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D E Kime

Publications and source records attributed to D E Kime.

At least 37 records · Page 2Linked to original sources
PubMed1992

In vitro biosynthesis of steroids, including 11-deoxycortisol and 5 alpha-pregnane-3 beta,7 alpha,17,20 beta-tetrol, by ovaries of the goldfish Carassius auratus during the stage of oocyte final maturation.

To examine the production of steroids with potential oocyte maturation-inducing or pheromonal activity in the goldfish (Carassius auratus) we have incubated mature ovaries of this species with 17-[3H]hydroxyprogesterone. The metabolites in the unconjugated, glucuronide, and sulfate fractions were identified by chromatography, microchemical reaction, and, in most cases, crystallization to constant specific activity. A major metabolite, present in all three fractions, was tentatively identified as 5 alpha-pregnane-3 beta,7 alpha,17,20 beta-tetrol. Although 17,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P) was found in only low yield (as a sulfate), the presence of the tetrol indicates that it is synthesized in high yield but very rapidly metabolized. The relative proportions of 17,20 alpha-dihydroxy-4-pregnen-3-one (17,20 alpha-P), 11-deoxycortisol (17,21-dihydroxy-4-pregnen-3,20-dione) and 17,20 beta,21-trihydroxy-4-pregnen-3-one (17,20 beta,21-P) varied significantly between incubations and may be affected by the maturational state of the ovary or the method used to stimulate oocyte maturation. Testosterone was present predominantly as its glucuronide. Significant production of glucuronides and sulfates was observed in all incubations. Twenty-five to 30% of the radioactivity remained associated with the tissue, but the distribution of activity between the metabolites did not differ greatly from that found in the medium. These results indicate that 11-deoxycortisol and its 20 beta-reduced derivative (17,20 beta,21-P) may be significant in spawning female goldfish.

17-alpha-Hydroxyprogesterone↗
PubMed1992

Steroid metabolism by ovarian follicles and extrafollicular tissue of the guppy (Poecilia reticulata) during oocyte growth and gestation.

In the viviparous guppy, fertilization and gestation are intrafollicular. Fully developed embryos are ovulated at the end of gestation just prior to parturition. The metabolism in vitro of various radiolabeled steroid precursors by isolated ovarian follicles at various stages of the reproductive cycle and extrafollicular (EF) tissue of the guppy was investigated. While estradiol-17 beta was one of the end products of metabolism in vitellogenic follicles, 17 alpha, 20 beta-P and several 5-reduced metabolites were synthesized by postvitellogenic follicles. The yield of 17 alpha, 20 beta-P, however, was much lower than some 5 beta-reduced metabolites synthesized by postvitellogenic follicles. Gestation stage follicles rapidly converted the precursors into 5-reduced and polar 7-hydroxylated steroids, and their glucuronides. Although postpartum follicles showed very poor potential for steroid metabolism, they synthesized estradiol-17 beta from testosterone. These results demonstrate distinct changes occurring in the steroidogenic potential of the follicles during the reproductive cycle. Unlike in other viviparous vertebrates, no particular steroid seems to be involved in maintaining gestation in the guppy; all the steroid precursors are converted into highly polar metabolites and their conjugates during gestation, thereby facilitating their excretion. The EF ovarian tissue also synthesized 7-hydroxylated steroids and their glucuronides, providing evidence for the first time that the teleost ovarian EF tissue plays a role in steroidogenesis. The possible physiological significance of the synthesis of the novel polar steroids by the follicles and the EF tissue is discussed.

17-alpha-Hydroxyprogesterone↗
PubMed1992

Steroid metabolism in teleost gonads: purification and identification of metabolites by high-performance liquid chromatography.

A simple, efficient, and comprehensive technique for the purification, identification, and quantitation of the common steroid metabolites synthesized by the gonads of teleosts involving five systems of high-performance liquid chromatography (HPLC) was developed. Steroid standards were identified in HPLC by UV absorption at 254 nm or 280 nm, by differential refractive index, or by using radioactive standards. Metabolites that do not absorb UV light and are not resolved in the isocratic HPLC systems were identified in thin-layer chromatography following purification by HPLC. By using this technique, most of the steroid metabolites, including some polar metabolites, synthesized by the gonadal tissues of the teleosts can be purified within three steps of chromatography. The HPLC systems reported here are also useful in identifying the chromium trioxide oxidized products of metabolites, such as triols and tetrols, which considerably narrows down the number of probable metabolites.

Animals↗
PubMed1990

In vitro metabolism of progesterone, 17-hydroxyprogesterone, and 17,20 beta-dihydroxy-4-pregnen-3-one by ovaries of the common carp Cyprinus carpio: production rates of polar metabolites.

[14C]Progesterone, 17-[3H]hydroxyprogesterone, and 17,20 beta-[3H]dihydroxy-4-pregnen-3-one (17,20 beta P) were incubated for 1, 3, 6 or 24 hr with ovaries from carp which had received injections of either carp pituitary extract or saline. All three substrates were very rapidly metabolized to polar products, but 17,20 beta P was not detected as a metabolite of either progesterone or 17-hydroxyprogesterone. The major metabolite in all incubations was very similar, but not identical, in chemical and chromatographic properties to 5 beta-pregnane-3 alpha, 6 alpha, 17,20 beta-tetrol. A compound isopolar with 5 beta-pregnane-3 alpha, 6 alpha, 17,20 alpha-tetrol was isolated only in incubations of progesterone and 17-hydroxyprogesterone. It is suggested that hydroxylation and reduction may be a deactivation mechanism allowing 17,20 beta P to build up as an intermediate, and active maturation inducing steroid, only in response to the ovulatory gonadotrophin surge, thus assisting in synchrony of oocyte maturation.

17-alpha-Hydroxyprogesterone↗
PubMed1989

Interactions between oocytes of different maturational stages in the carp Cyprinus carpio: effects on maturational and steroidogenic activity in vitro.

Ovarian fragments from carp which had received injections of saline (control) or carp hypophysial homogenate (primed) were incubated both alone and a cocultures of primed and control tissue in the presence of carp pituitary extract. The results showed that the cocultures were not simply the sums of separate incubations. Oocyte maturation was retarded in primed tissue but advanced in control tissue and concentrations of 17,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta P) in the medium were significantly lower than that expected from separate incubations. The results indicate that local factors may act to synchronize oocyte maturation throughout the ovary to enable spawning of the maximum number of eggs.

Animals↗
PubMed1987

Effect of gonadectomy and hypophysectomy on plasma steroid levels in male and female lampreys (Lampetra fluviatilis, L.).

Testosterone, estradiol, and dehydroepiandrosterone (T, E2, and DHA) were measured by RIA in plasma samples from three groups of sexually immature male and female (male, female) river lampreys: (I) intact, (II) gonadectomized, or (III) with pro- and mesoadenohypophysis removed (hypophysectomized). T levels were around 0.1 ng/ml in both I male and I female and increased significantly in all operated groups, especially in II male, to 1.2 ng/ml. E2 levels were between 0.7 and 1 ng/ml in I male and I female and were significantly elevated only in II male to 2.0 ng/ml. DHA levels showed significant decreases, from around 0.9 ng/ml in I male and I female, in both operated groups. It is suggested that T and E2 are secreted from a nongonadal source in both sexes and then converted to biologically active sex hormones in the gonads. Therefore T and E2 do not decrease, and may even accumulate, in the blood after gonadectomy. Since extirpation of the pro- and mesoadenohypophysis was not followed by a decrease in T and E2, their secretion may be stimulated by a hormone from another part of the pituitary such as the metaadenohypophysis.

Animals↗
PubMed1987

The temporal sequence of changes in oocyte maturation and ovarian steroid hormone production during induced ovulation in the common carp, Cyprinus carpio.

Oocytes taken from carp sacrificed 3-24 hr after injection with either carp hypophysial homogenate (chh) (primed) or saline (control) were incubated with or without chh for 24 hr at 20 degrees. In oocytes from the primed fish the percentage of peripheral germinal vesicles at sacrifice progressively increased with time from injection. No such change occurred in control fish. After incubation with chh, tissue from primed fish showed a progressive increase in oocyte maturity with increasing time between priming and sacrifice, with germinal vesicle breakdown (GVBD) in 50% of the oocytes in incubations begun 24 hr after priming. In contrast, incubated tissue from control fish showed no variation with time between saline injection and sacrifice, and oocyte maturity did not exceed 50% with peripheral germinal vesicles. GVBD was not significant in these fish. 17-Hydroxyprogesterone, testosterone, and testosterone glucuronide production in vitro showed no major changes with the interval between injection and sacrifice, nor between control and primed fish. In vitro production of 17,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta P), however, increased significantly between tissue taken from animals at 3 and at 6 hr after injection of chh, and thereafter remained unchanged. 17,20 beta P production preceded the increase in GVBD in primed fish but neither this hormone nor GVBD was found in incubations of control fish, supporting the suggestion that 17,20 beta P is the maturation-inducing hormone in carp. Steroid production was not detectable in the absence of chh in the incubation medium and oocyte maturation showed little advance on that at sacrifice.(ABSTRACT TRUNCATED AT 250 WORDS)

17-alpha-Hydroxyprogesterone↗
PubMed1987

Effects of carp hypophyseal homogenate doses, incubation times, and temperatures on carp oocyte maturation and steroidogenesis in vitro.

Ovarian tissue from carp which had received injections of either saline or carp hypophyseal homogenate (chh) 24 hr prior to sacrifice was incubated for 8, 16, or 24 hr at 4, 15, 20, or 25 degrees with 0, 30, 100, or 200 micrograms chh. 17,20 beta-Dihydroxy-4-pregnen-3-one (17,20 beta P) was produced only by chh-primed tissue, but there was no difference between the two groups in production of testosterone, 17-hydroxyprogesterone, or testosterone glucuronide. Production of all steroids was greatest at 20 degrees which also corresponds to the optimal temperature for germinal vesicle breakdown in primed tissue. While yields of testosterone, 17-hydroxyprogesterone, and 17,20 beta P decreased with time, those of testosterone glucuronide tended to increase, suggesting further metabolism to conjugated and/or reduced metabolites. Germinal vesicle migration in control fish, and GVBD in primed fish, showed no change after 8 hr. The results indicate that the induction of both germinal vesicle migration and the potential for synthesis of 17,20 beta P by the priming dose of chh are of primary importance in the induced ovulation of carp.

Animals↗
PubMed1986

Autoradiographic localization of gonadotrophin receptors in ovaries of the common carp, Cyprinus carpio L.

Binding sites for carp gonadotrophin have been located in carp ovaries using [125I]labeled gonadotrophin and autoradiography. The radioactive gonadotrophin was displaced from tissue by unlabeled gonadotrophin or carp hypophysial homogenate in a dose-dependent fashion. No binding of gonadotrophin was found in previtellogenic oocytes but binding appeared with the first indications of vitellogenesis. In the smaller vitellogenic oocytes binding was uniformly distributed in the follicular envelope, but in the largest oocytes binding was restricted to the interstitial tissue. In these more mature oocytes gonadotrophin was also found within the oocyte and appeared to migrate toward the nucleus. The relationship between binding location, steroidogenesis, and oocyte maturation is discussed. We found no evidence for specific binding of [125I]thyroxine under comparable conditions.

Animals↗
PubMed1986

Steroidogenesis by gonads of a viviparous teleost, the sailfin molly (Poecilia latipinna), in vitro and in vivo.

Gonads of Poecilia latipinna transformed [3H]testosterone into a number of reduced and conjugated metabolites in high yield in vitro. In the male 5 beta-androstane-3 alpha, 17 beta-diol, 5 beta-androstane-3 beta, 17 beta-diol, and their "sulphates" were identified. The only 11-oxygenated androgen detected was a compound tentatively identified as 5 beta-androstane-3 beta, 11 beta, 17 beta-triol. In ovarian incubates androstenedione, 5 beta-androstane-3 alpha, 17 beta-diol and its glucuronide, testosterone glucuronide, and 5 beta-androstane-3 alpha, 17 beta-diol glucuronide were identified. Highest yields of the ovarian glucuronides coincided with the termination of vitellogenesis which may indicate a possible pheromonal role of these conjugates. In vivo plasma levels of estradiol in the female were correlated with vitellogenesis and fell markedly after castration or hypophysectomy. In males the plasma concentrations of testosterone, 11-ketotestosterone and 11 beta-hydroxytestosterone and their conjugates were variable and not apparently correlated with testicular weight, but they were reduced to undetectable levels by castration and hypophysectomy. The results suggest that 5 alpha- and 5 beta-reduced steroids may play a role in the reproductive endocrinology of P. latipinna and that measurements of only the "classical" steroid hormones in this and possibly other species may give only a partial and misleading picture of endocrine changes.

17-alpha-Hydroxyprogesterone↗
PubMed1985

Hormonal changes during induced ovulation of the carp, Cyprinus carpio.

The changes in plasma concentrations of eight steroids (testosterone, testosterone glucuronide, estradiol, estradiol glucuronide, 17-hydroxyprogesterone, 17,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta P), deoxycorticosterone, and cortisol) have been followed in three individual carp, Cyprinus carpio, during ovulation induced by carp pituitary extract. Deoxycorticosterone and estradiol glucuronide were not detectable and small amounts of 17,20 beta P were found only in one fish. A priming injection of pituitary extract, administered 24 hr before ovulation, stimulated an increase in testosterone 3-6 hr later, followed by an increase in estradiol. The second injection of pituitary extract given 12 hr after the priming dose, resulted in a second peak of testosterone which was accompanied by a peak of testosterone glucuronide, a conjugate which was usually formed in only small amounts following the priming dose. A sharp peak of 17-hydroxyprogesterone followed the second stimulation and it is suggested that this, rather than 17,20 beta P, may be the natural inducer of maturation in carp. Although cortisol levels showed large variations, they appeared to be stimulated by the priming dose of pituitary extract. Levels of all steroids, except for cortisol, fell rapidly after ovulation.

17-alpha-Hydroxyprogesterone↗
PubMed1985

The effect of temperature on testicular steroid production in the rainbow trout, Salmo gairdneri, in vivo and in vitro.

The effect of temperature on steroidogenesis in the male rainbow trout has been studied both in vitro using endogenous precursors under gonadotrophin stimulation and in vivo in fish held for 2 weeks at three different temperatures. In vitro, the optimum temperature for formation of testosterone and its 11-oxygenated derivatives was 10 degrees, whereas glucuronide formation showed an optimum at 18 degrees. In vivo, plasma levels of testosterone and 11-keto-testosterone were significantly higher at 6 than at 17 degrees, whereas glucuronide levels showed no significant difference. Milt was obtained only from fish held at 6 and 12 degrees. The optimum temperature for free steroid formation in response to gonadotrophin stimulus is shown to be dependent upon glucuronyl transferase content, and its progressive increase during the reproductive cycle may provide a mechanism for the inhibition of free steroid synthesis and hence spermiation at elevated temperatures where gamete survival is poor.

Animals↗
PubMed1984

Temperature regulation of ovarian steroid production in the common carp, Cyprinus carpio L., in vivo and in vitro.

The effect of temperature on ovarian steroid production in the common carp, Cyprinus carpio L., has been studied in vitro with exogenous and endogenous precursors, and in fish held at three different temperatures in vivo. With radioactive testosterone as substrate, the major metabolite was testosterone glucuronide, but androstenedione and 5 alpha-androstane-3 beta,17 beta-diol were also identified. 5 alpha-Androstane-3 beta,7 alpha,17 beta-triol was tentatively identified and two other polar metabolites were isolated, one of which was convertible to this triol. A significant increase in production of most metabolites occurred between 20 and 24 degrees. Production of estradiol and testosterone from endogenous substrate under gonadotrophin stimulation in vitro showed a marked temperature dependence, but the response was closely related to ovarian maturity. Stage 4-5 ovaries produced testosterone, while late Stage 3 tissue produced only estradiol. Neither steroid was produced in significant quantities by less mature ovaries. The results indicate that the "switch off" of ovarian aromatase activity at the end of vitellogenesis is actuated by an ovarian rather than by a pituitary factor. Secretion of testosterone and estradiol showed a very significant change with temperature with the optimum at 24-29 degrees. Profiles for individual fish show that this optimal range is extremely narrow, particularly for estradiol, where secretion may increase as much as twentyfold over 5 degrees. The results in general correlate well with 24 degrees as the most favourable temperature for reproduction in carp. Plasma concentrations of testosterone and estradiol closely paralleled the in vitro secretion rates of these hormones. Plasma testosterone levels were greatest in the most mature fish, whereas plasma estradiol was significantly higher in late Stage 3 fish than in those of greater or lesser ovarian maturity. More Stage 4 and 5 fish were found in the group held at 24 degrees than at 20 or 29 degrees for 4 weeks, but all groups contained a high proportion of early Stage 3 fish.

Androstane-3,17-diol↗
PubMed1984

The effect of cadmium on steroidogenesis by testes of the rainbow trout, Salmo gairdneri.

Testes of the rainbow trout were incubated in the presence of 0, 0.05, 0.5 and 5 mM cadmium (Cd). Production of those steroids measured was stimulated by 0.05 and 0.5 mM cadmium. Yields of testosterone (T) and 11 beta-hydroxytestosterone (beta) were significantly increased at these concentrations, but there was little effect on glucuronyl transferase and 11 beta-hydroxysteroid dehydrogenase enzyme activities. Cd-induced alteration of the hormonal balance may result in perturbation of reproductive development.

Animals↗
PubMed1983

The effect of temperature and gonadotropin on testicular steroidogenesis in Sarotherodon (Tilapia) mossambicus in vitro.

Testes of sexually mature Sarotherodon mossambicus were incubated at 15, 22, 30, and 40 degrees with (a) tritiated testosterone and (b) salmon pituitary extract. Formation of 11-keto- and 11 beta-hydroxytestosterone from the tritiated precursor showed little change in yield between 15 and 30 degrees but yields of glucuronides rose dramatically between 22 and 30 degrees and a significant rise was observed for formation of 5 beta-androstane-3 alpha, 17 beta-diol between 15 and 40 degrees. Yields of 3 alpha, 17 beta-dihydroxy-5 beta-androstan-11-one followed a pattern similar to that of 11-ketotestosterone. With endogenous precursors under the stimulation of salmon pituitary extract, yields of testosterone, 11-ketotestosterone, and 11 beta-hydroxytestosterone were maximal at 22 degrees after which they declined to very low levels at 40 degrees. Yields of testosterone and 11-ketotestosterone glucuronides while showing a peak at 22 degrees declined much more slowly at higher temperatures than did those of the free steroids. In the absence of pituitary stimulation, levels of all steroids were below the limits of detection. Plasma levels of testosterone (15.3 +/- 1.5 ng/ml), 11-ketotestosterone (5.3 +/- 2.7 ng/ml), 11 beta-hydroxytestosterone (5.5 +/- 2.6 ng/ml), and their glucuromides (1.5 +/- 0.5, 0.14 +/- 0.1, and 1.5 +/- 0.5 ng/ml, respectively) were measured in fish held at 25 degrees. A rapid conchromatographic method for the assay of the three free steroids is described and the results are shown to be comparable to those obtained after chromatography.

Androgens↗