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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Steroid concentrations in plasma and follicular tissues (theca plus granulosa layers) were determined by radioimmunoassay in the aplacental viviparous ray, Torpedo marmorata, during various stages of the reproductive cycle. Steroids in the uterine fluid of pregnant animals and in preovulatory atretic follicles were also measured. In the follicular tissue of cyclic animals, levels of progesterone were always lower than those of estradiol-17 beta and androgens (testosterone plus 5 alpha-dihydrotestosterone). Estradiol-17 beta and androgen levels increased as the animals approached the ultimate maturational stage before ovulation. Androgens were not detectable in plasma, while estradiol-17 beta increased dramatically before ovulation. In pregnant animals, only small ovarian follicles (less than 5 mm in diameter) were observed, and these had hormone concentrations that were similar to those of the small follicles of cyclic animals. Progesterone was the only steroid detected in the uterine fluid of pregnant animals. In completely sclerotic atretic follicles of pregnant animals, steroids were not detected. Progesterone was the main hormone in atretic follicles undergoing yolk resorption. This suggests that the latter may contribute to the elevated plasma progesterone concentrations of pregnant animals.
Gen Comp Endocrinol 1992 Feb
PMID:Plasma and follicular tissue steroid levels in the elasmobranch fish, Torpedo marmorata. 160 Dec 64

Gas chromatography/mass spectrometry with selected ion monitoring has been employed to examine extracts from the ovary, eggs, and haemolymph of the marine prawn, Nephrops norvegicus, to demonstrate the presence of steroids. Both free and conjugated steroids were isolated by solvent partitioning and chromatography (lipophilic Sephadex, reversed-phase Sep Pak, and normal phase medium-pressure liquid chromatography) and steroidal conjugates were cleaved enzymatically. Steroids were determined as their methyloxime derivatives, trimethylsilyl (TMS) ethers or methyloxime-TMS ethers. All assignments were based on the detection of characteristic ions and cochromatography with the authentic steroid derivatives. 5 alpha-Dihydrotestosterone, testosterone, pregnenolone, and 20 alpha-hydroxypregn-4-en-3-one were detected in unconjugated form in the ovary. The eggs and haemolymph were found to contain unconjugated 17 beta-estradiol. Conjugated 5 alpha-dihydrotestosterone was detected in both the ovary and haemolymph, but no conjugated steroids were found in the eggs.
Gen Comp Endocrinol 1989 May
PMID:Detection of unconjugated and conjugated steroids in the ovary, eggs, and haemolymph of the decapod crustacean Nephrops norvegicus. 271 24

All the steroids produced by Atlantic croaker ovaries during final oocyte maturation (FOM) were assayed for their ability to induce germinal vesicle breakdown (GVBD) of croaker oocytes in vitro. Ovarian tissue in the process of FOM was removed from Atlantic croaker (Micropogonias undulatus) and incubated with human chorionic gonadotropin (hCG) and pregnenolone in tissue culture medium for 8 hr. Steroids were extracted from the medium and fractionated by HPLC and TLC. Fractions were bioassayed for their potency to induce GVBD of Atlantic croaker oocytes in vitro. 17 alpha, 20 beta,21-Trihydroxy-4-pregnen-3-one (20 beta-dihydro-11-deoxycortisol, 20 beta-S) was identified as the predominant steroid product and the major maturation-inducing steroid produced by the ovary of Atlantic croaker in vitro. A small amount of another steroid with equal potency to induce GVBD was tentatively identified as 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-P4); however, over ten times more 20 beta-S than 17 alpha,20 beta-P4 accumulated in the incubation medium. Trace amounts of testosterone and estradiol-17 beta were also isolated. Ovarian tissue incubated under more physiological conditions, without the addition of excess pregnenolone, failed to produce 17 alpha,20 beta-P4. These results provide further evidence that 20 beta-S is a major maturation-inducing steroid in Atlantic croaker.
Gen Comp Endocrinol 1989 Sep
PMID:Isolation of a novel maturation-inducing steroid produced in vitro by ovaries of Atlantic croaker. 279 25

Mixed cell preparations (theca plus granulosa) prepared from the hierarchy of follicles of quails ovaries were incubated under defined conditions with or without the addition of ovine luteinizing hormone (oLH), ovine follicle stimulating hormone (oFSH), theophylline, cycloheximide, or dibutyryl cyclic adenine monophosphate (db cAMP); or in the presence of androstenedione or testosterone as aromatizable substrate. Steroids secreted into the medium during the 4-hr incubation period were assayed by radioimmunoassay. Cells from the largest follicles (F1) secreted predominantly progesterone, were stimulated by LH and db cAMP, and the response was potentiated by theophylline, but FSH had no stimulatory effect. The F1 cells showed increasing basal and LH-stimulated responses between 18 and 12 hr before the next expected oviposition. Cells from the smaller follicles (F3 and F4) secreted predominantly estrogens, and were stimulated by FSH but not by db cAMP and only to a small extent by theophylline. Addition of androstenedione (10(-7) M) or testosterone (10(-7) M) enhanced estrogen secretion, which was further raised by the simultaneous addition of FSH. These results confirm previous reports on the sites of steroid secretion within quail follicles and suggest that while the action of LH on the cells from F1 follicles may be mediated in part through the adenylate cyclase system, the action of FSH on the smaller follicles may be substantially independent of cAMP.
Gen Comp Endocrinol 1988 Nov
PMID:Steroid secretion by ovarian cells of the Japanese quail (Coturnix coturnix japonica). 284 45

The effect of alterations of the steroid nucleus on its potency to induce germinal vesicle breakdown (GVBD) of Atlantic croaker oocytes in vitro was investigated. The addition of 17 alpha-, 20 beta-, or 21-hydroxyl groups to the progesterone steroid nucleus enhanced steroid potency to induce GVBD. Whereas the 20 beta-hydroxyl group on the side chain was the most potent single alteration of the progesterone nucleus, the 17 alpha-hydroxyl group seemed to be vital for establishing the proper steric orientation of the side chain. The most potent steroids to induce GVBD contained either the 17 alpha,20 beta-dihydroxy or the 17 alpha,20 beta,21-trihydroxy configuration. Steroids of the 3-keto-delta 4 and the 3 beta-hydroxy-delta 5 configuration had similar potency. In addition, the 3 beta-hydroxysteroid dehydrogenase inhibitor, cyanoketone, did not affect human chorionic gonadotropin-induced GVBD. However, other alterations of the A and B rings of the steroid nucleus resulted in diminished potency (3 alpha-hydroxy, 5 alpha, and 5 beta configurations). Addition of hydroxyl groups at the 11 beta, 16 alpha, or 20 alpha positions resulted in steroids with reduced potency. The low potency of steroids lacking the side chain (estrogens and androgens) and steroids with the side chain in the 17 alpha position (progestin analogs) is further evidence that the side chain configuration is important for biological activity. Human chorionic gonadotropin and other gonadotropin preparations induced GVBD of croaker oocytes in vitro which indicates that the maturational steroid is of ovarian origin. The finding that 17 alpha,20 beta,21-trihydroxy-4-pregnen-3-one (20 beta-S), a major steroid product of croaker oocytes during final oocyte maturation, is a potent inducer of GVBD suggests that it may function as a maturation-inducing steroid in this species.
Gen Comp Endocrinol 1988 Aug
PMID:Structure-activity relationships of steroids in inducing germinal vesicle breakdown of Atlantic croaker oocytes in vitro. 320 78

Rainbow trout, Salmo gairdneri, oocytes were used in an in vitro bioassay to test for the potency of C21 steroids in inducing final maturation. A wide range of steroids was used and most of the assays were replicated at least 3 times and up to 10 times with the most effective steroids. 17 alpha,20 beta-Dihydroxy-4-pregnen-3-one (17,20 beta-P), which has been identified as the natural maturation-inducing steroid in Salmoniformes, was used as the reference steroid. Four steroids, 17 alpha,20 beta,21-trihydroxy-4-pregnen-3-one; 3 alpha,17 alpha,20 beta-trihydroxy-5 alpha-pregnane; 3 beta,17 alpha,20 beta-trihydroxy-5 alpha-pregnane; and 3 alpha,17 alpha,20 beta,21-tetrahydroxy-5 alpha-pregnane were found to be equipotent with 17,20 beta-P. Analysis of the structure-activity relationships indicated that, for maximum biological activity, steroids must have a planar nucleus (as in delta 4 and 5 alpha-reduced steroids), a hydroxyl or keto group at position 3, and hydroxyl groups at positions 17 and 20 beta. Steroids with delta 5 or 5 beta-reduced conformations and/or hydroxyl or keto groups at position 11 had a much reduced biological activity.
Gen Comp Endocrinol 1988 Aug
PMID:Structure-activity relationships of C21 steroids in an in vitro oocyte maturation bioassay in rainbow trout, Salmo gairdneri. 320 79

In vitro steroidogenesis of ovarian follicles incubated with radioactive precursors or a Fundulus heteroclitus pituitary extract (FPE) was investigated. Steroids were extracted from both the medium and follicular tissue and fractionated by liquid or thin-layer chromatography. A similar pattern of steroid metabolites was obtained with either [14C]pregnenolone or [14C]progesterone as exogenous precursor. Several metabolites comigrated with known reference steroids and thus were tentatively identified. Some have been previously reported to induce germinal vesicle breakdown (GVBD) in this and other species, particularly 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (DHP). [3H]DHP added to intact follicles or denuded oocytes was also extensively metabolized. All the DHP metabolites produced by the intact follicle were tested for biological activity. Three of the metabolites were almost as effective inducers of GVBD as DHP itself, and two were tentatively identified as 5 alpha-pregnan-3 alpha,17 alpha,20 beta-triol and 5 alpha-pregnan-3 beta,17 alpha,20 beta-triol. However, DHP was the most potent and the quickest inducer of GVBD, indicating that its maturational action is not due to metabolic conversion to a more active form. In addition, we found two very active fractions after HPLC analysis of steroid extracts from FPE-stimulated follicles: one that corresponded to and was further identified (mass spectroscopy) as DHP and a second tentatively identified as the DHP metabolite 5 alpha-pregnan-3 beta,17 alpha,20 beta-triol. This study provides strong evidence that DHP plays the major role as a maturation inducing-steroid in F. heteroclitus, even though DHP is not the only active steroid produced by maturing follicles.
Gen Comp Endocrinol 1993 Oct
PMID:Steroidogenesis in Fundulus heteroclitus V.: purification, characterization, and metabolism of 17 alpha,20 beta-dihydroxy-4-pregnen-3-one by intact follicles and its role in oocyte maturation. 826 51

The leading explanation of temperature-dependent sex determination (TSD) in reptiles postulates that (1) ovarian differentiation is directed by estrogen and that (2) estrogen is synthesized in the developing gonad following induction of aromatase expression. However, the source of steroid substrate for aromatization has not yet been identified. In addition, sex ratios vary as a function of clutch, but such biases are as yet unexplained. To address these issues, we measured estradiol, testosterone, and androstenedione in yolks of the American alligator (Alligator mississippiensis) before, during, and after the period of gonadal differentiation in this TSD species. Eggs were collected from a wild population in Louisiana and were incubated at male- and female-determining constant temperatures in the lab, as well as at intermediate temperatures that produced both sexes. Steroids were assayed in yolk extracts after celite column chromatography. All three steroids were found to be in the range of nanograms/gram of yolk at stage 16. Androstenedione was the predominant steroid, 2- to 3-fold higher in concentration than estradiol and 15- to 20-fold higher than testosterone. The levels of these steroids declined (5- to 30-fold) between stages 16 and 25, most markedly between stages 21 and 23, regardless of incubation temperature. The chronology of this sharp decline in steroid levels in our study coincides with the timing of gonadal differentiation in this species, between stages 21 to 23 based on previous reports. Estradiol levels in yolks differed by 3-fold in some clutches relative to others, whereas, no clutch differences were apparent for either androstenedione or testosterone. These data demonstrate that alligator yolk contains high concentrations of two steroid substrates utilized for estrogen synthesis, as well as significant quantities of estradiol itself. We hypothesize that estradiol levels in yolk provide a steroid background, variable among and within clutches, on which gonadal development is initiated and proceeds. As a consequence, we suggest that yolk provides an epigenetic maternal contribution that modulates the effect of incubation temperature on hatchling sex.
Gen Comp Endocrinol 1997 Aug
PMID:Yolk steroids decline during sexual differentiation in the alligator. 924 27

Plasma concentrations of steroids during the periovulatory period were measured in female common wolffish reared at three different temperatures. Steroids were quantified by radioimmunoassay (RIA). Two "broad-spectrum specificity" RIAs-one which detects C21-steroids with a 17,20beta-dihydroxyl configuration (17,20beta-steroids) and the other which detects C21-steroids with a 5beta-reduced, 3alpha-hydroxyl configuration (5beta,3alpha-steroids)-picked up very large amounts of cross-reacting material (1.7 microg ml(-1) in one fish) in the sulfate fraction of plasma from ovulating females. Reverse-phase high-performance liquid chromatography and thin-layer chromatography revealed two major steroids: 5beta-pregnane-3alpha,17,20beta-triol (80%) and 5beta-pregnane-3beta,17,20beta-triol (20%). The sulfated forms of these steroids were elevated 4 to 6 days before and during ovulation, compared with those of females in vitellogenic and postspawning condition, in which concentrations were below 2.0 ng ml(-1). In the three groups of fish held at 4, 8, and 12 degrees C during vitellogenesis, but returned to 4 degrees C just prior to the spawning season, the mean concentrations of sulfated 17,20beta-steroids in ovulating females were 530, 635, and 325 ng ml(-1), respectively. The corresponding concentrations of free 17,20beta-dihydroxy-4-pregnen-3-one (17,20beta-P; the maturation-inducing steroid in many teleosts) were 0.88, 0.86, and 0.57 ng ml(-1), respectively. Only minute amounts of 17,20beta,21-P and its sulfated derivatives were detected. Significantly lower steroid concentrations in the 12 degrees C group indicate that steroid synthesis and/or metabolism during the periovulatory period are influenced by the temperature experienced during vitellogenesis. In male fish, plasma concentrations of both sulfated 17,20beta-steroids and free 17,20beta-P were low (< 2.0 ng ml(-1)) at all times.
Gen Comp Endocrinol 2000 Mar
PMID:Plasma-sulfated C21-steroids increase during the periovulatory period in female common wolffish and are influenced by temperature during vitellogenesis. 1076 57

Ovarian follicles and plasma were collected from two female white sturgeon, Acipenser transmontanus, injected with sturgeon pituitary homogenate followed 12h later with GnRHa to induce ovulation. The oocytes of one female underwent germinal vesicle breakdown (GVBD) but ovulation did not occur in response to hormonal stimulation (Female 1), while the oocytes of the other female underwent GVBD and ovulation (Female 2). Follicles collected 12h after the first injection to induce ovulation were incubated with radioinert pregnenolone (P5) or tritiated-P5 ([3H]P5) plus radioinert P5. Steroids were extracted from media and intact follicles, and the extracts were fractionated by high performance liquid chromatography (HPLC). Fractions from the incubation with radioinert precursor were used in a bioassay to determine the potency of the steroid products to induce GVBD. Plasma levels of testosterone (T), estradiol, and 17,20beta-dihydroxy-4-pregnen-3-one (17,20beta-P) were measured by radioimmunoassay during induced ovulation, and plasma collected at the time of ovulation (actual or expected) was analyzed by HPLC. A peak in plasma 17,20beta-P was detected at the time of the second injection to induce ovulation in Female 2 (the time at which follicles were collected for incubation with [3H]P5). The HPLC analysis revealed several progestins in the plasma of Female 2 at ovulation that were not present in Female 1 at the time of expected ovulation. A variety of C19 and C21 steroids were produced in vitro by ovarian follicles from both females. The "suggestive" identities of the major metabolites were 11-deoxycortisol, androstenedione, 17-hydroxyprogesterone (17OHP), and 17,20beta-P in Female 1 and cortisol, 17,20beta, 21-trihydroxyprogesterone (20beta-S), 11-deoxycortisol, T, 17OHP, and 17,20beta-P in Female 2. Several of the steroids were active in a GVBD bioassay, but the fractions that contained the steroid coeluting the authentic 11-deoxycortisol on the HPLC and 17,20beta-P (positively identified by gas chromatography-mass spectrometry) were found to be the most potent. The results from this study combined with the results of Webb et al. (2001b) suggest the potential roles of 11-deoxycortisol, 17,20beta-P, 20beta-S, and P4 as maturation-inducing steroids in sturgeon.
Gen Comp Endocrinol 2002 Oct 15
PMID:Ovarian steroidogenesis in white sturgeon (Acipenser transmontanus) during oocyte maturation and induced ovulation. 1240 93


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