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W E Stumpf

Publications and source records attributed to W E Stumpf.

At least 181 records · Page 10Linked to original sources
PubMed1981

Effect of 1,25 dihydroxyvitamin D3 on insulin secretion.

Recent autoradiographic studies demonstrated that B-cells concentrate 1,25 (OH)2 D3 in their nuclei, suggesting a genomic action on B-cell function. This study was undertaken to investigate the effects of 1,25 (OH)2 D3 on insulin secretion in vitamin D-deficient rats. Mature vitamin D-deficient rats were injected with 1,25 (OH)2 D3 or the ethanol-isotonic saline vehicle. Administration of 1,25 (OH)2 D3 to 10 rats resulted in a 17 microunits/ml (113%) increase in insulin levels and 0.9 mg/dl (16%) increase in plasma calcium. No changes were found in insulin or calcium levels in 5 control rats given vehicle alone. A group of vitamin D-deficient rats with plasma calcium levels of 5.4 +/- 0.1 mg/dl had insulin levels that were the same as those observed in a group of vitamin D-deficient rats with plasma calcium levels of 6.3 +/- 0.1 mg/dl. The difference in calcium levels between these two groups is similar to the increase in plasma calcium found after 1,25 (OH)2 D3 administration. The results of these studies indicate that 1,25 (OH)2 D3 action on pancreatic B-cells affects insulin secretion. Since insulin increases synthesis of 1,25 (OH)2 D3, the existence of a feedback loop between B-cells and kidney proximal tubule cells is suggested.

Animals↗
PubMed1981

Combined autoradiography and immunohistochemistry for simultaneous localization of radioactively labeled steroid hormones and antibodies in the brain.

A combined technique of autoradiography and immunohistochemistry is described for localization of radioactively labeled ligands and antibodies to neuropeptides, protein hormones and neurotransmitter synthesizing enzymes in the brain. This method permits the simultaneous visualization of radioactively labeled cells and neuropeptide-producing cells in the same tissue preparation. Autoradiograms are fixed with weak paraformaldehyde solution prior to photographic processing for subsequent immunoperoxidase staining. With this procedure 3H-estradiol is localized in neurophysin I and arginine vasopressin-producing cells of the mouse supraoptic and paraventricular nuclei, neurophysin-producing cells of the guinea pig hypothalamus, and dopamine-beta-hydroxylase-containing neurons of the rat lower brainstem; 3H-dihydrotestosterone in pituitary gonadotropes and thyrotropes; and 3H-1,25-(OH)2 vitamin D3 in pituitary thyrotropes and pancreatic B-cells.

Animals↗
PubMed1981

Combined autoradiography and formaldehyde-induced fluorescence methods for localization of radioactively labeled substances in relation to monoamine neurons.

A combined technique of formaldehyde-induced fluorescence (FIF) and autoradiography is described for the localization of radioactively labeled substances in relation to monoamine neurons. This method permits the simultaneous visualization of 3H-labeled steroid hormone or drug uptake sites and fluorescing monoamine neural elements (cell bodies, fiber projections, terminals) in the same tissue section. Thin frozen sections cut in a cryostat are freeze-dried, exposed to formaldehyde vapor at 80 degrees C, and carried through dry-mount autoradiography processing steps before fluorescence microscopy screening. Subsequent histological staining of sections and light microscopy are employed for conventional autoradiogram screening. With this procedure, 3H-estradiol and 3H-dihydrotestosterone are localized in various catecholamine (CA) neurons in the diencephalon and lower brain stem of the rat. Also, catecholaminergic as well as noncatecholaminergic sex steroid target neurons are seen to be innervated by CA terminals in various rat brain regions.

Animals↗
PubMed1981

Quantitative assessment of steroid hormone binding sites by thaw-mount autoradiography.

A procedure for the quantitative assessment of nuclear receptors for steroid hormones--and other substances--in individual cells is presented. Thaw-mount autoradiography, a procedure developed earlier in our laboratory, is utilized. The silver grain yield (specific activity) is 16.6 disintegrations per silver as determined fo tritium in guinea pig uterine tissues. An integrated formula is presented and applied for 3H-estradiol, 3H-diethylstilbestrol, and 3H-aldosterone in sampled tissue. A comparison with data derived from the literature that are based on the homogenization of whole uteri and biochemical analysis shows comparable values wtih the autoradiographic data if the latter are pooled. The pooled ata indicated 12-14,00 molecules of 3H-estradiol per uterine nucleus, while subpopulations of target cells vary between 5,000 and 28,000 per nucleus.

Animals↗
PubMed1981

Sexual differentiation of the urogenital tract in the chicken embryo: autoradiographic localization of sex-steroid target cells during development.

The determinant role ascribed to steroid hormones in sexual differentiation of the reproductive tract of the embryo implies the presence of target cells for sex steroids. An autoradiographic technique adapted for diffusible compounds was employed to characterize and localize cells which concentrate either [3H]oestradiol (E2) or [3H]dihydrotestosterone (DHT) in their nuclei. This paper describes the topographical distribution of cells containing receptor sites for oestrogen or androgen in various tissues of the reproductive tract of chicken embryos from day 6 to 15 of incubation. Receptor sites for oestradiol are present in the mesenchyme of the cloaca and in urodeum and vascular body. In the lower part of the Wolffian duct, only epithelial cells display nuclear labelling. In the Müllerian duct, nuclear receptor sites for [3H]oestradiol are observed not before day 15. Receptor sites for DHT are localized in the mesenchyme of the cloacal region from day 7 to 15. The Wolffian, but not the Müllerian duct contains receptor sites for DHT in the nuclei of epithelial and mesenchymal cells. Cross-competition experiments between [3H]E2 or [3H]DHT and unlabelled DHT or E2 respectively, show that 2 different types of receptor sites exist. The observations indicate: (a) complementary roles forffian, but not the Müllerian duct contains receptor sites for DHT in the nuclei of epithelial and mesenchymal cells. Cross-competition experiments between [3H]E2 or [3H]DHT and unlabelled DHT or E2 respectively, show that 2 different types of receptor sites exist. The observations indicate: (a) complementary roles forffian, but not the Müllerian duct contains receptor sites for DHT in the nuclei of epithelial and mesenchymal cells. Cross-competition experiments between [3H]E2 or [3H]DHT and unlabelled DHT or E2 respectively, show that 2 different types of receptor sites exist. The observations indicate: (a) complementary roles for oestrogenic and androgenic hormones in embryonic sexual differentiation; (b) precocity of receptors for sex hormones during embryonic development; (c) importance of mesenchyme in differentiation processes which are sex-steroid dependent.

Animals↗
PubMed1981

The bursa of Fabricius of the chicken embryo: localization and ontogenic evolution of sex-steroid target cells.

Androgenic hormones induce inhibition or regression of the bursa of Fabricius in the chick embryo. The high doses of hormones necessary to this involution raises the question of the processes involved and their putative role in the normal development of the bursa. If androgens play a role it is mediated by receptor sites in target cells. Using an autoradiographic technique, receptor sites for androgenic hormones were localized in mesenchymal cells of the bursa from the primordium (7-day embryo) up to the fully differentiated immune organ (15-day embryo). No target cells containing receptor sites in their nuclei were observed in the endodermic epithelium or the follicles. Oestrogen target cells in very small number are found in the mesenchyme of the bursa, in 15-day embryos. The early presence of receptor sites for steroid hormones in the bursa of Fabricius shows that the normal development may be influenced by androgens, but the actual effects are yet to be demonstrated.

Animals↗
PubMed1980

1,25-Dihydroxyvitamin D3 stimulated increase of 7,8-didehydrocholesterol levels in rat skin.

A convenient, accurate assay was developed for determining skin cholesta-5,7-dien-3 beta-ol (7,8-didehydrocholesterol) concentrations. Ultraviolet spectrophotometry provided quantitation of the sterol from rat skins following saponification and chromatography on Lipidex and high-performance liquid chromatography. Correction for recoveries was accomplished by using 7,8-didehydro[3 alpha-3H]cholesterol as an internal standard. Chronic dosing of vitamin D-deficient rats with 1,25-dihydroxyvitamin D3 caused a 4-fold increase in skin 7-dehydrocholesterol content. This rise was not the result of changes in food consumption, body weight, or plasma calcium. Cholesterol concentrations were not significantly elevated although some of the other nonsaponifiable lipid components found in the high-performance liquid chromatogram appeared to be increased by the treatment. These results suggest that the vitamin D hormone 1,25-(OH)2D3 may exert a positive feedback regulation on the production of vitamin D3 in skin.

Animals↗
PubMed1980

Estrogen target cells in the forebrain of river lamprey, Ichthyomyzon unicuspis.

Estrogen-concentrating cells in the brain of river lamprey, Ichthyomyzon unicuspis, are identified and mapped by thaw-mount autoradiography. After injection of 3H-estradiol-17 beta, cells with nuclear concentration of radioactivity are found in the ventral periventricular area of the telencephalon, and in preoptic, central hypothalamic, and thalamic regions of the diencephalon, while in the pallium no such target cells are found. Injection of unlabeled estradiol prior to the administration of 3H-estradiol reduces of eliminates the nuclear concentration of radioactivity. The autoradiographic results demonstrate the presence of estrogen target cells in the brain of descendents of one of the phylogenetically earliest vertebrate lines. The topographical distribution of these target neurons, which are accumulated in certain periventricular structures, is similar to the distribution of estrogen target neurons described previously for other nonmammalian and mammalian vertebrates. Accordingly, estrogen feedback and activation sites are present throughout vertebrate phylogeny.

Animals↗
PubMed1980

Brainstem catecholamine neurons are target sites for sex steroid hormones.

Sex steroid hormones and catecholamines have physiological interactions in the brain. By the combined use of autoradiography and fluorescence histochemistry, steroid hormone target sites and catecholamine neurons were visualized simultaneously in the same tissue preparation. By this dual localization method, [3H]estradiol and [3H]dihydrotestosterone target sites were identified in nuclei of many catecholamine cell bodies in the brainstem, and catecholamine nerve terminals were observed near certain steroid hormone target neurons. These results suggest close anatomical interrelations between steroid hormone sites of action and catecholamine sites of production and action in the brain.

Adrenalectomy↗
PubMed1980

"Peer" review.

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Government Agencies↗
PubMed1980

Thyrotropes in the pituitary are target cells for 1,25 dihydroxy vitamin D3.

In the anterior pituitary of the rat, target cells of 1,25 (OH)2 vitamin D3 are identified as those that secrete thyroid stimulating hormone by means of a combined technique of thaw-mount autoradiography and immunohistochemistry. The results for the first time provide evidence that suggests a central effect of 1,25 (OH)2 vitamin D3 on the modulation of thyrotropin secretion in a manner similar to that of other steroid hormones at the level of the pituitary.

Animals↗
PubMed1980

Target cells for 1,25 dihydroxyvitamin D3 in the pancreas.

Mature rats raised on a vitamin D deficient diet were injected with tritium labeled, 1,25 dihydroxyvitamin D3. Concentration of radioactivity, which is prevented by pretreatment with unlabeled 1,25 dihydroxyvitamin D3, is found in nuclei of cells that are centrally located in pancreatic islets. The central location of these cells and supportive evidence from the literature suggest that they are B-cells, and that 1,25 dihydroxyvitamin D3 has a direct and genomic action on B-cell functions including insulin secretion.

Animals↗
PubMed1980

LHRH-systems in the brain of the golden hamster.

Vibratome sections of male hamster brains were treated immunohistochemically with LHRH antiserum, and the anatomical distribution of LHRH immunoreactive cells and nerve fibers was assessed. LHRH-cell bodies are found in the ventral hypothalamus that includes its preoptic, anterior and central parts, in the septum, the olfactory tubercle, the main and accessory olfactory bulb, and the prepiriform cortex. In addition, extracerebral LHRH-neurons and ganglia exist in LHRH-positive nerves at the ventromedial surface of the olfactory tubercle and bulb as well as in olfactory nerves. Dense networks of LHRH-immunoreactive fibers are found in all regions where LHRH-cell bodies exist. Intraseptal connections reach the organum vasculosum of the lamina terminalis, the subfornical organ, and the lateral ventricle. Dorsolateral projections from the septum can be traced via the fimbria hippocampi and alveus to the ventral hippocampus, via the stria terminalis to the amygdala and piriform cortex. Ventrolateral projections extend from the level of the olfactory tubercle and preoptic-anterior hypothalamic area via the ventral amygdalofugal pathway to the prepiriform and piriform cortex as well as the amygdala. Dorsal supracallosal projections via the stria longitudinalis are seen in the induseum griseum and the cingulate cortex. Caudal efferents reach the havenula, interpeduncular nucleus, midbrain raphe, and central gray of the rostral fourth ventricle via the stria medullaris and fasciculus retroflexus and by a ventral projection via the periventricular and subventricular hypothalamus. A major portion of this ventrocaudal projection gives rise to a dense network in the median eminence. Anatomical relationships of LHRH-fibers to certain regions of the inner ventricular and outer brain surface are noted.

Animals↗
PubMed1980

Estrogen receptors in mammary gland primordia of fetal mouse.

Swiss albino mice were injected on day 16 of pregnancy with 3H diethylstilbestrol. Fetuses were sacrificed 3 h afterwards, frozen, and processed for thaw-mount autoradiography. The serial sections from 4 fetuses were studied. Intense nuclear concentration of radioactivity was found in the mesenchymal cells directly surrounding the epithelial primordia of the mammary glands, but not in the epithelium itself. Localization was similar in male and female fetuses. These findings are discussed in relation to their developmental, teratological, and onocological implications.

Animals↗
PubMed1980

Immunohistochemical identification of cells in the pars distalis of the pituitary of the lizard Anolis carolinensis.

Immunocharacteristics of the pars distalis cells of the pituitary of the male lizard A. carolinensis are determined by employing the immunoperoxidase technique with antisera to mammalian pituitary hormones. On the basis of their immunoreactivity, 5 different cell types with characteristic anatomical distribution are recognized. ACTH cells are found in the rostral half of the pars distalis, and PRL cells in the rostral two thirds of the pars distalis. GH and TSH cells are located in the caudal half of the pars distalis. GTH cells are distributed throughout the gland. When consecutive sections are stained with antiserum to ovine FSH or its beta-subunit and to ovine LH, the same cells show immunoreactivity to all the three antisera. None of the GTH cells show positive immunoreactivity to ovine beta-LH antiserum. The results suggest the existence of one gonadotropic cell type in the pituitary of this lizard.

Adrenocorticotropic Hormone↗
PubMed1980

Simultaneous localization of [3H]estradiol and neurophysin I or arginine vasopressin in hypothalamic neurons demonstrated by a combined technique of dry-mount autoradiography and immunohistochemistry.

A combined technique of dry-mount autoradiography and immunoperoxidase staining is described for the localization of steroid hormones and neuropeptides in the same brain section. With this procedure [3H]estradiol is localized in nuclei of neurophysin and arginine vasopressin producing cells of the mouse supraoptic and paraventricular nucleus. The results suggest a direct action of estradiol on neurohypophysial hormone producing cells. This immunoautoradiographic technique is suitable for the simultaneous localization of steroid hormones and neuropeptides in the brain.

Animals↗