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61.
Przała J Gregoraszczuk EL Kotwica G Stefańczyk-Krzymowska S Ziecik AJ Blitek A Ptak A Rak A Wójtowicz A Kamiński T Siawrys G Smolińska N Franczak A Kurowicka B Oponowicz A Wasowska B Chłopek J Kowalczyk AE Kaczmarek MM Wacławik A 《Reproductive biology》2006,6(Z1):59-87
The paper summarizes results of a series of studies concerning luteolysis and early pregnancy in pigs. The involvement of the oxytocin (OT)/OT receptor system in the mechanism of corpus luteum (CL) protection during early pregnancy as well as the implication of luteinizing hormone (LH) in the endometrial prostaglandin (PG) release and synthesis are described. In addition, the role of leptin in the regulation of ovarian steroidogenesis and the expression of leptin and its receptor (OB-Rb) genes in hypothalamus, pituitary and reproductive tissues are reported. Moreover, a strong emphasis was placed on the mechanism of PGE2 participation in the local endocrine regulations of reproductive processes occurring in the utero-ovarian area as well as on the vascular endothelial growth factor (VEGF) ligand-receptor system in the ovary and uterus. 相似文献
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The effect of growth hormone (GH) on insulin-like growth factor I (IGF-I) secretion and the effects of GH and IGF-I on [(3)H] thymidine incorporation and estradiol (E2) secretion by theca interna (Tc) and granulosa cells (Gc) cultured alone and in coculture were studied in cultured porcine follicular cells, prepared from small (SF), medium (MF) and large (LF) preovulatory follicles. We demonstrated that both Tc and Gc secrete IGF-I and that GH had no effect on IGF-I secretion by Tc but, increased IGF-I secretion by Gc isolated from SF and cultured alone or in coculture. IGF-I stimulated secretion of E2 by all cells, except in Tc derived from SF in which the effect was not statistically significant. The only stimulatory effect of concurrent treatment with GH on E2 secretion was noted in Tc derived from MF. IGF-I increased the [(3)H] thymidine incorporation in all Tc cells but GH did not augment this effect. In Gc, IGF-I stimulated [(3)H] thymidine incorporation in cells derived from SF and MF but not from LF. GH had no stimulatory effect except on Gc derived from LF and grown alone. The highest stimulatory effect was observed in SF. This was smaller in MF and no effect was noted in LF. In conclusion, our work shows that both Gc and Tc are sites of IGF-I production and for the first time shows the stimulatory role of IGF-I in proliferation of Tc cells derived from all types of follicles and augmentation of E2 secretion in Tc derived from MF and LF. The promotion of the mitogenic activity in Tc by IGF-I during all stages of follicular development suggests an important role for theca cells in follicular growth. 相似文献
65.
The aim of the present study was to test the hypothesis that growth hormone (GH) and insulin-like growth factor-I (IGF-I) act at a local level to inhibit luteal cell apoptosis. Luteal cells collected from the corpora lutea at different stages of the luteal phase were cultured for 24 h in M 199 medium supplemented with 5% of calf serum to cause attachment cells to the plastic. After 24 h, the media were changed and various concentrations of GH (10, 100 or 200 ng/ml) or IGF-I (30, 50 or 100 ng/ml) were added to the culture medium. Twenty-four hours later, cells were fixed for morphological assessment of apoptotic cells utilising a Hoechst staining technique. To support morphological observations, measurements of caspase-3 activity in cultured porcine luteal cells were performed. Increased incidence of apoptotic bodies and caspase-3 activity accompanied luteal regression and was associated with a decreased progesterone (P4) secretion by luteal cells. GH stimulated P4 secretion by luteal cells collected from developing (ELP) and mature (MLP) corpora lutea but had no effect on its secretion by cells collected from regressing corpora lutea (LLP). Moreover, it had no effect on the incidence of apoptotic bodies in all types of corpora lutea. However, suppression of caspase-3 activity was observed with 100 and 200 ng of GH/ml in all types of corpora lutea. IGF-I had a stimulatory effect on P4 secretion by ELP and MLP, decreased the incidence of apoptotic bodies and suppressed caspase-3 activity in cultures treated with all doses used. In conclusion, our results indicate that both GH and IGF-1 trigger anti-apoptotic effects either indirectly, by increasing progesterone secretion, or directly, through the inhibition of caspase-3 activity and subsequent prevention of apoptotic body formation. 相似文献
66.
Leaf temperature of desert sand dune plants: perspectives on the adaptability of leaf morphology 总被引:1,自引:0,他引:1
The leaf temperature of six annual and six perennial plant species was monitored during spring and summer on a sand dune ecosystem in the delta Mediterranean coast of Egypt. During winter, leaves of all tested perennial species attained temperatures higher than the air temperature at night and shortly after sunrise, with maximum leaf–air temperature differences reaching up to 8°C. The lowest differences were less than 1°C. Around noon, the leaves of several species attained temperatures lower than that of the air whereas others showed higher temperatures. The opposite was true during summer, when leaf temperatures were lower than air temperature. The maximum leaf–air temperature differences occurred after midnight towards sunrise and reached up to 10°C. The lowest differences were found around noon and were of less than 5°C. The annual plant species have more pronounced variations than perennials in their leaf temperatures during the night and for most of the day. The leaves were heated or cooled a few degrees above or below the air temperature. The results are discussed in relation to the morphological characters of the leaves. The variation in leaf temperature at different times of the day was significantly related to leaf morphology, specific leaf area, thickness, volume, leaf area index and the surrounding environment. 相似文献
67.
S. Stokłosowa E. Gregoraszczuk E. Holečková J. Michl 《Experimental cell research》1981,131(2):430-435
Granulosa cells harvested from pro-estrous follicles of porcine ovary were grown in medium 199 supplemented with 0.4, 1 and 10% of growth-promoting calf serum proteins (GPP), and their multiplication and hormonal activity were compared with those of sister cultures carried in medium 199 supplemented with 10% calf serum. The medium containing the growth-promoting proteins was always superior to the whole-serum medium with regard to cell multiplication, activity of Δ5,3 hydroxysteroid dehydrogenase detected histochemically in the cells, and production of progesterone estimated by radioimmunoassay in the medium. It was inferior when it came to estrogen secretion in the beginning of the cultivation when calculated on a per cell basis. 相似文献
68.
Histochemical features of two different parts of the porcine Fallopian tube have been studied, with special reference to cyclic changes in the distribution of glycogen particles. Porcine Fallopian tubes were obtained from a local slaughterhouse. Slides were studied under light microscopy utilising histological and histochemical techniques. The most striking feature during the periovulatory stage of the estrus cycle was the occurrence of glycogen granules in the apical cytoplasm of epithelial cells in both the ampulla and isthmus of the Fallopian tubes. In the isthmus, cells containing numerous granules of polysaccharides aggregated into areas of different sizes were noted after ovulation. During the midluteal phase their number was minimal or were even absent. In the ampula typical extrusion of secretory granules and nuclei protruding into the tubal lumen was visible after ovulation. In the luteal phase a lot of nuclei protruded into the tubal lumen and some free in the lumen were noted. It is possible that glycogen in the preovulatory stage functions as a source of energy for ciliary movement and as a nourishment for the ovum. In the isthmus large number of aggregated glycogen particles was observed also after ovulation. In this stage of the cycle, numerous granules of polysaccharide aggregated in isthmus epithelium could be the major energy source for embriogenesis when the embryo travels down the Fallopian tubes, during the early cleavage stage. 相似文献
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70.
Leibovich H Raver N Herman A Gregoraszczuk EL Gootwine E Gertler A 《Protein expression and purification》2001,22(3):489-496
Recombinant bovine Ala-prolactin (PRL) (GenBank Accession No. V00112) in prokaryotic expression plasmid pMON3401 was mutated using a mutagenesis kit, to prepare plasmid encoding ovine PRL (oPRL) (GenBank Accession No. M27057) Escherichia coli cells transformed with this latter plasmid overexpressed large amounts of oPRL upon induction with nalidixic acid. The expressed protein, found in inclusion bodies, was refolded and purified to homogeneity on a Q-Sepharose column, yielding an electrophoretically pure fraction composed of over 98% monomeric protein of the expected molecular mass of approximately 23 kDa. The biological activity of the recombinant oPRL after proper renaturation was evidenced in vitro by its ability to stimulate proliferation of rat lymphoma Nb(2) cells possessing PRL receptors, to stimulate luciferase activity in HEK 293 cells transiently transfected with oPRL receptors, and to induce progesterone secretion in primary cultures of luteal cells obtained from midpregnant ewes. In contrast to ovine growth hormone or ovine placental lactogen, recombinant oPRL had no galactopoietic effect in lactating ewes. 相似文献