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71.
Alexander V. Sirotkin Du?an Fabian Janka Babe?ová Radoslava Vl?ková Saleh Alwasel Abdel Halim Harrath 《Reproductive biology》2018,18(1):5-11
We investigated the effects of body fat content on mouse fecundity, ovarian hormone release, and their response to follicle stimulation hormone (FSH). 4 types of females were produced: lean (group 1), normal (group 2), slightly fat (group 3), and significantly fat (group 4). The body weights, fat content, fertility rate, embryo number produced, retarded and degenerated embryo percentage, the release of progesterone (P4), testosterone (T), and insulin-like growth factor I (IGF-I) by isolated ovaries cultured with and without FSH (1.0 IU/mL medium) were evaluated. A gradual increase in body weight and fat contents from groups 1 to 4 was observed. Group 2 had higher fertility rate than those from the other groups. Groups 2 and 3 had fewer retarded and degenerated embryos that those from groups 1 and 4. Embryo production rate was not different among the groups. P4 and T secretion was higher from group 4 than in those from groups 1–3; secretion of IGF-I of group 3 was less than that of groups 1, 2, and 4. FSH promoted ovarian T output in all groups and stimulated ovarian P4 release in groups 1, 3, and 4, but not in group 2. FSH did not affect IGF-I release in any group. Therefore, both malnutrition and overfeeding can affect body weight and fat content in female mice, reducing embryo quality or developmental capacity, but not fertility and embryo production. Excess weight or fat can have stimulatory effects on ovarian P4 and T, but inhibitory effects on ovarian IGF-I release. Both leanness and excess weight or fat can induce the stimulatory action of FSH on ovarian P4. 相似文献
72.
用本室制备的兔抗羊促肾上腺皮质激素释放激素(CRH)多克隆抗体和 ̄(125)I标记的Tyr°-rCRH建立了CRH放射免疫测定法。并用该方法测定了人胎盘组织和大鼠脑及胸腺组织CRH含量。所得抗体与rCRH的亲合常数Ka=5.3×10 ̄9L/mol,与促肾上腺皮质激素、血管紧张素I、β-内啡肽、生长激素释放因子、血管活性肠肽、胆囊收缩素、加压素等18种肽没有交叉反应。 ̄(125)I-rCRH的比放射性为4163kBq/μg。建成的CRH放射免疫测定法取代比率为2.29,灵敏度为40pg,ED_(50)约为650pg,百分精密度和百分准确度分别为3.84%和10.36%。用该法所测人胎盘和大鼠组织CRH含量的结果表明,分娩胎盘组织CRH含量远高于妊娠6─7周者,约相当于后者的15倍;大鼠组织CRH含量以下丘脑最高,垂体次之,然后依次是海马、胸腺和大脑皮质;且下丘脑和垂体的CRH含量雄鼠明显高于雌鼠。 相似文献
73.
A highly specific and sensitive radioimmunoassay (RIA) for a novel porcine brain natriuretic peptide (BNP) has been established to elucidate whether BNP-like immunoreactivity (LI) is present in human plasma. The antibody used was specific for BNP without any crossreactivities with known human atrial natriuretic peptides (hANP). After extraction of human plasma with Sep-Pak cartridge, this assay allowed for detection of BNP-LI as low as 0.1 fmol/tube. In 12 healthy subjects, the mean concentrations of plasma BNP-LI were 1.5 fmol/ml. Reverse-phase HPLC coupled with BNP RIA revealed that the single major component with BNP-LI, corresponding to porcine BNP(1–26), was apparently distinct from that of -hANP. These data indicate that a small molecular mass form with BNP-LI circulates in human blood. 相似文献
74.
K L Clay R C Murphy J L Andres J Lynch P M Henson 《Biochemical and biophysical research communications》1984,121(3):815-825
Platelet activating factor (PAF) synthesized by human neutrophils challenged by opsonized zymosan or calcium ionophore was isolated from cells and buffer using Bligh and Dyer extraction following the addition of tracer amounts of tritiated-PAF. The extract was subjected to TLC separation of phospholipid classes, followed by reverse phase HPLC for molecular species separation. All fractions were measured for radioactivity, biological activity and fast atom bombardment mass spectrometry. While the radioactive tracer PAF could be separated into three molecular species, PAF biological activity eluted as a single component which was characterized as 1-O-hexadecyl-2-acetyl-glycero-3-phosphocholine. The lack of molecular species heterogeneity of PAF produced in response to stimuli implies a higher degree of control of biosynthesis than previously suspected. 相似文献
75.
Chemical characterization of the two forms of epidermal growth factor in murine saliva 总被引:2,自引:0,他引:2
Petro E. Petrides Peter Böhlen John E. Shively 《Biochemical and biophysical research communications》1984,125(1):218-228
Extracts of murine salivary glands contain two molecular forms of epidermal growth factor, EGF I and EGF II (Petrides, P.E., Levine, A.E., Shooter, E.M. in: Peptides: - Synthesis, Structure and Function (Rich, D.H., Gross, E.eds.) p. 781 (1981]. We have identified both molecules not only in salivary gland extracts but also in saliva using only reverse phase liquid chromatography methodology. EGF I and II were isolated from submaxillary gland extracts in a ratio of 3:1 regardless of whether the classical isolation procedure or our rapid RPLC based technique was used. Both molecular forms were present in the same ratio in saliva of mice of both sexes when salivation was induced by epinephrine treatment of the animals. As judged by amino acid analysis and N-terminal sequencing salivary EGF I corresponds to the 53 amino acid sequence of murine EGF and EGF II is Des-ASN-EGF. The observation that EGF and Des-ASN-EGF are consecreted into saliva upon epinephrine stimulation implies a physiological role of EGF II which may be related to the high molecular weight EGF-complex. 相似文献
76.
Naoto Minamino Hiroshi Masuda Kenji Kangawa Hisayuki Matsuo 《Biochemical and biophysical research communications》1984,124(3):731-738
Neuromedin K and neuromedin L are novel mammalian tachykinins isolated from porcine spinal cord. We have developed a highly sensitive radioimmunoassay for neuromedin K. Since the radioimmunoassay for neuromedin K has significant crossreactivity with neuromedin L and substance P, we can simultaneously determine the tissue concentrations of neuromedin K, neuromedin L and substance P after separation of the tissue extracts by reverse phase high performance liquid chromatography. Substance P is found to be the most abundant mammalian tachykinin in every brain region. The ratio of the concentration of substance P to neuromedin K is small in cerebral cortex and large in medulla-pons, while that of substance P to neuromedin L is rather constant in a range of 2.0–2.5. In spinal cord, dorsal half contains more neuromedin K and L than ventral half as is the case with substance P. These results indicate that both neuromedin K and L are endogenous mammalian tachykinins with specific physiological functions. 相似文献
77.
78.
The properties of transposon Tn5 that render it useful for in vivo mutagenesis of cloned DNA sequences are reviewed. Transposition frequency, insertional specificity, polarity and stability of Tn5 insertion mutations are among the topics discussed. Examples are cited from the published literature which illustrate the applications of Tn5 mutagenesis to the analysis of cloned prokaryotic and eukaryotic genes. A methods section is included which outlines precisely how to carry out transposon Tn5 mutagenesis analysis of cloned DNA segments. 相似文献
79.
Maria Lúcia Bonfleur Emerielle Cristine Vanzela Rosane Aparecida Ribeiro Gabriel de Gabriel Dorighello Carolina Prado de França Carvalho Carla Beatriz Collares-Buzato Everardo Magalhães Carneiro Antonio Carlos Boschero Helena Coutinho Franco de Oliveira 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2010,1801(2):183-190
We investigated whether primary hypercholesterolaemia per se affects glucose homeostasis and insulin secretion in low-density lipoprotein receptor knockout mice (LDLR−/−). Glucose plasma levels were increased and insulin decreased in LDLR−/− compared to the wild-type mice. LDLR−/− mice presented impaired glucose tolerance, but normal whole body insulin sensitivity. The dose–response curve of glucose-stimulated insulin secretion was shifted to the right in LDLR−/− islets. Significant reductions in insulin secretion in response to l-leucine or 2-ketoisocaproic acid were also observed in LDLR−/−. Islet morphometric parameters, total insulin and DNA content were similar in both groups. Glucose uptake and oxidation were reduced in LDLR−/− islets. Removal of cholesterol from LDLR−/− islets corrected glucose-stimulated insulin secretion. These results indicate that enhanced membrane cholesterol content due to hypercholesterolaemia leads to a lower insulin secretion and glucose intolerance without affecting body insulin sensitivity. This represents an additional risk factor for diabetes and atherosclerosis in primary hypercholesterolaemia. 相似文献
80.
Our previous studies showed that the prothoracicotropic hormone (PTTH) stimulated extracellular signal-regulated kinase (ERK) phosphorylation in prothoracic glands of Bombyx mori both in vitro and in vivo. In the present study, the signaling pathway by which PTTH activates ERK phosphorylation was further investigated using PTTH, second messenger analogs, and various inhibitors. ERK phosphorylation induced by PTTH was partially reduced in Ca2+-free medium. The calmodulin antagonist, calmidazolium, partially inhibited both PTTH-stimulated ERK phosphorylation and ecdysteroidogenesis, indicating the involvement of calmodulin. When the prothoracic glands were treated with agents that directly elevate the intracellular Ca2+ concentration [either A23187, thapsigargin, or the protein kinase C (PKC) activator, phorbol 12-myristate acetate (PMA)], a great increase in ERK phosphorylation was observed. In addition, it was found that PTTH-stimulated ecdysteroidogenesis was greatly attenuated by treatment with PKC inhibitors (either calphostin C or chelerythrine C). However, PTTH-stimulated ERK phosphorylation was not attenuated by the above PKC inhibitors, indicating that PKC is not involved in PTTH-stimulated ERK phosphorylation. A potent and specific inhibitor of insulin receptor tyrosine kinase, HNMPA-(AM)3, greatly inhibited the ability of PTTH to activate ERK phosphorylation and stimulate ecdysteroidogenesis. However, genistein, another tyrosine kinase inhibitor, did not inhibit PTTH-stimulated ERK phosphorylation, although it did markedly attenuate the ability of A23187 to activate ERK phosphorylation. From these results, it is suggested that PTTH-stimulated ERK phosphorylation is only partially Ca2+- and calmodulin-dependent and that HNMPA-(AM)3-sensitive receptor tyrosine kinase is involved in activation of ERK phosphorylation by PTTH. 相似文献