scholarly journals Experimental modification of rat pituitary prolactin cell function during and after spaceflight

1996 ◽  
Vol 80 (3) ◽  
pp. 971-980 ◽  
Author(s):  
W. C. Hymer ◽  
T. Salada ◽  
L. Avery ◽  
R. E. Grindeland
Keyword(s):  
Posttranslational Modifications ◽  
Cell Function ◽  
Biological Activities ◽  
Male Rat ◽  
Molecular Weights ◽  
Significant Difference ◽  
Rat Pituitary ◽  
Cellular And Humoral Immunity ◽  
Pituitary Prolactin

This study was done to evaluate the effects of microgravity on prolactin (PRL) cells of the male rat pituitary gland. We used the identical passive closed-vial cell culture system that was described for the culture of growth hormone cells (W. C. Hymen, R. E. Grindeland, T. Salada, P. Nye, E. Grossman, and P. Lane. J. Appl. Physiol. 80:955-970, 1996). After an 8-day spaceflight, all flight media (containing released PRL), as well as extracts (containing intracellular PRL), contained significantly lower amounts of immunoreactive PRL than their corresponding ground control samples. On the other hand, these same samples, when assessed for their biological activities by two different in vitro lymphocyte assays, yielded disparate results that may reflect posttranslational modifications to the hormone molecule. Other data showed that 1) the apparent molecular weights of released PRL molecules were not altered by microgravity, but 2) the region from which the PRL cells came (dorsal or ventral) made a significant difference in the amount and activity of PRL released from the flight cells. Because there is much current interest in the role that PRL may play in the regulation of the immune system and because changes in both cellular and humoral immunity accompany spaceflight, this study could help define future microgravity research in this area.

ONSET OF OESTROGEN-INDUCED PROLACTIN SECRETION AND DNA SYNTHESIS BY THE RAT PITUITARY GLAND

1977 ◽  
Vol 72 (1) ◽  
pp. 35-39 ◽  
Author(s):  
JOAN JACOBI ◽  
H. M. LLOYD ◽  
J. D. MEARES
Keyword(s):  
Dna Synthesis ◽  
Pituitary Gland ◽  
Prolactin Secretion ◽  
Male Rat ◽  
Serum Prolactin ◽  
Rat Pituitary ◽  
The Times ◽  
Pituitary Prolactin

SUMMARY The times of onset of oestrogen-induced prolactin secretion and DNA synthesis were studied in the pituitary gland of the male rat. At intervals from 3 to 96 h after injection of 10 mg diethylstilboestrol dipropionate, serum and pituitary prolactin concentrations were measured by radioimmunoassay and pituitary DNA synthesis by incorporation of [3H]thymidine in vitro. Serum prolactin was raised significantly from 6 h onwards and DNA synthesis was increased from 30 h onwards. Pituitary prolactin concentration began to increase at 30 h. Significant correlations were obtained between serum prolactin and DNA synthesis from 24 to 72 h but not during the period of prolactin secretion from 6 to 24 h.

In vitro metabolism of 3H-androstenedione by the male rat pituitary, hypothalamus, and hippocampus

Steroids ◽  
1975 ◽  
Vol 25 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Ana E. Pérez ◽  
Alfredo Ortíz ◽  
Marisa Cabeza ◽  
Carlos Beyer ◽  
Gregorio Pérez-Palacios
Keyword(s):  
In Vitro Metabolism ◽  
Male Rat ◽  
Rat Pituitary

scholarly journals Size-controlled human adipose-derived stem cell spheroids hybridized with single-segmented nanofibers and their effect on viability and stem cell differentiation

2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Jinkyu Lee ◽  
Sangmin Lee ◽  
Sung Min Kim ◽  
Heungsoo Shin
Keyword(s):  
Stem Cell ◽  
Cell Function ◽  
Average Length ◽  
Three Dimensional ◽  
Stem Cell Differentiation ◽  
Cell Spheroids ◽  
Significant Difference ◽  
Vitro Analysis ◽  
Physical And Chemical

Abstract Background Fabrication of three-dimensional stem cell spheroids have been studied to improve stem cell function, but the hypoxic core and limited penetration of nutrients and signaling cues to the interior of the spheroid were challenges. The incorporation of polymers such as silica and gelatin in spheroids resulted in relatively relaxed assembly of composite spheroids, and enhancing transport of nutrient and biological gas. However, because of the low surface area between cells and since the polymers were heterogeneously distributed throughout the spheroid, these polymers cannot increase the cell to extracellular matrix interactions needed to support differentiation. Methods We developed the stem cell spheroids that incorporate poly(ι-lactic acid) single-segmented fibers synthesized by electrospinning and physical and chemical fragmentation. The proper mixing ratio was 2000 cells/μg fibers (average length of the fibers was 50 μm - 100 μm). The SFs were coated with polydopamine to increase cell binding affinity and to synthesize various-sized spheroids. The function of spheroids was investigated by in vitro analysis depending on their sizes. For statistical analysis, Graphpad Prism 5 software (San Diego, CA, USA) was used to perform one-way analysis of variance ANOVA with Tukey’s honest significant difference test and a Student’s t-test (for two variables) (P < 0.05). Results Spheroids of different sizes were created by modulating the amount of cells and fibers (0.063 mm2–0.322 mm2). The fibers in the spheroid were homogenously distributed and increased cell viability, while cell-only spheroids showed a loss of DNA contents, internal degradation, and many apoptotic signals. Furthermore, we investigated stemness and various functions of various-sized fiber-incorporated spheroids. In conclusion, the spheroid with the largest size showed the greatest release of angiogenic factors (released VEGF: 0.111 ± 0.004 pg/ng DNA), while the smallest size showed greater effects of osteogenic differentiation (mineralized calcium: 18.099 ± 0.271 ng/ng DNA). Conclusion The spheroids incorporating polydopamine coated single-segmented fibers showed enhanced viability regardless of sizes and increased their functionality by regulating the size of spheroids which may be used for various tissue reconstruction and therapeutic applications.

401. In vitro metabolism of 3H-androstenedione by the male rat pituitary, hypothalamus, and hippocampus

1974 ◽  
Vol 5 (4) ◽  
pp. 391
Author(s):  
A.E. Perez ◽  
A. Ortiz ◽  
M. Cabeza ◽  
C. Beyer ◽  
G. Perez-Palacios
Keyword(s):  
In Vitro Metabolism ◽  
Male Rat ◽  
Rat Pituitary

Effect of starvation on gonadotrophin secretion and on in vitro release of LRH from the isolated median eminence of the male rat

1983 ◽  
Vol 103 (3) ◽  
pp. 293-301 ◽  
Author(s):  
Michael Warnhoff ◽  
Gunter Dorsch ◽  
Karl M. Pirke
Keyword(s):  
In Vitro Release ◽  
Basic Mechanism ◽  
Male Rat ◽  
Gonadotrophin Secretion ◽  
Significant Difference ◽  
Lh Release ◽  
And Control ◽  
Vitro Release

Abstract. A perfusion system was developed in which isolated median eminences (ME) were stimulated in vitro by depolarizing agents such as potassium and veratridine. Potassium concentrations between 30 and 80 mm released increasing amounts of luteinizing hormone-releasing hormone (LRH) from the MEs of starved and control rats. Veratridine at a concentration of 50 μm caused a more prolonged LRH release in both starved and control animals. LRH secretion in vitro was slightly, though not under all conditions, significantly greater in rats starved for 5 days. The testosterone (T)-LH feedback was studied by castrating the animals and substituting various doses of T through implantation of T-releasing capsules of different sizes. The concentration in plasma, which can prevent the castration-induced much smaller in starved than in control rats. The in vitro release of LRH evoked by 80 mm potassium was not different for starved and fed rats under various feedback conditions. Both groups revealed decreased in vitro release of LRH when castrated animals were not substituted with T. The effect of castration was studied from 1 to 28 days. The plasma LH values rapidly increased in starved and control animals, indicating that the hypothalamic responsestration is not delayed by starvation. The release in vitro of LRH decreased from the first to the fifth day and remained constant thereafter. No significant difference between starved and fed rats was observed. The experiments indicate that the 'releasable pool' of LRH in vitro is greater under conditions of reduced LH release in vivo. The basic mechanism of depolarization-induced exocytosis of LRH from the ME is intact in starved animals.

2-HYDROXYOESTRADIOL INHIBITS PROLACTIN RELEASE FROM THE SUPERFUSED RAT PITUITARY GLAND

1981 ◽  
Vol 90 (3) ◽  
pp. 315-322 ◽  
Author(s):  
ELIZABETH A. LINTON ◽  
NICKI WHITE ◽  
OFELIA LIRA DE TINEO ◽  
S. L. JEFFCOATE
Keyword(s):  
Pituitary Gland ◽  
Prolactin Secretion ◽  
Male Rat ◽  
Prolactin Release ◽  
Rat Pituitary ◽  
Lh Release

The effects of 2-hydroxyoestradiol (2OH-OE2), dopamine, oestradiol-17β and 2OH-OE2 plus dopamine on prolactin and LH release from the male rat pituitary gland were examined in vitro. 2-Hydroxyoestradiol reduced prolactin secretion by 51% at 10−10 mol/l and by 34% at 10−7 mol/l, while oestradiol-17β had no effect at these doses. Dopamine alone (5 × 10−7 mol/l) decreased prolactin released by 58%, 2OH-OE2 plus dopamine produced a similar inhibition of 60%. No significant effect on LH release was observed throughout.

ESTIMATION OF PROLACTIN AND GROWTH HORMONE LEVELS BY POLYACRYLAMIDE DISC ELECTROPHORESIS

1969 ◽  
Vol 45 (2) ◽  
pp. 183-NP ◽  
Author(s):  
C. S. NICOLL ◽  
J. A. PARSONS ◽  
R. P. FIORINDO ◽  
C. W. NICHOLS
Keyword(s):  
Growth Hormone ◽  
Adult Male ◽  
Prolactin Secretion ◽  
Disc Electrophoresis ◽  
Male Rat ◽  
Rat Pituitary ◽  
Hypothalamic Tissue ◽  
Prolactin Content ◽  
High Degree

SUMMARY A procedure for estimating rat prolactin and growth hormone (somatotrophin, STH), by measuring the optical density of the electrophoretically isolated and stained hormone bands in polyacrylamide gel columns, is described and evaluated. A simple and inexpensive densitometer is also described. Prolactin levels in adenohypophyses and in medium from pituitary incubates were measured by electrophoresis-densitometry (ED) and by the pigeon crop-sac assay. The two methods showed a high degree of correlation. The validity of the ED method for estimating prolactin levels in adenohypophysial tissue and in incubation medium was demonstrated by comparing the prolactin content of adult male and female and of oestrogen-treated male glands and by experiments in vitro. The female pituitary contained about three times more prolactin than the male and the glands of oestrogen-treated males had levels about the same as those of females. It was also shown that the ED method could be used to demonstrate the inhibitory effects of extract of rat hypothalamic tissue on prolactin secretion in vitro by the rat pituitary. Levels of STH in adult male glands, as measured by this method, were comparable to results obtained by others using immunoassays. Propylthiouracil-induced hypothyroidism depressed the STH and prolactin levels in male rat pituitaries, in agreement with the observations of others. The stainability of the prolactin band in rat adenohypophyses was observed to decrease with time when the glands were stored on dry ice. No such change occurred in the staining characteristics of the STH band. Other aspects of the ED method are discussed, including its precision, efficiency, sensitivity, economy and utility.

scholarly journals The Influence of Elementary Silver Versus Titanium on Osteoblasts Behaviour In Vitro Using Human Osteosarcoma Cell Lines

Sarcoma ◽  
2007 ◽  
Vol 2007 ◽  
pp. 1-5 ◽  
Author(s):  
Jendrik Hardes ◽  
Arne Streitburger ◽  
Helmut Ahrens ◽  
Thomas Nusselt ◽  
Carsten Gebert ◽  
...  
Keyword(s):  
Cell Lines ◽  
Cell Function ◽  
Antimicrobial Effect ◽  
Proliferation Rate ◽  
Osteosarcoma Cell ◽  
Human Osteosarcoma ◽  
Significant Difference ◽  
Human Osteosarcoma Cell ◽  
Experimental Trials

Purpose. The antimicrobial effect of a silver-coated tumor endoprosthesis has been proven in clinical and experimental trials. However, in the literature there are no reports concerning the effect of elementary silver on osteoblast behaviour. Therefore, the prosthetic stem was not silver-coated because of concerns regarding a possible inhibition of the osseointegration. The aim of the present study was to investigate the effect of 5–25 mg of elementary silver in comparison to Ti-6Al-4V on human osteosarcoma cell lines (HOS- 58, SAOS).Methods. Cell viability was determined by measuring the MTT proliferation rate. Cell function was studied by measuring alkaline phosphatase (AP) activity and osteocalcine production.Results. In the HOS-58 cells, the AP activity was statistically significant(P<0.05)higher at a supplement of 5–10 mg of silver than of Ti-6 Al-4V at the same doses. For both cell lines, a supplement above 10 mg of silver resulted in a reduced AP activity in comparision to the Ti-6 Al-4V group, but a statistically significant difference(P<0.05)was observed at a dose of 25 mg for the SAOS cells only. At doses of 20–25 mg in the HOS-58 cells and 10–25 mg in the SAOS cells, the reduction of the proliferation rate by silver was statistically significant(P<0.05)compared to the Ti-6 Al-4V supplement.Discussion. In conclusion, elementary silver exhibits no cytotoxicity at low concentrations. In contrast, it seems to be superior to Ti-6 Al-4V concerning the stimulation of osteogenic maturation at these concentrations, whereas at higher doses it causes the known cytotoxic properties.

Antiproliferative effects of melatonin on the growth of rat pituitary prolactin-secreting tumor cells in vitro

2007 ◽  
Vol 42 (2) ◽  
pp. 172-179 ◽  
Author(s):  
Quan-Hui Yang ◽  
Jian-Ning Xu ◽  
Rong-Kun Xu ◽  
Shiu-Fun Pang
Keyword(s):  
Tumor Cells ◽  
Antiproliferative Effects ◽  
Rat Pituitary ◽  
Pituitary Prolactin
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