STUDIES ON THE MECHANISM OF SECRETION OF CORTICOSTEROIDS BY THE ISOLATED PERFUSED ADRENAL OF THE RAT

1981 ◽  
Vol 91 (2) ◽  
pp. 313-323 ◽  
Author(s):  
C. P. SIBLEY ◽  
B. J. WHITEHOUSE ◽  
G. P. VINSON ◽  
C. GODDARD ◽  
E. McCREDIE
Keyword(s):  
Culture Medium ◽  
Ion Concentration ◽  
Acth Stimulation ◽  
Steroid Production ◽  
Simple Diffusion ◽  
Corticosterone Secretion ◽  
Complex Process ◽  
Doc Production ◽  
Different Levels

A technique for the perfusion of the rat adrenal cortex is described. With tissue culture Medium 199 the preparation was responsive in terms of steroid production to both ACTH and K+ ions. Production of corticosterone and 18-hydroxydeoxycorticosterone (18-hydroxy-DOC) was stimulated by ACTH when it was administered at rates between 5 μu./min and 5 mu./min. Increasing the K+ ion concentration of the perfusate from 3·6 to 5·4 and 8·9 mmol/l stimulated the production of aldosterone, 18-hydroxycorticosterone and deoxycorticosterone, although not of corticosterone or 18-hydroxy-DOC. This preparation has been used to study further the mechanism of secretion of corticosterone and 18-hydroxy-DOC. Thus, production of these two steroids was measured at different perfusion flows, varying between 0·1 and 0·6 ml/min, with different levels of ACTH stimulation. Corticosterone production was significantly (P < 0·001) increased by increasing flows both under control conditions and when ACTH was administered at constant rates of 50 μu./min or 1 mu./min. Production of 18-hydroxy-DOC was not affected by flow either under control conditions or with 50 μu. ACTH/min. However, when ACTH was administered at 1 mu./min, 18-hydroxy-DOC production was also significantly (P < 0·001) increased by flow. The results are consistent with those obtained in previous in-vitro studies and have been interpreted as suggesting that the main mechanism of corticosterone secretion is simple diffusion. In contrast, 18-hydroxy-DOC secretion, at least at sub-maximal levels of stimulation, appears to require a more complex process.

In vitro development rate of preimplantation rabbit embryos cultured with different levels of melatonin

Zygote ◽  
2013 ◽  
Vol 23 (1) ◽  
pp. 111-115 ◽  
Author(s):  
Gamal Mohamed Kamel Mehaisen ◽  
Ayman Moustafa Saeed
Keyword(s):  
Culture Medium ◽  
Control Culture ◽  
M 10 ◽  
Morula Stage ◽  
High Level ◽  
Vitro Development ◽  
And Control ◽  
Different Levels ◽  
Rabbit Embryos

SummaryThis study aimed to investigate the effect of melatonin supplementation at different levels in culture medium on embryo development in rabbits. Embryos of 2–4 cells, 8–16 cells and morula stages were recovered from nulliparous Red Baladi rabbit does by laparotomy technique 24, 48 and 72 h post-insemination, respectively. Normal embryos from each stage were cultured to hatched blastocyst stages in either control culture medium (TCM-199 + 20% fetal bovine serum) or control supplemented with melatonin at 10−3 M, 10−6 M or 10−9 M. No effect of melatonin was found on development of embryos recovered at 24 h post-insemination. The high level of melatonin at 10−3 M adversely affected the in vitro development rates of embryos recovered at 48 h post-insemination (52 versus 86, 87 and 80% blastocyst rate; 28 versus 66, 78 and 59% hatchability rate for 10−3 M versus 10−9 M, 10−6 M and control, respectively, P< 0.05). At the morula stage, melatonin at 10−3 M significantly increased the in vitro development of embryos (92% for 10−3 M versus 76% for control, P < 0.05), while the hatchability rate of these embryos was not improved by melatonin (16–30% versus 52% for melatonin groups versus control, P < 0.05). Results show that a moderate level of melatonin (10−6 M) may improve the development and hatchability rates of preimplantation rabbit embryos. The addition of melatonin at a 10−3 M concentration enhances the development of rabbit morulae but may negatively affect the development of earlier embryos. More studies are needed to optimize the use of melatonin in in vitro embryo culture in rabbits.

Do novel cement-type biomaterials reveal ion reactivity that affects cell viability in vitro?

2014 ◽  
Vol 9 (3) ◽  
pp. 277-289 ◽  
Author(s):  
Agata Przekora ◽  
Joanna Czechowska ◽  
Dawid Pijocha ◽  
Anna Ślósarczyk ◽  
Grażyna Ginalska
Keyword(s):  
Culture Medium ◽  
Cultured Cells ◽  
Diffraction Method ◽  
Ion Concentration ◽  
Filler Materials ◽  
Cement Type ◽  
Ion Interactions ◽  
Surrounding Environment ◽  
Calcium Magnesium

AbstractCalcium phosphate bioceramics have been studied as bone filler materials for years and have become a component of many commercial products. It is widely known that surface-reactive biomaterials may cause changes in the concentration of crucial ions in the surrounding environment, thereby affecting cell metabolism and viability. The aim of this study was to produce five cement-type biomaterials and characterize their phase composition using X-ray diffraction method, and porosity and pore size distribution using mercury intrusion porosimeter. We then evaluated ion interactions of the novel biomaterials with the surrounding environment (culture medium). A commercially available bone substitute, HydroSet™ (Stryker®), was used as a reference. MTT and NRU cytotoxicity tests were performed to assess the effect of changes in the concentration of crucial ions (calcium, magnesium, phosphate) on osteoblast metabolism and viability in vitro. Our study clearly indicated that various biomaterials demonstrated different ion reactivity and consequently may cause changes in ion concentration in the local environment. Critically low or high values of calcium, magnesium, and phosphate concentrations in the medium exerted cytotoxic effects on the cultured cells. Moreover, we discovered that the chemical composition of the culture medium had a substantial influence on ion interactions with biomaterials.

Relations entre hypolignification et état vitreux chez Salix babylonica en culture in vitro. Rôle de la nutrition ammoniacale

1985 ◽  
Vol 63 (2) ◽  
pp. 324-326 ◽  
Author(s):  
F. Daguin ◽  
R. Letouze
Keyword(s):  
Culture Medium ◽  
Culture Media ◽  
Lignin Content ◽  
Nitrogen Supply ◽  
Xylem Tissue ◽  
Basal Media ◽  
Salix Babylonica ◽  
The Relationship ◽  
Different Levels

The relationship between nitrogen-fed willow cuttings cultured in vitro and the appearance of vitreous plants has been studied. By using two basal media (Murashige and Skoog medium and Knop medium half diluted) an in vitro culture scheme has been developed which allows the control of the vitrification process by varying the nitrogen supply in the culture media. The results obtained agree that the vitrification of the cloned plants is directly associated with the ammonium content of the culture medium. In vitrified plants, lignin content of the shoot is reduced by 50%. Correlatively, histological controls at different levels of the shoot of the plantlets show that the reduction of the xylem tissue can reach 70%.

Steroid production in vitro by rat ovaries during sexual maturation

1983 ◽  
Vol 99 (3) ◽  
pp. 469-475 ◽  
Author(s):  
J. Th. J. Uilenbroek ◽  
P. J. A. Woutersen ◽  
R. van der Linden
Keyword(s):  
Sexual Maturation ◽  
Culture Medium ◽  
Reductase Activity ◽  
Maximal Response ◽  
Steroid Production ◽  
Age Related ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Oestradiol Production

To determine changes in steroidogenesis by rat ovaries during sexual maturation, ovaries obtained at various ages (days 10–35) and at the first pro-oestrus were incubated in the absence or presence of LH and the accumulation of steroids in the medium was measured. Basal and LH-stimulated oestradiol-17β and testosterone release into the medium, expressed in pmol/4 h per mg ovary, was high at day 10 of age and at first pro-oestrus. Between days 20 and 35 basal oestradiol and testosterone release was low and could not be stimulated by LH. Addition of testosterone to the culture medium increased oestradiol production at all ages studied. Release of progesterone occurred at all ages even in LH-free medium. Incubation in the presence of LH resulted in a dose-dependent increase in progesterone with a maximal response at pro-oestrus. Androsterone and 5α-androstane-3α,17β-diol production in the absence or presence of LH was high during the entire prepuberal period. Production of 5α-reduced androgens in response to LH increased from days 10 to 20 but decreased thereafter. Similarly, 5α-reductase activity, measured in ovarian homogenates, increased from days 10 to 20 but was decreased again by first pro-oestrus. A further decrease in basal and LH-stimulated 5α-reduced androgen production occurred after first ovulation. These results demonstrated age-related changes in steroid release after in-vitro incubation. At day 10 progesterone can be converted to aromatizable androgens allowing production of oestrogens, while after day 10 progesterone is converted to 5α-reduced C19 steroids. The decrease in 5α-reductase activity correlates with an increase in LH-stimulated testosterone and oestradiol production at the first pro-oestrus.

scholarly journals Impact of various endocrine and paracrine factors on in vitro culture of preantral follicles in rodents

Reproduction ◽  
2005 ◽  
Vol 130 (2) ◽  
pp. 147-156 ◽  
Author(s):  
I Demeestere ◽  
J Centner ◽  
C Gervy ◽  
Y Englert ◽  
A Delbaere
Keyword(s):  
Oocyte Maturation ◽  
Culture Medium ◽  
Follicular Growth ◽  
Medium Effects ◽  
Paracrine Factors ◽  
Autocrine Factors ◽  
Preantral Follicles ◽  
Whole Process ◽  
Complex Process

Folliculogenesis is a complex process regulated by various paracrine and autocrine factors. In vitro growth systems of primordial and preantral follicles have been developed for future use of immature oocytes, as sources of fertilizable oocytes and for studying follicular growth and oocyte maturation mechanisms. Rodents were often chosen for in vitro follicular culture research and a lot of factors implicated in folliculogenesis have been identified using this model. To date, the mouse is the only species in which the whole process of follicular growth, oocyte maturation, fertilization and embryo transfer into recipient females was successfully performed. However, the efficiency of in vitro culture systems must still be considerably improved. Within the follicle, numerous events affect cell proliferation and the acquisition of oocyte developmental competency in vitro, including interactions between the follicular cells and the oocyte, and the composition of the culture medium. Effects of the acting factors depend on the stage of follicle development, the culture system used and the species. This paper reviews the action of endocrine, paracrine factors and other components of culture medium on in vitro growth of preantral follicles in rodents.

Serotoninergic regulation of corticosterone secretion in domestic fowl

1987 ◽  
Vol 113 (2) ◽  
pp. 159-165 ◽  
Author(s):  
A. Cheung ◽  
T. R. Hall ◽  
S. Harvey
Keyword(s):  
Domestic Fowl ◽  
Serotonin Receptor ◽  
Plasma Concentrations ◽  
Adrenocortical Function ◽  
Serotoninergic System ◽  
Acth Stimulation ◽  
Corticosterone Secretion ◽  
Corticosterone Release ◽  
Adrenal Corticosterone

ABSTRACT The effects of serotoninergic drugs on adrenocortical function in domestic fowl were examined. Administration of the serotonin receptor agonist 2-(1-piperazinyl)quinoline maleate (quipazine), an inhibitor of serotonin metabolism, N-methyl-N-2-propynylbenzylamine HCl (pargyline), as well as serotonin itself, all increased plasma concentrations of corticosterone. The maximum responses to serotonin and quipazine occurred 1 h after treatment. The quipazine-stimulated response was partly prevented by the serotonin antagonist cyproheptadine. Cockerels pretreated with dexamethasone, a synthetic steroid known to inhibit pituitary ACTH release, showed attenuated responses to subsequent quipazine, pargyline or serotonin injection. Serotonin, quipazine and cyproheptadine did not affect corticosterone release directly from the adrenal gland incubated in vitro, nor did they affect adrenal responsiveness to ACTH stimulation. The neurotoxin 5,6-dihydroxytryptamine injected into day-old chicks decreased plasma concentrations of corticosterone for up to 7 days after treatment, with corresponding decreases in the hypothalamic concentration of serotonin, but not dopamine or noradrenaline concentrations. These results show that adrenal corticosterone secretion is regulated by a central serotoninergic system, probably acting on the hypothalamo-pituitary-adrenal axis. J. Endocr. (1987) 113,159–165

Immunoenzymatic demonstration of the simultaneous presence of transferrin, hemopexin and albumin in a same hepatocyte and their ultrastructural localization

1978 ◽  
Vol 36 (2) ◽  
pp. 88-89
Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau
Keyword(s):  
Plasma Proteins ◽  
Rat Hepatocytes ◽  
Ultrastructural Localization ◽  
Carrier Proteins ◽  
Normal Cells ◽  
Adult Rat ◽  
Adult Rat Hepatocytes ◽  
Monospecific Antisera ◽  
Different Levels

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.

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+.

Pulsatile GnRH secretion from primary cultures of sheep olfactory placode explants

Reproduction ◽  
2000 ◽  
pp. 391-396 ◽  
Author(s):  
AH Duittoz ◽  
M Batailler
Keyword(s):  
Culture Medium ◽  
Primary Cultures ◽  
Pulsatile Secretion ◽  
Olfactory Placode ◽  
Gnrh Secretion ◽  
Individual Culture ◽  
Pulsatile Gnrh

The aim of this study was to investigate the development of pulsatile GnRH secretion by GnRH neurones in primary cultures of olfactory placodes from ovine embryos. Culture medium was collected every 10 min for 8 h to detect pulsatile secretion. In the first experiment, pulsatile secretion was studied in two different sets of cultures after 17 and 24 days in vitro. In the second experiment, a set of cultures was tested after 10, 17 and 24 days in vitro to investigate the development of pulsatile GnRH secretion in each individual culture. This study demonstrated that (i) primary cultures of GnRH neurones from olfactory explants secreted GnRH in a pulsatile manner and that the frequency and mean interpulse duration were similar to those reported in castrated ewes, and (ii) pulsatile secretion was not present at the beginning of the culture but was observed between 17 and 24 days in vitro, indicating the maturation of individual neurones and the development of their synchronization.

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