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S Okinaga

Publications and source records attributed to S Okinaga.

At least 91 records · Page 5Linked to original sources
PubMed1986

Studies of metabolism of round spermatids: glucose as unfavorable substrate.

The exposure of spermatids to glucose in the absence of pyruvate and lactate resulted in an extremely low energy charge. The adenosine 5'-triphosphate (ATP) level rapidly declined and the fructose 1,6-bisphosphate (FBP) and triose levels increased. These changes were prevented by the addition of pyruvate or lactate. The levels of ATP and FBP were inversely correlated. In cells exposed to glucose, FBP did not flow appreciably through the step of glyceraldehyde 3-phosphate dehydrogenase (GA3PDH). The lactate level did not change. However, when pyruvate or lactate was administered to cells exposed to glucose, the FBP level declined rapidly. This drop was accompanied by a commensurate increase in lactate. In these cells, pyruvate transport was suppressed, and the pyruvate taken up by these cells was mostly oxidized in the tricarboxylic acid (TCA) cycle without its being reduced to lactate. In this case, the ATP level increased, but to a level still lower than existed before exposure to glucose. Furthermore, when kinetic studies on the activity of 6-phosphofructokinase (PFK) were carried out, PFK appeared to be fully activated at intracellular levels of fructose 6-phosphate, ATP and adenosine 5'-monophosphate (AMP). These results indicate that the rate of glucose metabolism in glycolysis depends heavily on the energy charge. In cells exposed to glucose, the sugar does not flow appreciably through the glycolytic pathway due to inhibition of GA3PDH. Moreover, the ATP level cannot be recovered fully from the lowest level by the addition of pyruvate or lactate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1985

A new radioimmunoassay for serum 16 alpha-hydroxyandrost-4-ene-3,17-dione with specific antiserum.

A radioimmunoassay system for serum 16 alpha-hydroxyandrost-4-ene-3,17-dione was developed with the use of rabbit antiserum against 16 alpha-hydroxyandrost-4-ene-3,17-dione-3-(O-carboxymethyl)oxime which was conjugated with bovine serum albumin. The antiserum was highly specific for 16 alpha-hydroxyandrost-4-ene-3,17-dione, with cross reactions to other steroids being less than 0.8% except for androst-4-ene-3,17-dione(3.4% cross reaction). Use of LH-20 column chromatography, however, clearly separated these two steroids. Pregnancy sera were measured with this assay system after an addition of labelled internal standard, extraction and separation by column chromatography. The lower limit of detection for 16 alpha-hydroxyandrost-4-ene-3,17-dione was 2 pg/tube. The mean recovery rate of the added standard was 98.3 +/- 8.8% (mean +/- SE). Intra- and inter-assay coefficients of variation were 8.6% (n = 6) and 12.1% (n = 7), respectively.

Amniotic Fluid↗
PubMed1984

The ontogeny of cytosol and nuclear progestin receptors in male rat brain and its male-female differences.

The fetal and postnatal development of the progestin receptor systems in the intact male rat brain was investigated by means of the in vitro cytosol binding and the nuclear exchange assay using [3H]R5020 [( 17 alpha-methyl-3H]17 alpha, 21-dimethyl-19-nor-4, 9-pregnadiene-3,20-dione). The cortical cytosol receptors, first detectable at day 0, rapidly increased at day 7, reaching a maximum at day 10, then gradually declined thereafter. The receptors in the HPOA appeared clearly at day 1, increased during the first 10 days, then remained constant at days 14-21. The postnatal developmental patterns of cytosol brain progestin receptors in males were essentially similar to those in females, but there were some differences between both sexes. The male HPOA at days 10-14 contained more receptors than the female one. Nuclear progestin binding was low in the neonatal male brain at days 1-3. Despite the low level of serum progesterone, the cortical nuclear binding suddenly increased at days 7-10, then remained high at days 14-21. A similar, though less pronounced, pattern was seen in the HPOA. The male pattern of nuclear binding, thus, essentially resembled the female one. However, lower binding in the cortex and, possibly, HPOA was found in males than in females at days 10-21. After progesterone injection postnatal male rats accumulated a lower concentration of progestin receptors in the cortex and, possibly, HPOA than similarly-treated females. It is concluded from these results that progestin receptors in male rat brain appear immediately after birth and develop differentially in the cortex and HPOA. The sudden onset of increased nuclear translocation of endogenous progestin receptor complexes may occur in the brain at around days 7-10. There is a marked sex difference in the nuclear progestin receptor system in the postnatal brain, particularly the cortex. Moreover, the postnatal male brain has lower capacities of nuclear receptor translocation than does the female one. The progestin receptor system in the cortex and, possibly, HPOA of rats in the early postnatal life might be involved with some processes in the mechanism of sexual differentiation of the brain.

Animals↗
PubMed1984

Metabolism of pachytene primary spermatocytes from rat testes: pyruvate maintenance of adenosine triphosphate level.

Pachytene primary spermatocytes were prepared and examined for energy metabolism. When the cells were incubated with various substrates (glucose, fructose, pyruvate and lactate) to measure their utilization of substrates and the degree of ATP synthesis, spermatocytes were observed to use pyruvate as much as lactate, but in amounts much greater than those of glucose or fructose. Pyruvate and lactate maintained ATP levels in spermatocytes, while only lactate did in round spermatids and residual bodies. Pyruvate (5 mM) did not inhibit ATP synthesis from lactate in spermatocytes, differing from its behavior in spermatids. Pyruvate was oxidized in the Krebs cycle for further oxidative phosphorylation and was not altered by addition of glucose. Pyruvate and lactate were interconverted, but the intracellular level of pyruvate remained unchanged (approx. 0.2 mM) when either pyruvate or lactate was added to the medium. The maximal activity of lactate dehydrogenase (LDH) of spermatocytes occurred at 0.3-0.7 mM pyruvate, and this enzyme promoted the conversion of pyruvate to lactate rather than the reverse reaction. In addition, activity assays of 11 glycolytic enzymes and concentration assays of glycolytic intermediates showed a possible regulatory role for glyceraldehyde-3-phosphate dehydrogenase (GA3PDH) in glycolysis. These observations suggested that spermatocytes differed strikingly from spermatids with respect to energy metabolism, even though glycolysis in the two categories of germinal cells was presumably regulated by GA3PDH.

Adenosine Triphosphate↗
PubMed1984

Metabolism of round spermatids: evidence that lactate is preferred substrate.

Glucose was utilized at a rate of 17.9 +/- 1.0 nmol X 10(6) cells-1 X h-1, with 5.2 and 9.5% accumulated as glucose and fructose 1,6-diphosphate, respectively, 79.6% transformed into lactate, 2% oxidized by the trichloroacetic acid cycle, and little metabolized by the pentose cycle. Glucose utilization increased and reached a maximum at 1 mM glucose. The ATP level was maintained by approximately 0.8 mM lactate, but not by glucose or pyruvate. Glucose decreased the ATP level to a value lower than the control level due partly to the fructose 6-phosphate-fructose 1,6-diphosphate futile cycle. In the presence of lactate (0.01-20 mM), pyruvate production was increased, but the intracellular level of pyruvate (0.2-0.3 mM) remained unchanged. Lactate dehydrogenase (LDH) activity was increased, at a maximum rate, by 0.1-0.2 mM pyruvate but was inhibited beyond 0.3 mM (Ki = 2.5 mM). The Km values of LDH for pyruvate and lactate were 24.4 +/- 4.2 microM and 2.36 +/- 0.14 mM, respectively. The importance of LDH in glucose and lactate metabolism by spermatids was described. These observations further support the hypothesis that lactate is the preferred substrate for spermatid metabolism.

Adenine Nucleotides↗
PubMed1983

Effects of ovarian steroids on the 17 alpha-hydroxylase activity toward progesterone in a human ovarian follicle at the late follicular phase.

The dominant follicle at the late follicular phase was obtained from a human ovary, the follicular wall was homogenized and centrifuged at 800 g. Then, the supernatant fluid was incubated with [14C]-progesterone and the radioactive products were quantitated. 17-Hydroxyprogesterone, 16 alpha-hydroxyprogesterone and androstenedione were identified under the present experimental conditions. The apparent KM value of the 17 alpha-hydroxylase toward progesterone was 0.19 +/- 0.01 microM. Various ovarian steroids (17-hydroxyprogesterone, 20 alpha-hydroxy-4-pregnen-3-one. 16 alpha-hydroxyprogesterone, androstenedione, testosterone, estrone and estradiol-17 beta) were tested for their effects on this hydroxylase activity. Among them, 20 alpha-hydroxy-4-pregnen-3-one and 17-hydroxyprogesterone inhibited on the enzyme activity, significantly. They acted competitively and their Ki values were 0.23 microM for 20 alpha-hydroxy-4-pregnen-3-one and 0.54 microM for 17-hydroxyprogesterone.

Adult↗
PubMed1983

Acute effects of maternal stress on fetal blood catecholamines and hypothalamic LH-RH content.

The acute effects of maternal stress (restraint for 20 to 140 min) on the plasma levels of epinephrine, norepinephrine and dopamine in pregnant rats and their fetuses as well as on the catecholamine content of fetal adrenals and the LH-RH content of fetal hypothalami, were investigated at day 22 of gestation. Despite of a relatively moderate increase of maternal plasma catecholamines a significant increase of norepinephrine (p less than 0.05) and dopamine (p less than 0.05) levels in plasma of the fetuses 30 min after starting maternal stress was observed. The fetal blood concentrations of catecholamines before and during maternal stress were significantly higher than those of the mothers (p less than 0.05 to p less than 0.001). A gradual decrease of the fetal adrenal content of epinephrine and norepinephrine was found, whereas an unchanged content of dopamine of fetal adrenals was registered during maternal restraining. The LH-RH content of fetal hypothalami rose significantly (p less than 0.005) 60 min after starting maternal stress and returned to initial values 140 min after starting restraining.

Adrenal Glands↗
PubMed1983

[Fundamental and clinical studies on T-1982 (cefbuperazone) in the field of obstetrics and gynecology].

Fundamental and clinical studies on T-1982 (cefbuperazone) in the field of obstetrics and gynecology were carried out. Transfer of T-1982 to various location in uterus tissue was more than 10 micrograms/g over 2 hours after T-1982 1 g intravenous injection. T-1982 was distributed in cervix uteri at the highest concentration followed by ovarium, oviduct, portio vaginalis, endometrium and myometrium. Mean transfer ratio of cervix uteri to uterus arterial blood was 67.6%. Ten cases of gynecological infections receiving T-1982 demonstrated "good" results in 9 cases, except 1 case excluded from the evaluation of efficacy. Neither side effect nor clinical test abnormality was observed. Based on the results of basic and clinical studies, T-1982 is considered to have efficacy in the treatment of gynecological infections.

Adnexa Uteri↗
PubMed1982

Regulation of glucose metabolism by adenine nucleotides in round spermatids from rat testes.

Regulation of glucose metabolism in glycolysis by round spermatids was studied. Assay of activities of 11 glycolytic enzymes in cell-free spermatid extracts showed that hexokinase, phosphofructokinase, and glyceraldehyde-3-phosphate dehydrogenase had the lowest activities. When the cells were incubated with glucose (10 mM), the intracellular level of ATP fell rapidly and 5'-AMP increased. The ADP level remained unchanged. During incubation with glucose, fructose-1,6-bisphosphate, dihydroxyacetone phosphate, and glyceraldehyde-3-phosphate were accumulated without any change in a mass action ratio of fructose bisphosphate aldolase. Glyceraldehyde-3-phosphate dehydrogenase appeared to play a regulatory role in glycolysis. Glyceraldehyde-3-phosphate dehydrogenase was inhibited by the following compounds (Ki values in parentheses): adenosine (4.34 mM), 5'-AMP (3.50 mM), ADP (2.35 mM), ATP (5.34 mM), and 3',5'-cAMP (0.60 mM). In each case, the inhibition was competitive with NAD (Km = 0.20 mM). The 2'-hydroxy group of the adenine-linked ribose moiety was essential for binding. The compounds adenine, 2'-deoxyadenosine, 2'-AMP, 3'-AMP, CTP, GTP, UTP, and NADP showed little inhibition. These findings suggest that regulation of glycolysis in round spermatids by glyceraldehyde-3-phosphate dehydrogenase is most likely and that glyceraldehyde-3-phosphate dehydrogenase is inhibited by the adenine nucleotides, particularly by 5'-AMP and ADP as inhibitors competitive with NAD.

Adenine Nucleotides↗
PubMed1982

Metabolism of [14C]-C21 steroids in the human fetal ovaries.

The incubation of [14C]-pregnenolone with the mince of human fetal ovary produced progesterone. 17-hydroxypregnenolone, 5-pregnene-3 beta, 20 alpha-diol. 5-pregnene-3 beta, 17 alpha, 20 alpha-triol and 5 alpha-pregnan-3,20-dione. The other 7 tissues, uterus, liver, intestine, skin, kidney, lung and pancreas, obtained from the same fetus were also able to produce some of these metabolites. When [14C]-pregnenolone, progesterone or 17-hydroxyprogesterone was incubated with 800 g supernatant of fetal ovaries, progesterone, 17-hydroxypregnenolone and 5-pregnene-3 beta, 20 alpha-diol were formed from pregnenolone, 17-hydroxyprogesterone and 20 alpha-hydroxy-4-pregnen-3-one were formed from progesterone and 17 alpha, 20 alpha-dihydroxy-4-pregnen-3-one was formed from 17-hydroxyprogesterone. These results indicate that the fetal ovary has the activities of 5-ene-3 beta-hydroxysteroid dehydrogenase, 17-hydroxylase, 20 alpha-hydroxysteroid dehydrogenase and 5 alpha-reductase.

17-alpha-Hydroxypregnenolone↗
PubMed1982

[Studies on the safe limit of variable decelerations during labor].

Ninety neonates who presented variable decelerations during labor were divided into two groups, according to the one-minute Apgar scores of greater than or equal to 8 and 7 less than or equal to. Only neonates of singleton pregnancies and cephalic presentations of 34 weeks gestation or more were included in the study. Several parameters of this fetal heart rate (FHR) pattern and the presence or absence of meconium staining were compared. Followings were found to be statistically significant. 1) The duration of the variable deceleration (less than 2 hours). 2) The FHR deceleration/uterine contraction ratio (less than 80%). 3) The absence of meconium staining. An effort was made to establish safe limits of variable decelerations. These are shown in parentheses. Based on both these data and findings of others, a multifactorial scoring system named a variable deceleration score was proposed for the proper management of this FHR pattern. Five variables were selected for the system. These were: The duration of variable decelerations, the FHR deceleration/uterine contraction ratio, the duration and amplitude of dips, and the presence or absence of meconium staining. The system scores from 0 to 2 for each of five factors, and was designed to be able to predict depressed neonates with the numerical increase of the score.

Female↗
PubMed1981

Changes in enzyme activities related to steroidogenesis in human ovaries during the menstrual cycle.

Follicles and corpora lutea were isolated from the ovaries of 25 patients at several stages of the normal menstrual cycle. To measure the steroidogenic enzyme activities, cell-free homogenates of the ovaries were incubated aerobically with 4-14C-labeled pregnenolone, progesterone, 17 alpha-hydroxyprogesterone, androstenedione, and testosterone in the presence of appropriate cofactor(s). The delta 5-3 beta-hydroxysteroid dehydrogenase plus delta 4-delta 5 isomerase activity in the follicle was low during early follicular phase (greater than 11 days before ovulation), but gradually increased toward ovulation and showed maximal values in the corpus luteum at the midluteal phase (6-10 days after ovulation). The activities of 17 alpha-hydroxylase and C-17-C-20 lyase in the follicle reached the highest value at the late follicular phase (within 5 days of ovulation), but markedly decreased after luteinization. 17 alpha-Hydroxylase activity in the corpus luteum increased again during the midluteal phase, whereas the activity of C-17-C-20 lyase remained at a low level throughout the luteal phase. The aromatase activity was low during the follicular phase, but increased markedly with luteinization. These findings are discussed in light of the known plasma steroid concentrations and their changes during the menstrual cycle.

3-Hydroxysteroid Dehydrogenases↗