A Semi-Automated &lt;i&gt;in vitro&lt;/i&gt; Assay for CRF: Activities of Peptides Related to Oxytocin and Vasopressin

Af, Pearlmutter; Rapino, Eloise; Saffran, Murray

doi:10.1159/000122299

Cited by 42 publications

(11 citation statements)

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“…Vasopressin (VP), which, like CRF, has been localized in cells of the paraventricular nucleus of the hypothalamus (8), also releases ACTH, albeit with less potency than CRF, from anterior pituitary cells in vitro (1,(9)(10)(11)(12)(13) and in vivo in rats (14)(15)(16) and humans (17)(18). Although shown to be an ACTH secretagogue, the physiologic role played by VP in the regulation of ACTH secretion is uncertain (3,19,20).…”

Section: Introductionmentioning

confidence: 99%

Arginine vasopressin potentiates adrenocorticotropin release induced by ovine corticotropin-releasing factor.

Debold¹,

Sheldon²,

DeCherney³

et al. 1984

J. Clin. Invest.

183

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A bstract. Arginine vasopressin (AVP) stimulates ACTH release in man and acts synergistically with synthetic ovine corticotropin-releasing factor (oCRF) in vitro. This study was designed to examine in man the combined effects of synthetic AVP (10 U intramuscularly) and oCRF (1 gg/kg intravenously) on ACTH release.Five normal male volunteers participated in five separate experiments: (a) AVP alone; (b) oCRF alone; (c) AVP followed by oCRF 15 min later; (d) simultaneous AVP and oCRF; and (e) insulin-induced hypoglycemia. Plasma immunoreactive ACTH (IR-ACTH) and IR-cortisol were measured for 4 h after injection of each hormone; basal levels for all subjects were .9±1.2 pg/ml and 4. 9±0.4 ,gg/dl (mean±SE), respectively. AVP and oCRF, when given individually, caused rapid rises in IR-ACTH to similar peak levels of 25±6.6 and 33±4.6 pg/ml, respectively. AVP given 15 min before oCRF caused a 2.6-fold potentiation ofthe oCRF response, with a peak IR-ACTH of 85±4.6 pg/ml. AVP given at the same time as oCRF produced a fourfold potentiation of the peak IR-ACTH response to 132±11 pg/ml. These ACTH responses were far greater than those previously observed after 30-fold greater doses of oCRF alone. By way of comparison, insulin-induced hypoglycemia caused a peak IR-ACTH of 169±20 pg/ml. IR-ACTH returned to base line at 60-90 min after AVP alone, whereas the prolonged effect of oCRF was apparent whether it was given alone or in combination with AVP. The mean peak IR-cortisol responses to AVP, oCRF, and AVP given 15 min before oCRF were similar (16.5±0.9, 16.4±2.3, and 18.5±0.8 ,ug/dl, respectively), but the peak IR-cortisol responses to AVP and oCRF given simultaneously and to insulininduced hypoglycemia were 1.5 and 1.7 times greater, respectively. IR-cortisol returned to base line within 2-3 h after AVP alone, but remained elevated for at least 4 h after oCRF alone or in combination with AVP. These results indicate that AVP acts synergistically with oCRF to release ACTH in man and suggest that AVP may play a physiologic role in modulating the ACTH response mediated by corticotropin-releasing factor.

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Section: Introductionmentioning

confidence: 99%

Arginine vasopressin potentiates adrenocorticotropin release induced by ovine corticotropin-releasing factor.

Debold¹,

Sheldon²,

DeCherney³

et al. 1984

J. Clin. Invest.

183

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“…The relationship between CRF and pressor or antidiuretic attivity of various vasopressin analogues is in dispute (16)(17)(18)(19)(20). Recently Aizawa et al found that CRF and pressor activities of several vasopressin analogues were strongly correlated, whereas CRF and antidiuretic activities were hot (21).…”

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confidence: 99%

Properties of rat anterior pituitary vasopressin receptors: relation to adenylate cyclase and the effect of corticotropin-releasing factor.

Gaillard¹,

Schoenenberg²,

Favrod-Coune³

et al. 1984

Proc. Natl. Acad. Sci. U.S.A.

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Crude plasma membrane fractions were prepared from female Wistar rat anterior pituitaries. These fractions contained a single population of specific 3H-labeled [8- Corticotropin-releasing factor activated, and angiotensin inhibited, the adenylate cyclase activity of pituitary membranes. Under the same experimental conditions, vasopressin did not influence adenylate cyclase activity nor did it affect the corticotropin-releasing factor-induced activation. These data support the view that vasopressin is one component of the multifactorial regulation of corticotropin release and that it acts through a cAMP-independent pathway. The potentiation by vasopressin of corticotropin-releasing factor-induced cAMP accumulation in intact cells very likely proceeds through indirect mechanisms, which are not expressed in broken cell preparations.Despite abundant evidence (1-6) that the 41-residue peptide recently isolated from ovine hypothalami (7) is a physiological corticotropin-releasing factor (CRF), the hypothalamic factor responsible for the integrated release of corticotropin (ACTH) seems not to be a single peptide but a multifactorial complex (8, 9). Vasopressin has been proposed as a constituent of this complex (9, 10). There are several pieces of evidence in favor of this concept: the synergism observed between ovine CRF and vasopressin (10, 11); the coexistence of immunoreactive neurophysin/vasopressin and CRF in nerve terminals of the zona externa of the median eminence (12) and in cells of the paraventricular nucleus (13); and finally high levels of vasopressin in portal blood (14). Further support for the role of vasopressin in the CRF complex includes the potentiation of the Brattleboro rat CRF activity by addition of synthetic vasopressin (15) and recent chromatographic investigations (9,15 2907The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

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“…Because vasopressin has CRF activity [10] and has been reported to be present in the ME [3], one explanation of the experiment described above is that the CRF activity of the column-bound material could be due to the endogenous va sopressin content of the rat ME. Therefore, in order to esti mate the vasopressin content, we determined the pressor ac tivity of rat ME extracts (fig 1).…”

Section: Resultsmentioning

confidence: 99%

“…CRF activity was determined with a semiautomated in vitro bioassay which utilizes rat pituitary halves in a static incubation and adrenal quarters in a continuous superfusion system [10]. In this bioassay, matched sets of rat pituitary halves are incubated first with a standard extract of 1 ME.…”

Section: Methodsmentioning

confidence: 99%

“…In our laboratory we have shown that the most potent CRF among peptide hormones of known structure is arginine va sopressin (AVP). However, detailed analyses of the CRF ac tivity of AVP have shown that approximately 40 pg of AVP would be required to produce the CRF activity equivalent to that of one rat median eminence (ME), which is far great er than the known AVP content of the rat M E [ 10], We have found that a crude acid extract of the ME of the Brattleboro rat, which is genetically deficient in AVP, contains as much CRF activity as the ME of normal rats in a whole tissue bioassay for CRF [8], In addition, the CRF activity in a ME extract of normal rats is due to at least two factors, which must be combined to obtain full activity [11].…”

mentioning

confidence: 99%

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Properties of CRF from Normal and Brattleboro Rat Median Eminence

Af¹,

La²,

Loeser³

et al. 1982

Neuroendocrinology

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Most of the corticotrophin-releasing factor (CRF) activity of normal rat median eminence (ME) extract binds to a neurophysin affinity column. The bound material contains the large and small factors, which we have previously demonstrated to be required together for full activity. Most of the CRF activity of Brattleboro rat ME extract, which contains as much CRF activity as the ME extract of a normal rat, does not bind to a neurophysin affinity column. The CRF activity of Brattleboro rat ME extract resides entirely in a large molecule as determined by Sephadex G-25 chromatography. The different properties of Brattleboro and normal rat CRF suggest that the CRF activity in the Brattleboro rat may result from a substance which is different from that in a normal rat.

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A Semi-Automated <i>in vitro</i> Assay for CRF: Activities of Peptides Related to Oxytocin and Vasopressin

Cited by 42 publications

References 1 publication

Arginine vasopressin potentiates adrenocorticotropin release induced by ovine corticotropin-releasing factor.

Arginine vasopressin potentiates adrenocorticotropin release induced by ovine corticotropin-releasing factor.

Properties of rat anterior pituitary vasopressin receptors: relation to adenylate cyclase and the effect of corticotropin-releasing factor.

Properties of CRF from Normal and Brattleboro Rat Median Eminence

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