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1.
Summary To investigate whether the hypothalamus is involved in the cytodifferentiation of the anterior pituitary gland, rat foetuses were encephalectomized in utero on day 16 of pregnancy.Pituitary sections from encephalectomized and normal littermate foetuses were studied on day 21 with the immunofluorescence technique using antibodies and -MSH, anti -MSH, anti -(17–39) ACTH and anti -(1–24) ACTH. On day 16, only the anti -MSH revealed a few cells in the pars distalis but not in the pars intermedia. On the other hand, on day 21, the pituitary cells reacting with antibodies anti -MSH, anti -MSH and anti -(17–39) ACTH were as numerous in the encephalectomized foetuses as in the normal littermate foetuses. The cells revealed with the antibody anti -(1–24) ACTH were less numerous and less fluorescent in the pars distalis and intermedia of the hypophysis of the encephalectomized foetuses.On day 21, the adrenals of the encephalectomized foetuses were atrophied in comparison with those of the normal littermate foetuses but they were larger than on day 16.These data suggest that the cytodifferentiation of the corticotroph and melanotroph cells of the hypophysis occurs without the influence of the hypothalamus which is necessary for the normal release of ACTH.  相似文献   

2.
Developmental stages of Rana esculenta, starting with the posterior limb-bud stage (stage 26) up to a few days after metamorphosis, were examined immunohistochemically to localize cells and fibers producing some POMC-derived peptides, namely, -MSH, ACTH and -END. Anti ACTH and anti -MSH revealed a positive reaction in the pars intermedia during all stages of development included in this study, whereas no immunoreactivity in this pituitary zone was ever evidenced with anti -END. In the pars distalis strongly positive cells were seen with anti ACTH and anti -END, while anti -MSH yielded weakly positive cells. Interestingly, these peptides were colocalized in the same cells. Immunoreactivity for -MSH was no longer present in the pars distalis during metamorphic climax and postmetamorphosis. In the brain of premetamorphic tadpoles, belonging to stages 26 to 30, a few neurons in the posterior telencephalon showed a positive reaction only with anti -MSH,but from stage 31 (prometamorphosis) onwards, ACTH and -endorphin-like peptide producing cells, together with -MSH-immunoreactive cells, were seen in this region and in the anterior preoptic area and infundibulum. This situation persisted in the subsequent stages of development. Anti -MSH also revealed weakly positive cells in the olfactory epithelium in premetamorphic tadpoles; strong immunoreactivity with anti -MSH was seen in olfactory epithelium cells in animals during prometamorphosis, metamorphic climax and postmetamorphosis. The possible significance of these findings is briefly discussed.  相似文献   

3.
Summary The pars intermedia of S. mossambicus contains two different endocrine-cell types. The predominant cell type is lead-haematoxyline-positive and assumed to synthesize MSH and related peptides. The second cell type is PAS positive and its function and product(s) are unknown. Staining of light-microscopic and ultrathin sections with antisera against -MSH, ACTH 1–24 and human -endorphin revealed that only the lead-haematoxyline-positive cells of the pars intermedia react with these antisera, and that the secretory granules of these cells contain compounds that were immunoreactive to all three antisera. These findings are in line with the hypothesis that -MSH, ACTH and endorphins are derived from the same precursor molecule. No specific reaction with one of the antisera could be detected in the PAS positive cells.  相似文献   

4.
Summary The ontogenesis of cells containing polypeptide hormones (ACTH, MSH, LPH, GH and Prolactin) was investigated in the fetal rat hypophysis by immunohistochemistry using the peroxidase-antiperoxidase complex.Corticotrophs, melanotrophs and lipotropic cells were revealed earlier in the pars distalis than in the pars intermedia. In the pars distalis, cells producing LPH were found in the morning of day 15 of gestation using anti-- or anti--LPH sera, and in the afternoon using anti-- or -endorphin sera. Cells containing -MSH were observed from the afternoon of day 15. The cells stainable with the anti--MSH, anti--(17-39)ACTH and anti--(l-24)ACTH sera appeared on day 16. In the pars intermedia, the cells producing -MSH, MSH, - and -endorphin, and -LPH were observed in the morning of day 17, while cells containing ACTH were only revealed in the afternoon of the same day of gestation. Based on the treatment of serial paraffin sections with various antisera, it was clearly shown that MSH, ACTH, and LPH occur in the same cells located in the pars distalis as in the pars intermedia.The development of the corticotrophs, melanotrophs and lipotropic cells does not require the presence of the fetal hypothalamus or other central nervous structures. The pituitary glands of 21 day-old fetuses encephalectomized on day 16 showed as many reactive cells as those of the littermate controls.The somatotrophs were first revealed in the pars distalis in the afternoon of day 19. The cells producing prolactin were not observed before day 21 of gestation. On some cases GH and prolactin were found together in one cell. The cytodifferentiation of GH and prolactin cells is apparently not under hypothalamic control.  相似文献   

5.
Summary A comparative study was performed on the fibre populations in tibialis anterior muscles of mouse, rat, guinea pig, rabbit, cat and dog using the two different methods of histochemical staining for myofibrillar ATPase after acid (Brooke and Kaiser 1970) or alkaline preincubations (Guth and Samaha 1970). For all species a complete correspondence existed between type I (Brooke and Kaiser 1970) and fibres (Samaha et al. 1970). Gross correspondence (>85%) existed between IIA and IIB (Brooke and Kaiser 1970) and and fibres (Samaha et al. 1970) respectively in mouse, guinea pig, rabbit, cat and dog. In the case of mouse and dog, this high degree of correspondence was based on the assumption that mouse tibialis anterior contains no type I and the dog no type IIB fibres. For the rat, a pronounced overlap existed between IIA fibres on the one hand and and fibres on the other hand as well as between IIB fibres and and fibres. These observations lead to the conclusion that the two classification schemes are not interchangeable for all species and that the two terminologies should be used only in relation with the methods from which they were derived.  相似文献   

6.
Summary Specific antisera to -melanotropin (-MSH) and corticotropin (ACTH 1-39) were used to obtain immunocytochemical evidence for the differential localization of -MSH and ACTH in the secretory granules of corticotropes of rat anterior pituitary. The specificity of the antisera was established by binding 131I-labeled -MSH and ACTH 1-39 to their respective antisera. Double-labeling immunocytochemistry (for -MSH, ferritin; for ACTH, colloidal gold) was performed. Some secretory granules were labeled with ferritin particles (-MSH), whereas others contained gold particles (ACTH). Only a few granules showed both ACTH and -MSH. In typical corticotropes (stellate in form with a small number of secretory granules aligned along the cell periphery) only some of the secretory granules that were labeled with anti-ACTH serum were also immunoreactive to anti--MSH. In atypical corticotropes (polygonal in shape and containing a large number of secretory granules) almost all of the immunoreactive ACTH secretory granules were also positive to anti--MSH serum. An intermediate type of corticotrope was observed containing a small number of secretory granules, almost all of which were labeled with anti--MSH. Thus, rat anterior pituitary corticotropes may be classified into three types according to the distribution and content of -MSH. The light-microscopic immuncytochemistry provided similar results.  相似文献   

7.
Summary Human and rabbit masticatory muscles were analyzed immuno-and enzyme-histochemically using antibodies specific to cardiac , slow and fast myosin heavy chain isoforms. In human masseter, temporalis, and lateral pterygoid muscle cardiac myosin heavy chain is found in fibres that contain either fast, or fast and slow myosin heavy chain. In rabbit masseter, temporalis and digastric muscles, fibres are present that express cardiac myosin heavy chain either exclusively, or concomitantly with slow myosin heavy chain or fast myosin heavy chain. Our results demonstrate a much broader distribution of cardiac myosin heavy chain than hitherto recognized and these might explain in part the specific characteristics of masticatory muscles. The cardiac myosin heavy chain is only found in skeletal muscles originating from the cranial part of the embryo (including the heart muscle) suggesting that its expression might be determined by the developmental history of these muscles.  相似文献   

8.
The interaction of 2-macroglobulin (2M) with an alkaline serine proteinase (ALPase I) from alkalophilicBacillus sp. grown in an extraordinarily alkaline environment was investigated. Stoichiometry of the reaction showed that ALPase I bound to 2M in a molar ratio of about 21. The 2M-ALPase I complex showed about 80% of the proteinase activity shown by ALPase I in the hydrolysis of succinyl-l-alanyl-l-alanyl-l-prolyl-l-phenylalanyl-4-methyl-coumaryl-7-amide (Suc-Ala-Ala-Pro-Phe-MCA) and casein. The conformational changes in the 2M molecule caused by the complex formation at pH 7.5 were determined from electron micrographs and difference spectra. The antigenic activity of the 2M-ALPase I complex with the anti-ALPase I antiserum was found to be completely abolished. Immunoelectrophoresis of the complex incubated at pH 7.5 after 48 h showed no appreciable change, and the complex was recognized as exhibiting enhanced stability at pH 7.5.  相似文献   

9.
Summary The adenohypophysial primordium of Xenopus laevis tadpoles at stages 33/34 to 46 (Nieuwkoop and Faber, 1956) were examined immuno-histologically for -MSH, -MSH and ACTH. -MSH was demonstrated from stage 37/38 onwards, and -MSH from stage 39. No signs of ACTH production were detected. -MSH and -MSH occurred in the same cells. No differences were found in the intensity of immunofluorescence between tadpoles which were kept on a black and a white background. The present study lends no support to the hypothesis concerning the derivation of -MSH from ACTH. The observations made suggest that the morphological formation of the pars intermedia is accomplished during stages 37/38 to 39. Acknowledgement. The authors express warm thanks to Dr. M.P. Dubois (Laboratoire de Physiologie de la Reproduction, INRA, Nouzilly, France), who prepared and verified the antibodies. Grants from Swedish Natural Science Research Council and Landshovding Per Westlings minnesfond, Lund, Sweden are gratefully acknowledged  相似文献   

10.
Summary Detailed restriction enzyme analysis of the DNA from a Chinese female showed that one of her chromosomes had a >17.5 kb deletion of DNA, including the , 2, and 1 globin genes, which is present in many Southeast Asians with an -thalassemia-1 chromosome. Her normal chromosome had the expected cluster of -like globin genes (5----2-1-3), but the segment of DNA between the two globin genes was elongated by some 0.5–0.7 kb. Analyses of various restriction sites suggested that this normal variant of the human globin gene complex is due to a crossover between a normal chromosome with () and a chromosome with an -thalassemia-2 (–3.7) and an -21-hybrid gene.  相似文献   

11.
Vasoactive peptides such as angiotensin II (AII), atrial natriuretic peptide (ANP) and vasopressin play an important role in the regulation of blood pressure. We have recently shown an augmentation of Gi levels in heart and aorta from genetic and experimentally-induced hypertensive rats, which may be attributed to the increased levels of vasoactive peptides. We have therefore investigated the effect of AII and ANP on the expression of G-proteins (Gi and Gs) in cultured vascular smooth muscle cells (VSMC) and their relationship with adenylyl cyclase activity. Exposure of VSMC with AII resulted in the augmentation of the levels of Gi-2 and Gi-3 proteins and Gi-2 and Gi-3 mRNA and not of Gs as determined by immunoblotting and Northern blotting techniques respectively. However, the stimulatory effects of N-ethylcarboxamide adenosine (NECA) and isoproterenol on adenylyl cyclase was diminished by AII treatment, whereas the inhibitory effects of AII and C-ANP4-23 were completely attenuated. On the other hand, pretreatment of the cells with C-ANP4-23 resulted in the reduction of the levels of Gi-2 and Gi-3 and not of Gs. The inhibitory responses of adenylyl cyclase to C-ANP4-23 and AII were also attenuated and the stimulatory effects of GTPgS and other agonists were significantly augmented. These data indicate that AII and ANP modulate the expression of Gia protein in a different manner. It may be suggested that the enhanced levels of Gi protein observed in hypertension may be attributed to the augmented levels of AII and not to ANP.  相似文献   

12.
The percentages of the -chain variant Hb G-Philadelphia (Hb G) or 2 68 AsnLys2 were evaluated in 84 adult and 18 newborn heterozygotes. These included members of three families who were studied in more detail by nucleic acid hybridization techniques. The adult heterozygotes fell in two categories, one with a higher proportion of Hb G [46.5±1.0% (SD), N=21] and another with lower values (33.9±3.4%, N=63). Among the newborn heterozygotes, two babies fell in the category with the higher proportion of Hb G while 16 babies gave values between 25 and 34%. Studies of -chain gene organization on the parents of one neonate with a Hb G level of 27% at birth and 37% at 8 months excluded the presence of chromosomes with triplicated -chain genes which could lead to the 0G/ genotype. Rather, these studies on five Hb G heterozygotes from three families confirmed the linkage between Hb G and a specific type of -thalassemia-2 associated with the presence of a 16-kbp Bgl II fragment which most probably carries the G locus since it has been found in 19 Hb G heterozygotes studied to date. The presence of an -thal-2 heterozygosity and three -chain genes (0G/) was confirmed among Hb G heterozygotes with lower proportions of this variant. It is likely that the even lower values found in some newborn could arise through defective assembly of G- dimers. The presence of an -thal-2 homozygosity and two active -chain genes, one on each chromosome (0G/0), was confirmed among heterozygotes with the higher proportion of Hb G. One of each of these categories was present in each of the three families investigated. This type of variability in the number of active -chain genes due to a heterozygosity or a homozygosity for -thalassemia-2 explains the trimodality of Hb S percentages among heterozygotes and the atypical hematological or biosynthetic features among patients with -thalassemia and sickle-cell syndromes.This research was supported by USPHS Research Grants HLB-05168 and HLB-15158 and by designated research funds of the Veterans Administration. This is Contribution No. 0693 of the Department of Cell and Molecular Biology, Medical College of Georgia, Augusta.  相似文献   

13.
Summary Organotypic cultures, in defined medium, of pituitary primordia obtained from 15-day-old rat fetuses were performed in order to study the in vitro differentiation of melanotrophic cells. The morphological and ultrastructural features of the transplants resembled those of the gland developing in vivo. In situ hybridization on semi-thin sections, using a 35S-labelled oligonucleotide probe, revealed pro-opiomelanocortin-mRNA-containing cells on the first day of culture in the anterior lobe and after 2–3 days in the intermediate lobe. Immunoperoxidase labelling of adjacent sections showed that the same cells reacted with antibodies against -melanocyte-stimulating hormone (MSH), 3 and adrenocorticotropic hormone in both lobes. The pro-opiomelanocortin-mRNA-containing cells formed progressively conspicuous areas in the intermediate lobe, which was almost uniformly labelled after 6 days. In the anterior lobe, these cells remained scattered in small cell groups, and colloidal gold immunolabelling showed the progressive disappearance of MSH labelling from the secretory vesicles in cells exhibiting morphological features of adult corticotrophic cells. Both the MSH content of the explants and MSH release into the culture medium increased with time. Treatment with the dopamine agonist bromocriptine induced a strong dose-dependent decrease in MSH secretion, which was significant after 3 days in culture, indicating that dopamine D2 receptors are able to regulate hormonal release of melanotrophic cells at early stages. This system constitutes a suitable model for further studies of factors controlling cell differentiation and cellular interactions involved in histogenesis.  相似文献   

14.
Résumé Les réactions d'immunofluorescence induites par l'Ac. anti -(1–24) corticotropine nous ont permis d'identifier les cellules ACTH dans le lobe antérieur de l'hypophyse d'Ellobius lutescens; il s'agit de petites cellules de forme irrégulière, à fins prolongements cytoplasmiques aboutissant à des capillaires et entourant souvent d'autres cellules préhypophysaires; ces mêmes cellules réagissent également, mais d'une façon atténuée, avec l'Ac. anti -MSH. Ce dernier induit une réaction très forte au niveau de toutes les cellules de la pars intermedia, alors que seulement certaines d'entre elles réagissent intensément avec l'Ac. anti -(1–24) corticotropine. L'improbabilité de réactions croisées entre l'Ag. -MSH et l'Ac. -(1–24) corticotropine et vice-versa est discutée. Par ailleurs, seules les cellules de la pars intermedia réagissent avec l'Ac. anti -MSH.
Immunofluorescent localisation of corticotrophic and melanotrophic hormones in the pituitary gland of the rodent Ellobius lutescens (Th)
Summary Immunofluorescence induced by the antibody to -(1–24) corticotrophin has been used to identify the ACTH cells in the anterior lobe of the pituitary gland in Ellobius lutescens. The cells are small, irregular, with fine cytoplasmic extensions ending near capillaries and often encircling other anterior lobe cell types. They also react, although less strongly, with the antibody to -MSH. The latter antibody induced a marked reaction in all cells of the pars intermedia while only some of them reacted strongly with the antibody to -(1–24) corticotrophin. The unlikeliness of cross-reactions between the antigen -MSH and antibody to -(1–24) corticotrophin is discussed. Furthermore only the cells of the pars intermedia reacted with the antibody to -MSH.

Abréviations ACTH hormone corticotrope - Ac. anticorps - Ag. antigène - Cell. cellules - C.M.C. fraction inactive de la purification d'ACTH porcine au stade 140 U/mg - C.R.F. fraction inactive de la purification d'ACTH porcine au stade 73 U/mg - Irrég. irrégulières - P.A.S. Periodic Acid-Schiff - P.A. Pars Anterior - P.I. Pars Intermedia  相似文献   

15.
Summary Heat-inactivated (60°C, 45 min)Mycoplasma capricolum strain JR cells activate murine macrophages to secrete high levels of tumór necrosis factor (TNF) and to lyse tumor target cells efficiently. Fractionation of the intactM. capricolum cells, obtained from cells harvested at the exponential phase of growth, shows that their capacity to induce TNF secretion by macrophage resides exclusively in the membrane fraction. The macrophage-mediated cytolysis following activation byM. capricolum membranes was significantly inhibited by specific anti-recombinant murine TNF antibodies.M. capricolum membranes are a potent inducer of TNF as the commonly used bacterial lipopolysaccharide, indicated by their doseresponse curve for macrophage activation. Our study further showed thatM. capricolum membranes and lipopolysaccharide synergize to augment TNF secretion by C57BL/6-derived macrophages markedly. Moreover, lipopolysaccharide-unresponsive C3H/HeJ-derived macrophages, were pronouncedly activated byM. capricolum membranes, which do not contain lipopolysaccharide. These findings suggest that the mechanism by whichM. capricolum membranes activate macrophages differs from that of lipopolysaccharide. Results of preliminary experiments show that human monocytes as well secrete TNF following activation byM. capricolum membranes. Thus, in contrast with the prohibitive toxicity of lipopolysaccharide to animals and humans,M. capricolum membranes, which contain no lipopolysaccharide and are nontoxic in nature, may be of therapeutic value in the treatment of cancer.This study was supported by the Ernst David Bergmann Fund of the Hebrew University, Jerusalem, the Concern II Foundation for Cancer Research, Los Angeles, and the Society of Research Associates of the Lautenberg Center  相似文献   

16.
Using the Boc-strategy, a step-by-step synthesis on the PAM solid supportof three aza-, iminoaza- and reduced aza-peptide homologues is described.From the same hydrazinocarbonyl peptide-PAM precursor, the coupling ofeither a Boc-amino acid or a Boc-amino aldehyde gives rise to an aza-peptideor an iminoaza-peptide containing theC-CO-NH-N-CO-NH-C orC-CH=N-N-CO-NH-C surrogate of the peptide motif, respectively. In situreduction of the latter by NaBH3CN leads to a reducedaza-peptide containing theC-CH2-NH-N-CO-NH-C moiety. The key step synthesis of thehydrazinocarbonyl peptide-PAM precursor is carried out by coupling on thegrowing peptide chain the N-Boc-aza-amino acid chloride obtained by theaction of triphosgene on the corresponding N-Boc-hydrazine. Thesemodifications have been introduced in position 1-2 of the YLGYLEQLLRbenzodiazepine-like decapeptide  相似文献   

17.
-Melanotropin and ACTH, POMC peptides, initiate biological activity by interaction with the classical pigment cell (-MSH receptor, MC1R) and adrenal gland (ACTH receptor, MC2R) melanocortin receptors, respectively. The recently discovered MC3R, MC4R and MC5R receptors provide new targets and new biological functions for POMC peptides. We have developed conformationally constrained -melanotropin peptides that interact with all of these receptors as agonists and antagonists and are examining new approaches to obtain highly selective ligands for each of these melanocortin receptors. Previously, we had converted somatostatin-derived peptides into potent and highly selective analogues that act as antagonists at the opioid receptors. Using the reverse turn template that came out of these studies, we have designed, de novo, agonist and antagonist peptide analogues that interact with melanocortin receptors.  相似文献   

18.
A-Crystallin can function like a molecular chaperone. We have recently shown that residues 71-88 in A-crystallin represent the chaperone active site of the protein. A peptide containing the sequence of A-crystallin sequence DFVIFLDVKHFSPEDLTVK (mini A-crystallin) by itself displays the antiaggregation property of A-crystallin. We have prepared a complex of reduced -lactalbumin and mini-A-crystallin and investigated the nature, conformation, and properties of the complex by dynamic light scattering, HPLC analysis, CD spectroscopy, and fluorescence studies. Although mini-A was able to prevent the precipitation of reduced -lactalbumin, large aggregates (50-500 nm) of the complex were formed during the assay. Amino acid composition estimation revealed that -lactalbumin and mini-A-crystallin were present in 1:2 ratio in the aggregates. During our study significant red shift in the Trp fluorescence emission maximum and an increase in Bis-ANS binding to the mini A-crystallin-bound -lacatalbumin were observed. The CD spectra of the complex showed a significant loss of -helical content but the -sheet content appeared to be less affected, indicating the molten-globule state of the reduced lactalbumin in the complex. These data show that the active site of A-crystallin by itself can maintain a significantly denatured and unfolded protein in soluble form.  相似文献   

19.
The adenohypophysis of the white seabream (Diplodus sargus) was studied using histochemical and immunocytochemical techniques. The adenohypophysis was composed of rostral pars distalis, proximal pars distalis and pars intermedia. Prolactin (anti-chum salmon prolactin positive) and adrenocorticotropic (anti-human ACTH positive) cells were found in the rostral pars distalis. Prolactin cells were organized into follicles, while ACTH cells were arranged in cords around neurohypophyseal tissue branches that penetrated the rostral pars distalis. In the proximal pars distalis, somatotropic (anti-chum salmon and anti-gilthead seabream growth hormone positive), gonadotropic (anti-chum salmon -gonadotrophin II and anti-carp -gonadotrophin II positive, but anti-chum salmon -gonadotrophin I negative) and thyrotropic (anti-human -thyrotropin positive) cells were observed. Growth hormone cells were restricted to the dorsal and ventral part of the proximal pars distalis. They were clustered or surrounded the neurohypophyseal branches. Only one type of gonadotrophin cell was identified and they were clustered or isolated in the proximal pars distalis. Scattered groups of thyrotropin cells were located throughout the proximal pars distalis. In the pars intermedia somatolactin (anti-chum salmon and anti-gilthead seabream somatolactin positive) and melanotropic (anti--melanotropic hormone positive) cells were localized. In addition, gonadotrophin cells surrounded the pars intermedia or distributed evenly between somatolactin and melanotropic hormone cells. Somatolactin cells were periodic acid-Schiff negative and surrounded the neurohypophyseal branches intermingled with melanotropic cells. These cells were also immunoreactive to anti-human ACTH antiserum.  相似文献   

20.
Summary A mutant strain of Rhodococcus equi accumulates three metabolites from the androst-4-ene-3,17-dione or from its degradation intermediate, 3a-H-4(3'-propionic acid)-7a-methylhexahydro-1,5-indanedione (MEPHIP). These three metabolites are: 3a-H-4a(3'-propionic acid)-5-hydroxy-7a-methylhexahydro-1-indanone--lactone (HIL); 3a-H-4(3'-trans acrylic acid)-5-hydroxy-7a-methylhexahydro-1-indanone (2'-5-hydroxy-MEPHIP); and 3a-H-4(3'-hydroxy-3'-propionic acid)-5-hydroxy-7a-methylhexahydro-1-indanone (3'-hydroxy-HIL). The behaviour of this mutant allows us to propose a pathway for degradation of the intermediates, methylperhydroindanone propionates. However, during this degradation, the side-chain propionate was eliminated by a-oxidation mechanism. Offprint requests to: A. Miclo  相似文献   

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