Ovarian steroid concentrations in rats approaching first ovulation

1984 ◽  
Vol 100 (3) ◽  
pp. 281-286 ◽  
Author(s):  
A. I. Toorop ◽  
H. M. A. Meijs-Roelofs ◽  
P. Kramer ◽  
W. J. de Greef
Keyword(s):  
Ovarian Tissue ◽  
Inverse Correlation ◽  
Serum Concentrations ◽  
Ovarian Steroid ◽  
Steroid Production ◽  
Intact Control ◽  
Ovarian Steroids ◽  
Unilateral Ovariectomy ◽  
Low Levels

ABSTRACT Steroid concentrations were studied in ovarian tissue obtained by means of unilateral ovariectomy during a 10-day period preceding first ovulation. Furthermore, the levels of progesterone were measured in this period in the serum of simultaneous intact control rats. Ovarian concentrations of testosterone and oestradiol were at about 70 and 15 fmol/mg ovary respectively from 10 to 4 days before first ovulation; they clearly increased to a maximum of 170 and 120 fmol/mg ovary during the last 1–3 days before first ovulation. Ovarian concentrations of 5α-reduced androgens (i.e. androsterone and 5α-androstane-3α, 17β-diol) were high (up to 2500 fmol/mg ovary) from 7 to 4 days before first ovulation, whereas low levels (500–750 fmol/mg ovary) were present during the last 3 days before ovulation. Both ovarian and serum concentrations of progesterone were constantly low (at 500–1000 fmol/mg ovary and at 17–32 nmol/l respectively) from 10 days to 1 day before first ovulation. An inverse correlation was observed between the ovarian content of 5α-reduced androgens and that of oestradiol, which is in agreement with the existence of a prepubertal shift in pathways of steroid production; this shift seems to take place between 4 and 3 days before first ovulation. Changes in ovarian steroids on the day of the first pro-oestrus were fully comparable to those at pro-oestrus in adults: relatively high levels of ovarian testosterone and oestradiol, reaching values of 339 and 711 fmol/mg ovary respectively during the morning, an increase in progesterone (from 986 to > 40 000 fmol/mg ovary) first observed at 14.00 h and a decline, observed at 17.00 h, in ovarian testosterone and oestradiol concentration, resulting in values of 9 and 3 fmol/mg ovary respectively at 21.00 h. J. Endocr. (1984) 100, 281–286

ABSENCE OF COMPENSATORY OVARIAN HYPERTROPHY IN RATS WITH ANTERIOR HYPOTHALAMIC LESIONS

1961 ◽  
Vol 36 (2) ◽  
pp. 180-184 ◽  
Author(s):  
Béla Flerkó ◽  
Vera Bárdos
Keyword(s):  
Essential Role ◽  
Ovarian Tissue ◽  
Vaginal Smear ◽  
Corpora Lutea ◽  
Vaginal Smears ◽  
Hypothalamic Area ◽  
Unilateral Ovariectomy ◽  
Hypothalamic Lesions ◽  
Oestrogen Level ◽  
Stimulation Of

ABSTRACT Absence of compensatory ovarian hypertrophy in »constant oestrus rats« from lesions in the anterior hypothalamic area suggests that nervous elements localized in this region play an essential role in the stimulation of gonadotrophin output by diminution of the blood oestrogen level. The constant vaginal oestrus after unilateral ovariectomy in the majority of animals was, however, repeatedly interrupted by vaginal smears of a dioestrous type. The appearance of a dioestrous vaginal smear in the »hypothalamic constant oestrus rats« is often associated with some luteinisation. It is assumed that diminution of the blood oestrogen level by reduction of ovarian tissue in these animals may bring about a release of LH sufficient to cause formation of corpora lutea.

scholarly journals MicroRNA Zma-miR528 Versatile Regulation on Target mRNAs during Maize Somatic Embryogenesis

2021 ◽  
Vol 22 (10) ◽  
pp. 5310
Author(s):  
Eduardo Luján-Soto ◽  
Vasti T. Juárez-González ◽  
José L. Reyes ◽  
Tzvetanka D. Dinkova
Keyword(s):  
Somatic Embryogenesis ◽  
Immature Embryo ◽  
Inverse Correlation ◽  
Total Rna ◽  
Target Mrnas ◽  
Sequence Complementarity ◽  
Low Levels ◽  
Embryogenic Callus Induction ◽  
Regenerated Plantlets ◽  
Polysome Fraction

MicroRNAs (miRNAs) are small non-coding RNAs that regulate the accumulation and translation of their target mRNAs through sequence complementarity. miRNAs have emerged as crucial regulators during maize somatic embryogenesis (SE) and plant regeneration. A monocot-specific miRNA, mainly accumulated during maize SE, is zma-miR528. While several targets have been described for this miRNA, the regulation has not been experimentally confirmed for the SE process. Here, we explored the accumulation of zma-miR528 and several predicted targets during embryogenic callus induction, proliferation, and plantlet regeneration using the maize cultivar VS-535. We confirmed the cleavage site for all tested zma-miR528 targets; however, PLC1 showed very low levels of processing. The abundance of zma-miR528 slightly decreased in one month-induced callus compared to the immature embryo (IE) explant tissue. However, it displayed a significant increase in four-month sub-cultured callus, coincident with proliferation establishment. In callus-regenerated plantlets, zma-miR528 greatly decreased to levels below those observed in the initial explant. Three of the target transcripts (MATE, bHLH, and SOD1a) showed an inverse correlation with the miRNA abundance in total RNA samples at all stages. Using polysome fractionation, zma-miR528 was detected in the polysome fraction and exhibited an inverse distribution with the PLC1 target, which was not observed at total RNA. Accordingly, we conclude that zma-miR528 regulates multiple target mRNAs during the SE process by promoting their degradation, translation inhibition or both.

scholarly journals Fertility Preservation in Girls with Turner Syndrome: Prognostic Signs of the Presence of Ovarian Follicles

2009 ◽  
Vol 94 (1) ◽  
pp. 74-80 ◽  
Author(s):  
Borgström Birgit ◽  
Hreinsson Julius ◽  
Rasmussen Carsten ◽  
Sheikhi Maryam ◽  
Fried Gabriel ◽  
...  
Keyword(s):  
Turner Syndrome ◽  
Fertility Preservation ◽  
Chromosomal Abnormalities ◽  
Ovarian Tissue ◽  
Ovarian Follicle ◽  
University Hospital ◽  
Serum Concentrations ◽  
Pubertal Stage ◽  
Group 12 ◽  
Tissue Piece

Abstract Context: Many girls with Turner syndrome have follicles in their ovaries at adolescence. Objective: Our objective was to study which girls might benefit from ovarian tissue freezing for fertility preservation. Design: Clinical and laboratory parameters and ovarian follicle counts were analyzed among girls referred by 25 pediatric endocrinologists. Subjects and Setting: Fifty-seven girls with Turner syndrome, aged 8–19.8 yr, were studied at a university hospital. Interventions: Ovarian tissue was biopsied laparoscopically, studied for the presence of follicles, and cryopreserved. Blood samples were drawn for hormone measurements. Main Outcome Measures: Presence of follicles in the biopsied tissue related to age, signs of spontaneous puberty, karyotype, and serum concentrations of gonadotropins and anti-Müllerian hormone were assessed. Results: Ovarian biopsy was feasible in 47 of the 57 girls. In 15 of the 57 girls (26%), there were follicles in the tissue piece analyzed histologically. Six of seven girls (86%) with mosaicism, six of 22 (27%) with structural chromosomal abnormalities, and three of 28 with karyotype 45X (10.7%) had follicles. Eight of the 13 girls (62%) with spontaneous menarche had follicles, and 11 of the 19 girls (58%) who had signs of spontaneous puberty had follicles. The age group 12–16 yr had the highest proportion of girls with follicles. Normal FSH and anti-Müllerian hormone concentrations for age and pubertal stage were more frequent in girls with follicles. Conclusions: Signs of spontaneous puberty, mosaicism, and normal hormone concentrations were positive and statistically significant but not exclusive prognostic factors as regards finding follicles.

Seasonal changes of steroid concentrations in seminal plasma of a European wild boar

1984 ◽  
Vol 107 (3) ◽  
pp. 425-427 ◽  
Author(s):  
D. Schopper ◽  
J. Gaus ◽  
R. Claus ◽  
H. Bader
Keyword(s):  
Wild Boar ◽  
Seminal Plasma ◽  
Seasonal Pattern ◽  
Plasma Concentrations ◽  
Boar Taint ◽  
Steroid Production ◽  
European Wild Boar ◽  
Clear Seasonal Pattern ◽  
Boar Semen ◽  
Low Levels

Abstract. The influence of season on testicular steroid production as a parameter of testicular function has been studied in a wild boar. Semen was collected once weekly while it served the dummy. In seminal plasma concentrations of the following steroids were determined by radioimmunoassay: unconjugated testosterone, conjugated testosterone, unconjugated total oestrogens, conjugated total oestrogens and 5α-androst-16-en-3-one ('boar-taint steroid'). All steroids showed a clear seasonal pattern with highest concentrations in autumn and early winter and low levels from January to July. Maxima during the rutting season were 10–25 times greater than average values out of season. During a 2-month-period (mid-July until mid-September) libido was abolished and the wild boar refused to mount the dummy. These results indicate that the seasonal variation in testicular steroid production by the wild boar, regulated by photoperiod, are similar to those of the domestic boar.

Migraine and ovarian steroid hormones

Cephalalgia ◽  
1997 ◽  
Vol 17 (20_suppl) ◽  
pp. 12-16 ◽  
Author(s):  
Kma Welch
Keyword(s):  
Steroid Hormones ◽  
Clinical Presentation ◽  
Current Knowledge ◽  
Epidemiological Data ◽  
Special Treatment ◽  
Ovarian Hormone ◽  
Ovarian Steroid ◽  
Ovarian Steroids ◽  
Treatment Considerations ◽  
Hormone Sensitive

This chapter reviews clinical and epidemiological data that support a role for ovarian steroid hormones in the migraine syndrome. Changes in the clinical presentation of migraine are discussed on the basis of current knowledge of biochemistry and pharmacology of ovarian steroids. Finally, special treatment considerations of ovarian hormone-sensitive migraine are discussed.

Physiological Health of Common Bully (Gobiomorphus cotidianus) in the Tarawera and Rangitaiki Rivers of New Zealand: Evidence of Diminished Ecological Effects of Pulp and Paper Effluents in Wild Fish Populations

2010 ◽  
Vol 45 (2) ◽  
pp. 223-233 ◽  
Author(s):  
Michael J. Landman ◽  
Natalie A. Bleackley ◽  
Nicholas Ling ◽  
Michael R. van den Heuvel
Keyword(s):  
New Zealand ◽  
Ovarian Tissue ◽  
Microscopic Analysis ◽  
Pulp And Paper ◽  
Steroid Production ◽  
River Population ◽  
Tissue Samples ◽  
Stage Of Development ◽  
Pulp And Paper Effluent ◽  
Gobiomorphus Cotidianus

Abstract This study examined the comparative physiological health of the endemic New Zealand common bully (Gobiomorphus cotidianus) in the Tarawera and Rangitaiki Rivers. Bully were sampled downstream of pulp and paper effluent inputs in the Tarawera River and compared with a similar inland population in the Rangitaiki River. Condition factor and liver somatic index did not differ between populations, but Tarawera River bullies possessed larger gonads. Haematological assessments found smaller erythrocytes with reduced haemoglobin content, and increased leukocyte concentrations in Tarawera River females. Male and female Tarawera River bullies had significantly induced hepatic ethoxyresorufin-O-deethylase (EROD) activity. Greater ovarian follicular steroid production was also found for Tarawera River females. Microscopic analysis of ovarian tissue samples found no histopathological abnormalities in either population and indicated a slightly advanced vitellogenic stage of development in the Tarawera River population. It is concluded that the difference in steroid production between populations was most likely linked to gonad size and developmental status. In line with the disappearance of physiological effects in recent controlled laboratory and mesocosm pulp and paper effluent exposures, this study further demonstrates that, with the exception of EROD induction, characteristic pulp and paper effluent effects are not obvious in wild Tarawera fish.

scholarly journals Inverse correlation between tyrosine phosphorylation and collagenase production in chondrocytes

1990 ◽  
Vol 269 (3) ◽  
pp. 717-721 ◽  
Author(s):  
T F Cruz ◽  
G Mills ◽  
K P H Pritzker ◽  
R A Kandel
Keyword(s):  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Kinase Activity ◽  
Potent Inhibitor ◽  
Inverse Correlation ◽  
Cell Types ◽  
Proteoglycan Synthesis ◽  
Serum Concentrations ◽  
Tyrosine Phosphatases ◽  
Synergistic Increase

Collagenase production by chondrocytes appears to play a major role in the development of osteoarthritis. Although the mechanisms regulating collagenase production by chondrocytes are not known, incubation of bovine chondrocytes in serum markedly decreases collagenase production. Since serum has been demonstrated to increase levels of phosphotyrosine (P-Tyr) in several cell types, we determined the effect of altering intracellular levels of P-Tyr on collagenase production. Both orthovanadate, a potent inhibitor of tyrosine phosphatases, and serum caused a marked increase in tyrosine phosphorylation. The increase in P-Tyr was associated with a decrease in the production of collagenase, suggesting that two processes may be linked. Orthovanadate caused an increase in P-Tyr in the absence of serum, suggesting that P-Tyr levels in resting chondrocytes are regulated through activity of both tyrosine kinases and phosphatases. Orthovanadate and serum induced a synergistic increase in P-Tyr levels, suggesting that serum functions through increasing kinase activity rather than decreasing phosphatase activity. In the absence of serum, concentrations of orthovanadate which maximally inhibited collagenase production primarily increased phosphorylation of a 36 kDa protein, suggesting that the phosphorylation of this protein may play a major role in regulating collagenase production. Orthovanadate had limited effects on chondrocyte proteoglycan synthesis, morphology or viability in the presence or absence of serum, suggesting that the decrease in collagenase production was not due to non-specific inhibition of protein synthesis or cellular toxicity. Inhibition of tyrosine phosphatases by orthovanadate or activation of tyrosine kinases by addition of serum correlated with the inhibition of collagenase production.

scholarly journals Regulation of steroidogenesis in fetal bovine ovaries: differential effects of LH and FSH

2016 ◽  
Vol 57 (4) ◽  
pp. 275-286 ◽  
Author(s):  
J J Allen ◽  
S L Herrick ◽  
J E Fortune
Keyword(s):  
Culture Medium ◽  
Fetal Life ◽  
Dependent Manner ◽  
Ovarian Steroid ◽  
Steroid Production ◽  
Steroid Synthesis ◽  
Primordial Follicles ◽  
Preovulatory Follicles ◽  
Fetal Bovine ◽  
Dose Dependent

In cattle, primordial follicles form before birth. Fetal ovarian capacity to produce progesterone and estradiol is high before follicle formation begins and decreases around the time follicles first appear (around 90 days of gestation). However, mechanisms that regulate steroid production during this time remain unclear. We hypothesized that LH stimulates progesterone and androgen production and that FSH stimulates aromatization of androgens to estradiol. To test this, we cultured pieces from fetal bovine ovaries for 10 days without or with exogenous hormones and then measured the accumulation of steroids in the culture medium by RIA. LH (100 ng/mL) alone increased the accumulation of progesterone, androstenedione, testosterone and estradiol. FSH (100 ng/mL) alone increased both progesterone and estradiol accumulation, but had no effect on androgens. Exogenous testosterone (0.5 µM) alone greatly increased estradiol accumulation and the combination of testosterone + FSH, but not testosterone + LH, increased estradiol relative to testosterone alone. Interestingly, exogenous testosterone and estradiol decreased progesterone accumulation in a dose-dependent manner. Because the highest dose of estradiol (0.5 µM) decreased progesterone accumulation, but increased both pregnenolone and androstenedione in the same cultures, endogenous estradiol may be a paracrine regulator of steroid synthesis. Together, these results confirm our initial hypotheses and indicate that LH stimulates androgen production in fetal bovine ovaries via the Δ5 pathway, whereas FSH stimulates aromatization of androgens to estradiol. These results are consistent with the two-cell, two-gonadotropin model of estradiol production by bovine preovulatory follicles, which suggests that the mechanisms regulating ovarian steroid production are established during fetal life.

scholarly journals Effects of`extra' ovarian tissue on ovulation number and ovarian steroids in rats

Reproduction ◽  
1976 ◽  
Vol 47 (1) ◽  
pp. 107-109 ◽  
Author(s):  
H. J. W. Chihal ◽  
S. C. Stone ◽  
R. D. Peppler
Keyword(s):  
Ovarian Tissue ◽  
Ovarian Steroids
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