Influence of the Pituitary Gland on Sodium Conservation, Plasma Renin and Renin Substrate Concentrations in the Rat

Goodwin, F. J.; Kirshman, J. Dianne; Sealey, Jean E.; Laragh, John H.

doi:10.1210/endo-86-4-824

Cited by 27 publications

(12 citation statements)

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“…2A indicates there is a log dose relationship between 0*05 and 5-0 nm, there being no significant difference between the effects of 2-5, 5, 25 and 50 nm. Occasionally action potentials were recorded in the presence of All at concentrations of 0-03 nm, which is the normal value for All in rat plasma (Goodwin, Kirshman, Sealey & Laragh, 1970). The discharge pattern found with this dose of All was similar to that found in the presence of 0-05 nM-AII.…”

Section: Resultssupporting

confidence: 71%

The neuronal organization of the rat subfornical organ in vitro and a test of the osmo‐ and morphine‐receptor hypotheses.

Buranarugsa¹,

Hubbard²

1979

The Journal of Physiology

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SUMMARY1. Extracellular action potentials (units) were recorded from rat subfornical organ explants in vitro in response to addition of angiotensin II (All) or carbamylcholine (carbachol) or serotonin (5-HT) to the superfusion solution. The frequency recorded was dose dependent over a wide range (All, 0 05-5 nM; carbachol, 2-7-2700 nM; 5-HT, 1-100 nM). Appropriate antagonists, sarcl-ala2 angiotensin (saralasin) for All, atropine sulphate for carbachol and methysergide maleate for 5-HT, blocked these excitations. The effects were reversible except for that of atropine.2. Two populations of AII-excited units were found. A superficial population lying between 15 and 45 4um from the ependymal surface was blocked only by saralasin and another population lying more than 55 ,#m below the ependymal surface could be blocked by atropine as well as saralasin. Carbachol-evoked units generally lay below 45 #um, and 5-HT-evoked units were scattered evenly over the subfornical organ. It is suggested that superficial AII-excited neurones have a cholinergic excitatory synapse with the deeper carbachol-excited neurones.3. No evidence was found for the hypothesis that neurones of the subfornical organ are excited by morphine or by changes in extracellular osmotic pressure.4. All types of drug-excited unit, both superficial (15-55 gim) and deep (below 55 gin), could be driven polysynaptically from the body or columns of the fornix. Units driven antidromically or antidromically and synaptically were almost all more than 55 stm from the surface. 5-HT-evoked units were driven antidromically only by stimulation of the columns of the fornix. All-and carbachol-evoked units could be driven antidromically or antidromically and synaptically by stimulation of the body or the columns of the fornix. It is suggested that All units driven antidromically are actually carbachol-sensitive neurones driven by the more superficial AII-sensitive cells. 5. A model of the neuronal organization of the subfornical organ is suggested in which AII-sensitive neurones lying superficially are excited by substances borne by blood or cerebrospinal fluid and synapse with deeper carbachol-sensitive neurones. The axons of these deep neurones pass out of the subfornical organ in the columns and body of the fornix. Afferent fibres from the body and columns of the fornix polysynaptically excite both superficial and deep neurones. A recurrent inhibitory circuit is suggested on the output path.

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Section: Resultssupporting

confidence: 71%

The neuronal organization of the rat subfornical organ in vitro and a test of the osmo‐ and morphine‐receptor hypotheses.

Buranarugsa¹,

Hubbard²

1979

The Journal of Physiology

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“…This difference may be attributed to our better recoveries of angiotensin, to the presence of NaCl (15) and/or absence of Dowex resin in the incubation mixtures. This microprocedure differs from others, in that homologous substrate is used instead of hog renin substrate (2), and it does not involve adsorption on and elution of the angiotensin from the Dowex resin ( l ) , thus, saving time and eliminating losses of angiotensin. Its only limitation is the number of samples that can be bioassayed.…”

Section: Procedures For Plasma Renig Determinationmentioning

confidence: 99%

“…However, recovery is not complete, and elution of the resin and concentration of the eluate is timeconsuming. Recently, Goodwin et al (2) have applied to the rat the method that Gould et al ( 3 ) had used for human plasma. Plasma samples are incubated with hog renin substrate during 16 hr in the presence of angiotensinase inhibitors.…”

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confidence: 99%

A Method for the Measurement of Plasma Renin in the Rat

Nasjletti

Masson

1971

Experimental Biology and Medicine

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Most of the methods for the measurement of plasma renin cannot be used in the rat because of the large volume of plasma required, hence the need for a micromethod. The one most widely used has been devised by Boucher et al. (1). Plasma samples are incubated during 12 hr with an excess of homologous substrate in the presence of Dowex resin which adsorbs and protects angiotensin from angiotensinases. This method is sensitive and specific. However, recovery is not complete, and elution of the resin and concentration of the eluate is timeconsuming. Recently, Goodwin et al. (2) have applied to the rat the method that Gould et al. ( 3 ) had used for human plasma. Plasma samples are incubated with hog renin substrate during 16 hr in the presence of angiotensinase inhibitors. Recovery of angiotensin was complete after 16 but not after 24-hr incubation.The method presently described is also similar to that of Gould et al. but, like the Boucher et at?. ( 1 ) procedure, uses homologous substrate. I t is simple, accurate, and permits routine determinations of plasma renin in large numbers of samples.Materials and Methods. Preparation of renin substrate. Blood from 48-hr bilaterally nephrectomized male rats was collected in the presence of disodium ethylenediaminetetraacetate (EDTA) . Renin substrate was then extracted and purified by ammonium sulfate fractionation and acid treatment (4).Following addition of 10 ml of 0.3 M EDTA to 100 ml of plasma, the mixture was stirred slowly for 30 min and then adjusted to pH 6 with 5 N HCI. Ammonium sulfate was slowly added to a concentration of 0.97

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“…The pituitary factor responsible for these effects is not known. Studies on interactions of pituitary hormones on the renin-angiotensin system and on electrolyte balance have so far failed to elucidate primary mechanisms (Goodwin, Kirshman, Sealey & Laragh, 1970;Goodwin, Ledingham & Laragh, 1970).…”

Section: Discussionmentioning

confidence: 99%

Vasopressin Effects on Plasma Renin Activity in Male and Female Rats

1978

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1. The influence of gonadal and pituitary factors on the plasma renin response to exogenous vasopressin was examined in anaesthetized rats.2. Plasma renin activity (PRA) was measured in Brattleboro rats (with and without hypothalamic diabetes insipidus) and Long-Evans male and female rats, before and after single intravenous injection of antidiuretic hormone (ADH) or saline.3. Control saline injections did not change PRA. ADH reduced PRA in male, but increased PRA in female rats. Rats with diabetes insipidus displayed the greatest changes and were used in subsequent experiments. Extrarenal renin activity (nephrectomized rats) gave qualitatively similar responses to ADH. Plasma renin concentration, which was also measured with PRA in intact and nephrectomized male and female rats with diabetes insipidus, increased in the females and decreased in the males after ADH.4. Castration, 24 h before study, abolished the ADH-induced fall in PRA, and testosterone implanted before castration did not restore the response. Cyproterone acetate reversed the ADH effect in males, so that PRA then rose after ADH. Hypophysectomized male rats, with depressed basal plasma renin activities, also showed a reduced PRA after ADH. 5. Ovariectomy had little effect on the ADHinduced renin release and the response was similar at oestrus, metoestrus and dioestrus. In hypophysectomized female rats ADH reduced PRA; a *Present address: Department of Zoology, University of Correspondence: Dr I. W. Henderson, Department of Manchester, Manchester M13 9PL, U.K.Zoology, University of Sheffield, Sheffield S10 2TN, U.K. male pattern of response was seen in hypophysectomized female rats.6. In both sexes PRA responses to ADH were blunted but not abolished by Padrenergic blockade (propranolol). a-Adrenergic blockade (phenoxybenzamine) had little influence on the male response but in females the typical increase disappeared so that ADH reduced PRA.7. It is concluded that pituitary hormones, including gonadotrophins and gonadal factors as well as adrenal sex steroids, appear to affect significantly the interplay between antidiuretic hormone and the renin-angiotensin system.

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Influence of the Pituitary Gland on Sodium Conservation, Plasma Renin and Renin Substrate Concentrations in the Rat

Cited by 27 publications

References 0 publications

The neuronal organization of the rat subfornical organ in vitro and a test of the osmo‐ and morphine‐receptor hypotheses.

The neuronal organization of the rat subfornical organ in vitro and a test of the osmo‐ and morphine‐receptor hypotheses.

A Method for the Measurement of Plasma Renin in the Rat

Vasopressin Effects on Plasma Renin Activity in Male and Female Rats

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