PubMed Health⌕ Search

Biomedical subjects

S Vigh

Publications and source records attributed to S Vigh.

At least 55 records · Page 3Linked to original sources
PubMed1983

Radioimmunoassay of CRF-like material in rat plasma: validation of the method.

The availability of antibodies against the ovine corticotropin releasing factor (CRF), which cross-react with a CRF-like immunoreactivity (CRF-LI) in the rat, has enabled us to develop a radioimmunoassay (RIA) for rat CRF-LI in plasma and crude hypothalamic extracts. 125I-Tyr CRF 1-41 was used as the tracer, and synthetic ovine CRF as the reference hormone. The precision profile of the assay indicates a high degree of reproducibility except for the lower dose range. The minimum detectable dose was 20 pg/tube. This assay can detect differences in plasma CRF-LI levels after various manipulations that simultaneously alter the ACTH levels in plasma. A wide range of CRF concentrations has been found in plasma of normal rats. Caution should be exercised in the interpretation of the values obtained since an ovine RIA system was used.

Adrenocorticotropic Hormone↗
PubMed1982

Synthesis and biological properties of ovine corticotropin-releasing factor (CRF).

The 41-residue sequence of recently identified ovine corticotropin-releasing factor (CRF) was assembled on a benzhydrylamine resin support. Deprotection and cleavage from the resin were accomplished by HF treatment. The crude peptide was purified by gel filtration and reverse-phase, medium pressure, followed by high-performance liquid chromatography (HPLC). In addition to the usual criteria, the homogeneity of the final material, obtained in 7% yield, was assessed by the isolation and examination of cyanogen bromide cleavage and tryptic digestion fragments by HPLC and amino acid analysis. The synthetic 41 amino acid CRF stimulated the release of corticotropin (ACTH) in three in vitro systems: isolated rat pituitary quarters, monolayer cultures of dispersed pituitary cells, and superfused pituitary cells on a column, the responses being related to the log-dose of CRF in the range of 0.05-125 ng/ml. The synthetic peptide also augmented in vivo release of ACTH in rats pretreated with chlorpromazine, morphine, and Nembutal, as assessed by the measurement of serum corticosterone. The data indicates chemical purity and high biological activity of synthetic material.

Adrenocorticotropic Hormone↗
PubMed1982

Immunocytochemical localization of corticotropin-releasing factor (CRF) in the rat brain.

The immunocytochemical localization of neurons containing the 41 amino acid peptide corticotropin-releasing factor (CRF) in the rat brain is described. The detection of CRF-like immunoreactivity in neurons was facilitated by colchicine pretreatment of the rats and by silver intensification of the diaminobenzidine end-product. The presence of immunoreactive CRF in perikarya, neuronal processes, and terminals in all major subdivisions of the rat brain is demonstrated. Aggregates of CRF-immunoreactive perikarya are found in the paraventricular, supraoptic, medial and periventricular preoptic, and premammillary nuclei of the hypothalamus, the bed nuclei of the stria terminalis and of the anterior commissure, the medial septal nucleus, the nucleus accumbens, the central amygdaloid nucleus, the olfactory bulb, the locus ceruleus, the parabrachial nucleus, the superior and inferior colliculus, and the medial vestibular nucleus. A few scattered perikarya with CRF-like immunoreactivity are present along the paraventriculo-infundibular pathway, in the anterior hypothalamus, the cerebral cortex, the hippocampus, and the periaqueductal gray of the mesencephalon and pons. Processes with CRF-like immunoreactivity are present in all of the above areas as well as in the cerebellum. The densest accumulation of CRF-immunoreactive terminals is seen in the external zone of the median eminence, with some immunoreactive CRF also present in the internal zone. The widespread but selective distribution of neurons containing CRF-like immunoreactivity supports the neuroendocrine role of this peptide and suggests that CRF, similarly to other neuropeptides, may also function as a neuromodulator throughout the brain.

Animals↗
PubMed1982

The effect of perinatal oestrogen treatment on the troph-hormone secreting cells of the anterior pituitary of the rat.

Late effect of the perinatal administration of oestradiol dipropionate on pituitary gonadotrophs and the morphology of the LH-RH neuronal system was tested both in male and female rats. Oestrogen caused a severe reduction in the number and size of immunodetectable gonadotrophs in both sexes. By the 90th day of life, however, immunomorphology and distribution of the gonadotroph cells had became normal, and also the LH-RH system of the animals was similar to that of the intact controls. The lack of vaginal cycles indicated, however, that oestrogen might have permanently impaired higher brain centers regulating cyclic gonadotroph hormone release.

Animals↗
PubMed1981

High molecular weight peptide with corticotropin-releasing factor activity from porcine hypothalami.

The presence of a corticotropin-releasing factor (CRF) behaving as a peptide with a molecular weight of about 5000 was established after purification of porcine hypothalamic extracts by gel filtration on Sephadex G-25 and then on Sephadex G-50. Purified CRF stimulated the release of corticotropin (ACTH) in three in vitro systems: isolated rat pituitary quarters, monolayer cultures of dispersed pituitary cells, and superfused pituitary cells on a column. A linear logarithmic dose-response relationship existed between 50 and 200 micrograms of CRF preparations per ml and the total amount of ACTH released by the superfused pituitary cells. The pituitary ACTH response to CRF in the pituitary quarters system was also approximately linearly related to the logarithm of the dose of CRF. CRF also stimulated in vivo release of ACTH in rats pretreated with chlorpromazine, morphine, and Nembutal. CRF activity was labile to digestion with trypsin and chymotrypsin and was partially destroyed by pepsin. The evidence indicates that CRF of porcine origin is a polypeptide of a higher molecular weight than previously assumed.

Animals↗
PubMed1976

Cell differentiation of the fetal rat anterior pituitary in vitro.

Adenohypophysial primordia of rat embryos at 13 to 15 days gestation were cultured in Parker 199 synthetic medium for 2 to 11 days. At the end of the culture period their fine structure and the presence of immunoreactive trophic hormones using the peroxidase-labeled antibody technique were investigated. The degree of differentiation in the glands depends largely on the age of the embryos furnishing the explants. Cultured pituitaries explanted on the 13th day of gestation contain only ACTH-positive cells and about 15% of the cells are granular. The granules are 50-100 nm in diameter in some cells, while in other cells they range from 50 to 200 nm. In cultivated adenohypophysial primordia of embryos on the 15th day of intrauterine life ACTH, prolactin, LH and TSH cells are evident, but only the same two kinds of granular cells can be observed with the electron microscope. The extent of cytodifferentiation in the glands explanted on the 14th day of gestation is intermediate between the two other groups. The data suggest that the fetal rat pituitary has the capacity of self-differentiation but to a lesser extent than that of the in situ hypophysis.

Adrenocorticotropic Hormone↗
PubMed1976

Functional differentiation of the FSH-synthesizing cells in the pars distalis of the fetal pituitary gland of the rat.

The onset of FSH synthesis in the embryonic pituitary gland of the rat was studied by a peroxidase-labelled antibody method. The first FSH-containing cells appeared on the 20th day of embryonic life. From that day onwards, FSH cells increased rapidly in number. It was found that in adult animals some pituitary cells reacted with both anti-HCG and anti-FSH sera, indicating the simultaneous presence of LH and FSH in the same cell.

Animals↗
PubMed1975

LH-RH-containing neural elements in the rat hypothalamus.

With the use of rabbit anti-LH-RH serum, a system of delicate nerve fibers and terminals which contain immunoreactive LH-RH can be demonstrated in the median eminence of the rat, corresponding exactly to the tubero-infundibular tract as described earlier with the aid of classical neurophistological methods. The delicate fiber system can be traced to the region of the rectrochiasmatic area and especially to that of the arcuate nucleus but not farther. Nerve cells do not show any immunopositive reaction for LH-RH in the experimental conditions studied. LH-RH positive nerve fibers terminate on or in the immediate vicinity of the capillary loops penetrating the median eminence.

Animals↗