INFLUENCE OF GONADOTROPHINS AND CYCLIC AMP ON CARBOHYDRATE AND PROTEIN METABOLISM IN THE IMMATURE RAT OVARY

1973 ◽  
Vol 72 (3) ◽  
pp. 425-437 ◽  
Author(s):  
Lars Hamberger ◽  
Hans Herlitz ◽  
Anita Sjögren
Keyword(s):  
Amino Acid ◽  
Cyclic Amp ◽  
Lactic Acid Production ◽  
Lactate Production ◽  
Bicarbonate Buffer ◽  
Immature Rat ◽  
Clear Dose Response ◽  
Old Rats ◽  
Rat Ovary

ABSTRACT Ovaries from rats varying in age between 5–12 days were incubated in Krebs bicarbonate buffer at 37°C containing 5.5 mmol/l glucose. A 2 h incubation in the presence of 0.01 μg/ml LH (NIH-LH-B6) caused an increase in lactic acid production as compared to controls, and a clear dose-response was demonstrated up to 100 μg/ml. In vitro the addition of 100 μg/ml FSH (NIH-FSH-S5) or 10 mmol/l cyclic AMP also caused stimulatory effects on lactate production. In experiments with ovaries from 8–9 day old rats, incubations were carried out in a medium containing 0.1 mmol/l [14C]AIB (α-aminoisobutyric acid), and the distribution ratios for this model amino acid were determined after 2 h incubation in the absence and presence of LH, FSH or cyclic AMP respectively. No hormonal effects were demonstrated, while cyclic AMP caused a significant increase in the [14C]AIB uptake. In further experiments ovaries from 9 day old rats were incubated in medium containing both [14C]AIB (0.1 mmol/l) and [3H]leucine (0.03 mmol/l). Four hours before the removal and incubation of the ovaries the rats were injected ip with FSH or LH (500 μg/100 g body weight) or saline. The distribution ratios of both [14C]AIB and [3H]leucine were significantly elevated in the FSH injected group while LH was ineffective. In similar experiments with 0.01 mmol/l [3H]proline it was also possible to demonstrate an increased incorporation of this amino acid into ovarian protein after a single FSH injection 2 h before the incubation.

STIMULATORY EFFECT OF FSH IN VITRO ON THE EXTRACELLULARLY ACTIVE CYCLIC AMP PHOSPHODIESTERASE IN THE PREPUBERTAL RAT OVARY

1976 ◽  
Vol 81 (2) ◽  
pp. 563-573 ◽  
Author(s):  
Gunnar Selstam ◽  
Sten Rosberg
Keyword(s):  
Cyclic Amp ◽  
Incubation Medium ◽  
Inorganic Phosphate ◽  
Kinetic Studies ◽  
Bicarbonate Buffer ◽  
Low Concentrations ◽  
Rat Ovary ◽  
Camp System ◽  
Burk Plot

ABSTRACT Intact prepubertal rat ovaries were incubated with radioactively labelled adenosine 3,′5′-cyclic monophosphate (cAMP) in Krebs bicarbonate buffer containing glucose. The rate of degradation of cAMP was determined by measuring the radioactivity in the medium after precipitation with Ba(OH)2 and ZnSO4. The fate of the nucleotide was followed by measuring the products in the incubation medium. Paper chromatography was used for the separation and identification of these products. It was found that cAMP was degraded to AMP, which in turn was degraded to inorganic phosphate (Pi) and adenosine. An uptake of labelled products was also observed. NIH-FSH-S9 (10 and 100 μg/ml), but not NIH-LH-B8 (0.1–100 μg/ml), increased the degradation of cAMP. Concomitantly, an increased accumulation of labelled adenosine and Pi as well as an increased uptake of labelled products were seen. Kinetic studies with low concentrations of cAMP (0.125–0.025 μmol/l) revealed an apparent Km value of 0.12 μmol/l for the phosphodiesterase (PDE) activity. FSH significantly changed the slope of the curve in the Lineweaver-Burk plot by increasing the PDE activity. The increased PDE activity in the presence of FSH is discussed in relation to earlier findings of differences in action between LH and FSH on the cAMP system in the prepubertal rat ovary.

REGULATION OF PRODUCTION IN VITRO OF 5α-ANDROSTANE-3α,17β-DIOL IN THE IMMATURE RAT OVARY

1971 ◽  
Vol 50 (3) ◽  
pp. 431-439 ◽  
Author(s):  
C. SPRINGER ◽  
B. ECKSTEIN
Keyword(s):  
Thin Layer ◽  
Steroid Synthesis ◽  
Immature Rat ◽  
Radioactive Precursor ◽  
Adult Rat ◽  
Immature Rats ◽  
Old Rats ◽  
Rat Ovary ◽  
Layer Chromatography

SUMMARY The pattern of steroid synthesis in vitro in ovarian homogenate of immature rats was investigated with [7α-3H]pregnenolone as radioactive precursor. The metabolites, progesterone, androstenedione, testosterone and 5α-androstane-3α,17β-diol were obtained in radiochemically pure form. The steroids were identified by fractionation, partition column and thin-layer chromatography, derivative formation and by crystallization to constant activity. The steroidogenic patterns at the ages of 21 and of 31 days were found to be similar, but different from the pattern reported for adult rat ovaries. At 34 days of age, 1 day before the onset of puberty, the percentage radioactivity converted to progesterone was about ten times higher than that at 31 days. The production in vitro of 5α-androstane-3α,17β-diol by ovarian homogenates of 34-day-old rats was shown to depend on the concentration of pregnenolone in the incubation mixture. These findings are discussed in relation to the mechanism of the onset of puberty in the female mammal.

Follicle-stimulating hormone-dependent estrogen secretion by rat Sertoli cells in vitro: Modulation by calcium

1991 ◽  
Vol 125 (3) ◽  
pp. 280-285 ◽  
Author(s):  
J. Alan Talbot ◽  
Ann Lambert ◽  
Robert Mitchell ◽  
Marek Grabinski ◽  
David C. Anderson ◽  
...  
Keyword(s):  
Sertoli Cells ◽  
Culture Medium ◽  
Follicle Stimulating Hormone ◽  
Dibutyryl Camp ◽  
Immature Rat ◽  
Estradiol Secretion ◽  
Old Rats ◽  
Stimulating Hormone

Abstract We have investigated the role of Ca2+ in the control of FSH-induced estradiol secretion by Sertoli cells isolated from 8-10 days old rats. Exogenous Ca2+ (4-8 mmol/1) inhibited FSH-stimulated E2 secretion such that, with 8 mmol/l Ca2+ and FSH (8 IU/l) E2 secretion decreased from 2091±322 to 1480±84 pmol/l (p<0.002), whilst chelation of Ca2+ in the culture medium with EGTA (3 mmol/l) increased E2 secretion from 360±45 to 1242±133 pmol/l) in the absence of FSH. Further, EGTA (3 mmol/l) markedly potentiated FSH (8 IU/l), forskolin (1 μmol/l) and dibutyryl cAMP (1 mmol/l)-stimulated E2 secretion. Addition of the Ca2+ ionophores, ionomycin (2-5 μmol/l) and A23187 (2 μmol/l), inhibited FSH (8 IU/l)-stimulated E2 secretion by >80%. The effect of ionomycin was totally reversible, whereas that of A23187 was irreversible. Ionomycin (5 μmol/l) had no effect on EGTA-induced E2 secretion in the absence of FSH, but reduced EGTA-provoked E2 secretion by 59% in the presence of FSH (8 IU/l). Similarly, forskolin- and dibutyryl cAMP-provoked E2 production was inhibited 46-50% by ionomycin (5 μmol/l). We conclude that FSH-induced E2 secretion from immature rat Sertoli cells is modulated by intra- and extracellular Ca2+.

Abstract 145: Glucose Depletion Is Essential For The Calorie-restriction-mediated Cardiac Angiogenesis Via Pka/ampk-dependent Autophagy.

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Akio Monji ◽  
Yasuko K Bando ◽  
Morihiko Aoyama ◽  
Toko Mitsui ◽  
Haruya Kawase ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cyclic Amp ◽  
Culture Media ◽  
Pressure Overload ◽  
Cardiovascular Effects ◽  
Tube Formation ◽  
Simultaneous Increase ◽  
Glucose Depletion ◽  
Vitro Analysis

Background: Caloric restriction (CR) promotes beneficial cardiovascular effects; however, its effects on cardiac angiogenesis remain unclear. We thus examined whether CR may modulate cardiac angiogenesis via activation of autophagy and seeked for the essential nutrient factor(s) that may be responsible for the CR-mediated angiogenesis. Methods: To confirm whether CR-induced angiogenic effects may be universally observed, we allocated 2 distinct heart failure models; #1 pressure overload (4 weeks) generated by transaortic constriction (TAC) and #2 diet-induced obesity (DIO) mice, as a model of diabetic cardiomyopathy. Male mice (14 w/o) were randomly allocated to a 4-week CR (TAC-CR and DIO-CR) and ad libitum (TAC-AL and DIO-AL). Cultured endothelial cells (ECs) were exposed to culture media of 1) ordinary composition, 2) glucose-depleted, 3) amino acid-depleted, and 4) serum-depleted condition. To visualize cardiac autophagic changes, GFP-LC3 mice were allocated to DIO and TAC treatment. Analyses for the changes in activities of autophagy (LC3-turnover assay and p62 level) and angiogenesis (tube formation and Akt/AMPK/eNOS activity) were evaluated. Results: Immunohistochemical analyses revealed that CR enhanced cardiac angiogenesis both in TAC and DIO mice. CR promoted increased in myocardial cyclic AMP concentration with concomitant PKA/AMPK/eNOS activation and the simultaneous increase in autophagic activity both in TAC and DIO hearts. Of note, cardiac Akt activity remains unchanged by CR. In vitro analysis revealed that glucose depletion, as well as forskolin (10 μM) and 8-bromo-cyclic AMP (1 mM), activated PKA/AMPK axis thereby facilitated angiogenesis and autophagy in ECs. The enhanced in vitro angiogenesis induced by glucose depletion and PKA enhancers was abrogated by autophagy inhibitor 3-MA treatment. PKA inhibitors (H89 and RP-cAMP) abrogated the increase in AMPK/eNOS phosphorylation levels induced by glucose depletion. Neither amino acid- nor serum-depletion had no effect on angiogenesis and autophagy. Conclusions: Glucose depletion is essential for the CR-mediated activation of cardiac angiogenesis and autophagy in a cAMP/PKA/AMPK-dependent fashion.

FOLLICLE GROWTH IN THE IMMATURE RAT OVARY

1978 ◽  
Vol 88 (2) ◽  
pp. 375-382 ◽  
Author(s):  
A. J. Hage ◽  
A. C. Groen-Klevant ◽  
R. Welschen
Keyword(s):  
Granulosa Cells ◽  
Tritiated Thymidine ◽  
Pulse Labelling ◽  
Follicle Growth ◽  
Immature Rat ◽  
Stage Of Development ◽  
Different Ages ◽  
Old Rats ◽  
Rat Ovary ◽  
Doubling Times

ABSTRACT In ovaries of immature rats the following parameters were estimated from autoradiographs prepared after pulse labelling with tritiated thymidine: 1) The time it takes follicles to grow from one stage of development to another. This could be derived from the total number of granulosa cells in these stages and from their doubling times. The doubling time of granulosa cells was determined from their labelling index and the duration of their DNA-synthesis phase. 2) The number of follicles present in the ovary at different ages. 3) The number of follicles, which start on their development at different ages. It was found, that more follicles start to grow in 8 and 16 days old rats (2.0/h) than in 28 days old ones (1.0/h). Moreover, the follicles grow somewhat faster earlier in life than later. The development from a follicle with one layer of granulosa cells to one with several layers and antrum formation takes about 15 days in the first half of the period of immaturity while it takes about 17 days as the animal approaches maturity.

scholarly journals Vasoactive intestinal polypeptide in the PMSG-primed immature rat ovary and its effect on ovulation in the isolated rat ovary perfused in vitro

Reproduction ◽  
1990 ◽  
Vol 90 (2) ◽  
pp. 465-472 ◽  
Author(s):  
G. Schmidt ◽  
J. Jorgensen ◽  
P. Kannisto ◽  
F. Liedberg ◽  
B. Ottesen ◽  
...  
Keyword(s):  
Vasoactive Intestinal Polypeptide ◽  
Immature Rat ◽  
Rat Ovary ◽  
Isolated Rat ◽  
Intestinal Polypeptide

THE RESPONSE OF THE IMMATURE RAT OVARY TO GONADOTROPHINS: ACUTE CHANGES IN CYCLIC AMP, PROGESTERONE, TESTOSTERONE, ANDROSTENEDIONE AND OESTRADIOL AFTER TREATMENT WITH PMS OR FSH + LH

1976 ◽  
Vol 82 (2) ◽  
pp. 413-425 ◽  
Author(s):  
T. Sashida ◽  
D. C. Johnson
Keyword(s):  
Cyclic Amp ◽  
Control Level ◽  
Elevated Serum ◽  
Serum Testosterone ◽  
Female Rats ◽  
Serum Testosterone Level ◽  
Base Line ◽  
Serum Progesterone ◽  
Immature Rat ◽  
Rat Ovary

ABSTRACT Radioimmunoassays were used to measure changes in progesterone, testosterone, androstenedione, oestradiol, gonadotrophin and ovarian cyclic AMP in immature female rats during the first 24 h after exposure to slowly (PMS) or rapidly (FSH + LH) disappearing gonadotrophins. Cyclic AMP was increased 30 min after injection of either kind of gonadotrophin but it had returned to control level within 4 h. Serum and ovarian testosterone and androstenedione also increased to a peak at 30 min but decreased to base line by the 4th h. Multiple injections of FSH + LH maintained an elevated serum testosterone level but they had little effect upon the secretion of androstenedione. Serum and ovarian progesterone increased quickly after treatment with gonadotrophin. With PMS the peak in the serum was reached at 8 h, it remained high for 4 h and then fell precipitously between the 12th and 16th h. FSH + LH produced a prompt increase in serum progesterone but the level could be maintained only by repeated doses given every 4 h. Oestradiol was not increased in the serum or the ovary until 20 h after PMS. One or two doses of FSH + LH did not produce an increase in oestrogen but a transient increase was found with 3 doses; 4 doses kept an elevated level of oestradiol for 12 h. These results indicate that the aromatizing system of the immature rat ovary is relatively inactive and that continual stimulation by gonadotrophin for about 10–12 h is necessary to bring about increased function. In contrast, the mechanisms for the synthesis and secretion of progesterone and androgens are very active and can be immediately stimulated by exposure to gonadotrophins.

scholarly journals Rainbow trout hypocalcin stimulates bone resorption in embryonic mouse calvaria in vitro in a PTH-like fashion

1989 ◽  
Vol 143 (1) ◽  
pp. 165-175
Author(s):  
F. P. Lafeber ◽  
M. P. Herrmann-Erlee ◽  
G. Flik ◽  
S. E. Wendelaar Bonga
Keyword(s):  
Bone Resorption ◽  
Cyclic Amp ◽  
Tertiary Structure ◽  
Lactate Production ◽  
Dependent Manner ◽  
Embryonic Mouse ◽  
Molar Basis ◽  
Mouse Calvaria ◽  
Dose Dependent

Hypocalcin, the major hormone with hypocalcaemic action in fish, was isolated from trout corpuscles of Stannius (SCs). The bioactivity of hypocalcin was assessed in a parathyroid hormone (PTH) bioassay involving bone resorption in embryonic mouse calvaria. Calcium and phosphate release and lactate production were stimulated in a dose-dependent manner by hypocalcin. On a molar basis about equal amounts of hypocalcin and PTH were required to obtain similar effects in this assay. Hypocalcin did not stimulate cyclic AMP production either in mouse calvaria or in cultured osteoblasts. In this respect hypocalcin resembles shortened or N-terminus-modified PTH molecules that induce bone resorption without increasing cyclic AMP levels. Since hypocalcin and PTH have comparable bioactivity in this mammalian bioassay (as well as in fish bioassays), we tentatively suggest that both hormones are structurally similar and that both hormones may act via the same receptors. The two hormones show no resemblance to one another in primary structure, so we suggest that they have similarities in tertiary structure.

AGE-RELATED CHANGES IN THE METABOLISM OF [3H]TESTOSTERONE IN VITRO BY THE EPIDIDYMIS OF THE IMMATURE RAT

1981 ◽  
Vol 91 (1) ◽  
pp. 43-51 ◽  
Author(s):  
R. G. FOLDESY ◽  
J. H. LEATHEM
Keyword(s):  
Adult Rats ◽  
Testosterone Metabolism ◽  
Pubertal Maturation ◽  
Immature Rat ◽  
Age Related ◽  
Rat Epididymis ◽  
Old Rats ◽  
Prepubertal Rats ◽  
Cauda Epididymidis

We examined the production in vitro of 5α-reduced metabolites from testosterone by the rat epididymis during pubertal maturation. Minced caput and cauda epididymides from 30-, 45-, and 55-day-old rats were incubated with [3H]testosterone for 2 h. Analysis of the radioactive metabolites revealed both similarities and differences in the metabolic patterns compared to those reported for adult rats. As in adults, 5α-dihydrotestosterone was the most abundant metabolite produced by both epididymal segments at all three ages, and it was formed in larger quantities in the caput epididymidis than in the cauda. However, [3H]testosterone metabolism by the epididymis of the immature rat was characterized by a lower formation of 5α-androstane-3α,17β-diol and higher production of 5α-androstane-3,17-dione than in adults. Production of these two metabolites by the caput region increased and decreased respectively, toward adult levels, with increasing age. In addition, the amount of [3H]testosterone metabolized was higher with tissues from prepubertal rats (30 days of age) than with those from rats 55 days of age. These data suggest that testosterone metabolism in the caput begins to change to that of the adult during the period of pubertal maturation but apparently not until later in the cauda epididymidis.

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