less progesterone (0.5 +/- 0.1, 1.3 +/- 0.2 and 1.0 +/- 0.4 ng/10(9) sperm, respectively). As a consequence of mixture with estrogen-rich prostatic fluid (150 +/- 9 pg/ml), ejaculated sperm contained a relatively high amount of estrogens (112 +/- 15 pg/10(9) sperm). These studies revealed marked differences in steroid profiles of fluids entering and leaving the epididymis and of infertile testicular and fertile cauda epididymal sperm.

Androstane-3,17-diol↗

PubMed1979

Endocrine features of an adrenal-like tumor of the ovary.

Detailed in vivo endocrine studies of a virilizing adrenal-like tumor of the ovary are reported. A nonspecific steroidogenic baseline profile was observed in the face of clearcut histological adrenal-like features. Dynamic testing disclosed incomplete dexamethasone-related steroidogenic suppression suggestive of partial tumoral autonomy. At the same time, the observation of sizable dexamethasone-related steroidogenic decrements, unaccounted for by normal adrenal contribution, may be interpreted to suggest a direct, pharmacological, inhibitory effect of dexamethasone on tumoral and/or ovarian stromal steroidogenesis. These observations confirm the limited role of baseline steroid profiling and dynamic testing in the preoperative localization of androgen-secreting tumors. Reversible dysfunction of hypothalamic gonadotropic feedback mechanisms was suggested by combined single dose LRH-clomiphene testing. Complete resolution followed tumor removal.

17-Hydroxycorticosteroids↗

PubMed1990

Effects of DHA-S on placental 3 beta-hydroxysteroid dehydrogenase activity, progesterone and 20 alpha-dihydroprogesterone concentrations in placenta and serum.

To study the effects of dehydroepiandrosterone sulfate (DHA-S) on placental steroid metabolism and maternal steroidal profiles at term, the following in vivo and in vitro experiments were performed. Two hundred mg of DHA-S was given to five pregnant women 30 minutes prior to delivery. After delivery, the placenta was collected and 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) and sulfatase activity was determined by measuring the rate of conversion of pregnenolone to progesterone and DHA-S to DHA. The amount of C21-delta 4-steroid in the placental tissue was measured by gas chromatography mass spectrometry (GC-MS) and compared with the control groups. The maternal serum concentration of several steroids was also measured by GC-MS before and after the administration of DHA-S. 3 beta-HSD activity in the placentae from the mothers who received DHA-S before delivery was significantly lower than in the controls. On the other hand, no significant change was observed in the activity of sulfatase. The serum concentration of progesterone (P) and 20 alpha-dihydro-P (20-P) before DHA-S loading decreased following the administration whereas estradiol (E), DHA, and androstenedione (A) levels increased. To study the direct effect of DHA-S and its related steroids on placental 3 beta-HSD activity, placental tissue samples were incubated with pregnenolone in vitro. Several other steroids were added simultaneously into the medium. It was observed that placental 3 beta-HSD activity was directly inhibited by DHA-S. These results indicate that DHA-S inhibits 3 beta-HSD activity in the placenta and subsequently causes a reduction in P and 20-P.

20-alpha-Dihydroprogesterone↗

PubMed2005

Urinary steroid measurements in some endocrine and psychiatric diseases.

In 1990, the worldwide accepted Shackleton method, which provides a possibility of determining the steroid metabolites from urine, was adopted in our laboratory. The procedure is very useful in the diagnosis of different endocrine diseases and in the recognition of dysfunction or absence of enzymes with an important role in steroid metabolism, and it gives possibility to control the treatment in patients with these diseases. Besides the proximate clinical application, the method gives a convenient tool to study the steroid background of these disorders, helping us understand the mechanism of their development. In the last few years, we have examined the steroid profile of patients with hair (androgen alopecia /AA/, effluvium /E/), psychiatric problems (major depression /MD/, eating disorders /EDS/, especially anorexia nervosa and bulimia) and osteoporosis (OP). In all of the examined hair loss diseases, the levels of main androgen metabolites were increased, and elevated 5alpha-reductase activity were found. We could observe the alteration of the activity of 11beta-hydroxysteroid dehydrogenase (11beta-HSD) enzyme and marked gender differences in the changes of the steroid metabolism in patients with major depression (MD). In women with OP, the significantly decreased level of certain metabolites points to the role of testosterone, androstenedione and DHEA in postmenopausal bone loss in women. Our experiences contribute to the knowledge of the nature and steroid background of some endocrine and psychiatric diseases.

Adult↗

PubMed1986

Alterations of heme, cytochrome P-450, and steroid metabolism by mercury in rat adrenal.

The treatment of male rats with Hg2+ resulted in significant alterations in heme and hemoprotein metabolism in the adrenal gland which, in turn, were reflected in abnormal steroidogenic activities and steroid output. Twenty-four hours after the administration of 30 mumol of HgCl2/kg (sc) the mitochondrial heme and cytochrome P-450 concentrations increased by approximately 50%. Also, Hg2+ treatment stimulated a porphyrinogenic response which included an 11-fold increase in the activity of delta-aminolevulinate synthetase. The increase in mitochondrial cytochrome P-450 content was reflected in elevated steroid 11 beta-hydroxylase and cholesterol side-chain cleavage activities. In contrast, Hg2+ treatment resulted in decreased concentrations of microsomal cytochrome P-450 (-75%) and heme (-45%). Similarly, the reduction in the microsomal cytochrome P-450 content was accompanied by reduced steroid 21 alpha-hydroxylase and benzo[alpha]pyrene hydroxylase activities. The mechanisms responsible for the loss of the microsomal cytochrome P-450 content appeared to involve a selective impairment of formation of the holocytochrome as well as an enhanced rate of heme degradation. This suggestion is made on the basis of findings that (a) the decrease in the microsomal cytochrome P-450 content was accompanied by a sevenfold increase in the activity of adrenal heme oxygenase, (b) no decrease in apocytochrome P-450 could be detected in sodium dodecyl sulfate-gel electrophoresis of the solubilized microsomal fractions stained for heme, and (c) the concentration of adrenal microsomal cytochrome b5 was significantly increased in the Hg2+-treated animals. It is suggested that Hg2+ directly caused a defect in adrenal steroid biosynthesis by inhibiting the activity of 21 alpha-hydroxylase. The apparent physiological consequences of this effect included lowered plasma levels of corticosterone and elevated concentrations of progesterone and dehydroepiandrosterone. This abnormal plasma steroid profile is indicative of a 21 alpha-hydroxylase impairment.

5-Aminolevulinate Synthetase↗

PubMed1982

The diagnosis of 21-hydroxylase deficiency in a prematurely born infant on the basis of the urinary steroid excretion pattern.

The urine of a 6-day-old prematurely born female infant (birth weight 1060 g) suspected of having a 21-OH-deficiency showed no steroid abnormalities on capillary GLC analysis. Using GC-MS tetrahydrocortisone (THE) and also 3 alpha, 17 alpha-dihydroxy-5 beta-pregnane-20-one (17-OH-Polone) were absent, but two androstanetriolone peaks were observed. In the urine collected on day 9 THE was absent, but a large amount of 3 alpha, 11 beta-dihydroxy-5-alpha-androstane-17-one (11-HA) was found by GC-MS to be contaminated by a small amount of 17-OH-Polone. The next urine specimen collected on the 22nd day while the child received cortisol therapeutically showed the characteristic steroid profile for the diagnosis 21-OH deficiency, large peaks of 17-OH-Polone, pregnanetriol (P3) and 11-keto-pregnanetriol (11-keto-P3). Over the next few weeks two other compounds were found to have been excreted in relatively large amounts, 3 xi, 16 xi, 17 xi, 20 xi-pregnanetetrol (16-OH-P3) and surprisingly also a 21-hydroxylated compound, namely 3 xi, 20 alpha, 21-trihydroxy-5-pregnene. These same two compounds were also found in the urine of another infant with suspected 21-OH deficiency. The urinary steroid excretion patterns characteristic for 21-OH deficiency are dependent on the maturity and age of the infant. In the prematurely born infant androstanetriolones appear in the urine before 17-OH-Polone. The occurrence of these different steroid excretion patterns is tentatively explained.

Adrenal Hyperplasia, Congenital↗

PubMed2001

[Plasma insulin, IGF-I and breast cancer].

Several recent epidemiological studies have shown an increase in breast cancer risk among women who have elevated plasma levels of testosterone, reduced levels of sex hormone-binding globulin (SHBG), and hence elevated levels of bioavailable androgens and estrogens not bound to SHBG. This endocrine profile is generally associated with obesity and chronic hyperinsulinemia, of which it is most likely a result. Lack of physical activity, obesity, and a diet rich in rapidly digestible carbohydrates and poor in fibre favour the development of insulin resistance and hyperinsulinemia. The elevated insulin levels, in turn are related to decreases in plasma and tissue levels of IGFBP-1 and IGFBP-2 (insulin-like growth factor-binding proteins), and this may increase the availability of insulin-like growth factor-I (IGF-I) to its receptors. Like insulin, IGF-I also inhibits the hepatic synthesis of SHBG, whereas both hormones stimulate the ovarian synthesis of sex steroids. Moreover, insulin and IGF-I can both enhance the development of breast tumours, through their cognate receptors within the mammary tissue. Taken together, these observations lead to the hypothesis that breast cancer risk may be increased in women with elevated plasma insulin levels, and/or with elevated levels of bioactive IGF-I. Hyperinsulinemia and an increased IGF-I bioactivity could thus be an important physiological link between a western lifestyle, overnutrition, a hyperandrogenic sex steroid profile, and increased breast cancer risk. Prospective cohort studies will be needed to test this hypothesis, and to study in greater detail the possible relationships of breast cancer risk with plasma levels of IGF-I and IGFBPs. Confirmation of a relationship of breast cancer risk with plasma insulin levels, on the one hand, or with total plasma IGF-I, on the other hand, could open up new perspectives for breast cancer prevention, either by changes in dietary intake patterns and physical activity, or by the use of certain chemopreventive drugs.

Breast Neoplasms↗

PubMed1991

Lack of effect of perindopril on plasma and adrenal corticosteroids in the guinea pig during the estrous cycle and under contraceptive treatment.

We studied changes in cortisol, aldosterone, progesterone, estrogens and cholesterol in cyclic female guinea-pigs and in animals under contraceptive, treated or not with an inhibitor of angiotensin converting enzyme (ACE): perindopril. Perindopril decreased ACE by 80% without affecting steroid profiles. Peak value for plasma progesterone occurred at meta-estrus and diestrus. It disappeared under contraceptive treatment. The very low levels of estrogens in the female guinea pig remained unchanged in all cases. Plasma cortisol concentrations were higher at pro-estrus and estrus whereas plasma aldosterone concentrations remained constant during the estrous cycle and under contraceptive treatment. Furthermore, aldosterone did not change under perindopril treatment despite the decrease of the activity of ACE. The contraceptive treatment decreased plasma cholesterol levels. Under perindopril treatment, this drop was amplified. No change was detected in adrenal steroid concentrations, except for progesterone which decreased under contraceptive treatment.

Adrenal Cortex Hormones↗

PubMed2004

Adrenal steroid hormones and metaphyseal bone in children.

BACKGROUND/OBJECTIVES: The responses of metaphyseal bone tissue to physiological variations of endogenous adrenal steroid hormones during childhood are unclear. Therefore, we studied potential hormonal influences in children before the appearance of pubic hair (onset of pubarche). METHODS: Excretions of major glucocorticoid metabolites (C21), cortisol, sum of adrenarchal dehydroepiandrosterone and its immediate 16-hydroxylated metabolites (DHEA&M), and 5-androstene-3beta,17beta-diol (hermaphrodiol) were analyzed in a cross-sectional study in 24-hour urine samples of 109 healthy boys and girls, aged 6-13 years, using steroid profiling by gas chromatography-mass spectrometry. Total and trabecular volumetric bone mineral densities, bone mineral content (BMC) and bone strength strain index were determined with peripheral quantitative computed tomography at the distal forearm. RESULTS: In multiple regression analyses significant associations with the metaphyseal radius were seen for grip force, age, or BMI depending on gender and bone variable analyzed. DHEA&M did not contribute to the explanation of the variance of any bone variable. However, hermaphrodiol positively explained a significant part of variation of bone mineral densities, and BMC (p < 0.01) in girls. Significantly negative associations with all bone variables were seen in boys for cortisol. CONCLUSIONS: The steroid hormones, cortisol and hermaphrodiol, in their physiological ranges, but not the adrenarche marker DHEA&M, appear to associate with metaphyseal bone in a sex-dependent manner during childhood.

Adolescent↗

PubMed2004

Effects of ileo-rectal anastomosis on cholesterol metabolism in pigs fed either casein or extruded soya beans.

The importance of legume proteins in cholesterol metabolism has been recognised, but the hindgut contribution is still unclear. The present work was undertaken to address the role of the caecum-colon in cholesterol metabolism in intact (I) and ileo-rectal anastomosed (IRA) pigs fed with casein or extruded soyabean (ES) diets. Four groups of six growing pigs were assigned to the treatments (casein-I, casein-IRA, ES-I, ES-IRA) for 3 weeks. Plasma total cholesterol, LDL- and HDL-cholesterol were not modified by surgery or diet. In the liver, the ES diet significantly depressed non-esterified, esterified and total cholesterol. The treatments did not affect hepatic 3-hydroxy-3-methylglutaryl CoA reductase, cholesterol 7alpha-hydroxylase or sterol 27-hydroxylase activities. In the gallbladder bile of ES-fed pigs, total cholesterol was depressed while total bile acid concentration was increased. IRA and the ES diet markedly decreased the biliary bile acid microbial metabolites (namely hyodeoxycholic acid) and increased the primary bile acids (mainly hyocholic acid). The concentration of bile hydrophobic acids was decreased only by the ES diet. Faecal neutral sterol output was increased in ES-fed pigs, but the bile acid and the sum of neutral and acidic steroid outputs were not. Microbial transformation of neutral and acidic steroids was markedly reduced by IRA, especially in the ES-fed pigs. Thus, surgery and ES modulated the steroid profile but the caecum-colon did not seem to play a crucial role in determining cholesterolaemia in pigs.

Anastomosis, Surgical↗

PubMed1999

Plasma adrenal, gonadal, and conjugated steroids following long-term exercise-induced negative energy balance in identical twins.

There are few reports of the change in sex hormone levels accompanying a weight change in men, although an excessive decline in testosterone (TESTO) has been described as an associate of stress-induced weight loss. Plasma levels of cortisol, TESTO, dihydrotestosterone (DHT), dehydroepiandrosterone sulfate (DHEA-S), androsterone glucuronide (ADT-G), and androstane-3alpha, 17beta-diol glucuronide (3alphaDIOL-G) were measured in seven pairs of sedentary male monozygotic twins (age, 21.0 +/- 0.8 years; body mass index [BMI], 26.2 +/- 5.5 kg/m2) before and after 93 days of standardized submaximal (50% to 55% maximum oxygen consumption) cycle-ergometer exercise. A total energy deficit of 244 +/- 9.7 MJ induced significant changes (P < .0001) in body weight ([BW] -5.0 +/- 2.2 kg) and body fatness measures. Plasma TESTO and DHEA-S increased and 3alphaDIOL-G decreased. The increase in TESTO was a significant inverse correlate of loss in all measures of body fat, particularly central adiposity (r = -.58 to -.86, P < .001, fat loss-adjusted). Lower postexercise levels of 3alphaDIOL-G correlated positively with decreased body composition measures (r = .65 to .68, P < .01). The increase in plasma TESTO accompanying the loss of abdominal visceral fat (AVF) was greater in men with lower fasting insulin levels (P < .0001). The baseline within-twin-pair resemblance in TESTO and 3alphaDIOL-G (intraclass correlation coefficients [ICC] = .83 and .78, respectively, P < .01) was lost with intervention. Cortisol, DHEA-S, and ADT-G developed within-twin-pair similarity (ICC adjusted for fat loss: cortisol, .72; ADT-G, .62, P < .05; DHEA-S, .85, P < .002). We conclude that a steroid profile characterized by high TESTO and low androgen metabolite levels accompanied the changes in body composition and body fat distribution generated by the exercise-induced negative energy balance. Furthermore, these changes were characterized by a significant resemblance within identical-twin pairs.

Adult↗

PubMed2006

Gonadal steroid modulation of stress-induced hypothalamo-pituitary-adrenal activity and anxiety behavior: role of central oxytocin.

Intracerebroventricular administration of oxytocin reduces anxiety behavior and hypothalamo-pituitary-adrenal (HPA) responses to stress in female rats. Similar changes are seen in late-pregnant rats, and oxytocin-sensitive pathways may mediate these effects. This study investigated anxiety behavior and stress responses using a gonadal steroid model of late pregnancy, which is known to increase endogenous oxytocin expression. Compared with continuous progesterone treatment, 3-d withdrawal of progesterone after 11-d treatment of ovariectomized rats with estradiol and progesterone resulted in increased binding of the oxytocin receptor ligand [(125)I]d(CH(2))(5)[Tyr(Me)(2),Thr(4),Tyr-NH(2)(9)]ornithine vasotocin in selective forebrain regions, including the ventrolateral septum and ventromedial hypothalamus. Behavior in the elevated plus-maze indicated that progesterone withdrawal had an anxiolytic effect, and this was associated with lower levels of c-fos mRNA expression in the ventral hippocampus, an area previously shown to be sensitive to oxytocin. In other groups of animals, the plasma corticosterone response to a psychological stress (10 min of 114 dB white noise) was significantly attenuated by this steroid manipulation. Furthermore, simultaneous infusion of the selective oxytocin receptor antagonist desGlyNH(2), d(CH(2))(5)[Tyr(Me)(2),Thr(4)]OVT during the period of progesterone withdrawal reversed this attenuation of noise-induced HPA activation, indicating a role for endogenous oxytocin in this effect. Thus, mimicking the steroid profile of late pregnancy leads to a reduction in anxiety behavior and attenuates HPA activity induced by mild stress. These effects appear to be mediated through the involvement of central oxytocin neurotransmission.

Adrenal Glands↗

PubMed2005

Influence of the Ginkgo extract EGb 761 on rat liver cytochrome P450 and steroid metabolism and excretion in rats and man.

Extracts from leaves of Ginkgo biloba L. are among the most used herbal medicinal products worldwide. Based on in-vitro tests and studies in rats, concern has been expressed that intake of Ginkgo extracts may affect hepatic metabolism of xenobiotics and cause drug interactions, although no evidence for modulation of cytochrome P450 (CYP450) enzyme activity was obtained in human trials. Because of these contradictory findings, we investigated the effects of the standardised extract EGb 761 on hepatic CYP450 in rats. EGb 761 (100 mg kg-1 daily, p.o., for 4 days) strongly increased liver CYP450 content and altered the ex-vivo biotransformation of androstendione, as well as metabolism of endogenous steroids. However, in human subjects no effect on the urinary steroid profile was observed after intake of EGb 761 for 28 days (240 mg daily). These results indicate that the effects of EGb 761 on drug metabolising enzymes are specific for rats and may not be extrapolated to man.

Administration, Oral↗

PubMed1996

Evidence for independent modulation of human 11-HSD and 5 alpha/5 beta reductase activities.

The increased ratio of 5 alpha to 5 beta reduced steroids associated with apparent mineralocorticoid excess (AME) may be a necessary consequence of altered 11 beta-hydroxysteroid dehydrogenase (11-HSD) activity. In order to test this hypothesis we have compared changes in 11-HSD activity and 5 alpha/5 beta reduction in a variety of clinical and experimental conditions. The ratio of 11-oxo/11 beta-hydroxy metabolites of cortisol (11-oxo/11-OH FM) was used as an index of 11-HSD activity and the ratio of allotetrahydrocortisol/ tetrahydrocortisol (allo THF/THF) was used as an index of 5 alpha/5 beta reduction. Ratios were derived from 24 hour urinary steroid profiles measured by high resolution gas chromatography. The clinical conditions studied were Cushing's Syndrome, Major Depression and hirsutism. In each study, the patient group were compared with age-matched healthy controls. For the experimental conditions, subjects treated with either hydrocortisone, dexamethasone, metyrapone or finasteride acted as their own controls. No consistent relationship was found between changes in the ratios of 11-oxo/11-OH FM and allo THF/THF. We conclude that there is no evidence of consistent metabolic interaction between 11-HSD and 5 alpha/5 beta reductase activities under a wide range of conditions. Furthermore, the patterns of metabolic changes seen in these conditions are no less characteristic, although more subtle, than the well-documented metabolic changes seen in inborn errors of steroid metabolism.

11-beta-Hydroxysteroid Dehydrogenases↗

PubMed1997

Male gonadal denervation by guanethidine at pre-puberty: different doses, different results. The intervention of the pineal deafferentation.

Since gonadal denervation and pineal deafferentation by cervical superior ganglionectomy affect sexual development, this study was performed to evaluate testicular steroidogenesis, spermatogenesis and the cervical superior ganglion (CSG) histology in rats treated with guanethidine (GD). The treatment was performed by GD s.c. injections for 3 weeks, from the 21st day of age to the 41st day of age (pre-puberty), when the animals were sacrificed. Different doses were used: group A = 10 mg/kg/day, group B = 50 mg/kg/day and saline (control group). Testicular denervation was confirmed by HPLC for catecholamines in testicular tissue. Testicular concentrations (TC) of progesterone (P4) and testosterone (T) were measured by RIA. Significantly higher TC of P4 and lower TC of T were observed only in group A in comparison with group B and the control group. No alteration of sperm production was observed in either treated group. Histological analysis of CSG showed only few neuronal alterations in group A rats, while in group B the nervous cells were practically destroyed. This suggests that 10 mg/kg/day GD treatment probably produces a specific blockade of 17 alpha-hydroxylase/17,20 desmolase at pre-puberty leading to a decrease of the androgen production. However, in the 50 mg/kg/day group no differences were observed concerning the steroid profiles, this result being attributed to the extensive damage to the CSG observed only in group B. The CSG destruction causes deafferentation of the pineal gland producing abolishment of the inhibition of the 17 alpha-hydroxylase/17,20 desmolase promoted by melatonin or by an out of phase production of androgen.

Animals↗

PubMed1985

Changes in plasma steroid and thyroid hormones and insulin during final maturation and spawning of the sea lamprey, Petromyzon marinus.

Circulating levels of plasma estradiol-17 beta, androgens, thyroxine, triiodothyronine, immunoreactive insulin, plasma fatty acids, and protein were measured at interval during the period of final gonadal maturation, prior to spawning of male and female sea lampreys. Plasma estradiol levels fluctuated significantly and generally covaried in males and females through time. In females, possibly in relation to environmental changes, mean plasma estradiol levels peaked four times during the final spawning period but decreased sharply at the time of ovulation. In males, mean plasma estradiol peaked seven times during the final prespawning period and, in contrast to females, peaked significantly at the time of final spermiation. Plasma androgens were extremely low and covaried in males and females through time. Like plasma steroid profiles, there were coordinated changes in plasma triiodothyronine and thyroxine levels in males and females through the prespawning season. There was a slight increase in plasma insulin during the terminal maturation of the lampreys. However, at ovulation, the insulin levels abruptly decreased in females, whereas in males they remained unchanged. Plasma protein and fatty acid levels gradually decreased until ovulation/spermiation. At ovulation plasma fatty acid levels increased.

Androgens↗

PubMed2004

CYP11B2-CYP11B1 haplotypes associated with decreased 11 beta-hydroxylase activity.

Reduced adrenal 11 beta-hydroxylation has been associated with an aldosterone synthase (CYP11B2) polymorphism. The 11 beta-hydroxylase gene (CYP11B1) lies close to CYP11B2. We hypothesize that a molecular variant in CYP11B2 is in linkage disequilibrium (LD) with a key quantitative trait in CYP11B1 determining this phenotype. Polymorphisms and inferred haplotypes at CYP11B loci were studied in two independent populations from Europe (n = 100) and South America (n = 99). The latter underwent detailed hormonal studies. LD was estimated by alternative Bayesian methods for inferring the extent of LD when haplotypes at different loci are inferred. Population differences in single nucleotide polymorphisms were modest, indicating the stability of both genes across populations. Using five of nine potentially informative loci at CYP11B sites with allele frequency greater than 0.1, two major contrasting haplotypes, CwtCG and TconvGTA, were found. In both populations the CwtCG haplotype accounted for 44% and the TconvGTA for 32% of subjects. Haplotype distribution did not differ between Europeans and South Americans (chi(2) = 2.81; P = 0.09). In vivo 11 beta-hydroxylase activity, estimated from urinary steroid profiling, was lower in subjects with an increased aldosterone to renin ratio or with the TconvGTA haplotype. These findings indicate that genotypes at the CYP11B locus are in strong LD and that identified haplotypes predict 11 beta-hydroxylase activity.

Base Sequence↗