WordNet

(physical chemistry) a fourth state of matter distinct from solid or liquid or gas and present in stars and fusion reactors; a gas becomes a plasma when it is heated until the atoms lose all their electrons, leaving a highly electrified collection of nuclei and free electrons; "particles in space exist in the form of a plasma"
a green slightly translucent variety of chalcedony used as a gemstone
the colorless watery fluid of the blood and lymph that contains no cells, but in which the blood cells (erythrocytes, leukocytes, and thrombocytes) are suspended (同)plasm, blood_plasma
any specific behavior; "they avoided all recreational activity"
(chemistry) the capacity of a substance to take part in a chemical reaction; "catalytic activity"
a proteolytic enzyme secreted by the kidneys; catalyzes the formation of angiotensin and thus affects blood pressure

PrepTutorEJDIC

(また『blood plasma』)血漿,リンパ漿 / 原形質
〈U〉『活動』,働き;活力 / 《しばしば複数形で》(種々の)『活動』,行事;(学生の)学内(外)活動,クラブ活動 / 〈U〉(商況・市場などの)活発,活気

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/09/17 15:52:05」(JST)

wiki en

Plasma renin activity (PRA), also known as the renin (active) assay or random plasma renin, is a measure of the activity of the plasma enzyme renin, which plays a major role in the body's regulation of blood pressure, thirst, and urine output. PRA is sometimes measured, specially in case of certain diseases which present with hypertension or hypotension. PRA is also raised in certain tumors.^[1] A PRA measurement may be compared to a plasma aldosterone concentration as an aldosterone-to-renin ratio.

Measurement and Values

Measurement is done from a sample of venous blood using immunological measuring mechanisms like ELISA, RIA, etc. Often these are done by automated machines to minimize human error.

Considerations for variation

These values are quite variable in a normal person. Variation occur with the following:

Salt intake
Pregnancy
Time of the day
Body position (sitting, lying down)
State of water intake and dehydration
Use of anti-hypertensive drugs, estrogen-containing forms of hormonal contraception, anti-anginals drugs, etc. (basically, most drugs that are active on the heart, blood vessels and/or the kidneys.
Certain diseases of the heart, kidneys, etc.

Normal values

Reference ranges for blood tests of plasma renin activity can be given both in mass and in international units (μIU/mL or equivalently mIU/L, improperly shown as μU/mL or U/L, confusing mcU/mL used where Greek μ not available), with the former being roughly convertible to the latter by multiplying with 11.2.^[2] The following table gives the lower limit (2.5th percentile) and upper limit (97.5th percentile) for plasma renin activity by mass and MCU, with different values owing to various factors of variability of reference ranges:

Unit	Lower limit	Upper limit
ng/(mL*hour)	0.29,^[3] 1.9^[4]	3.7^[3]^[4]
μIU/mL	3.3,^[2] 21^[5]	41^[2]^[5]

Results and explanations

Please go through the physiology of renin and the renin-angiotensin system to understand why the following occur.

Higher-than-normal levels may indicate:^[6]^[7]^[8]^[9]^[10]

Disease	Brief Description
Addison's disease	Kidneys trying to counter low aldosterone output.
Cirrhosis of the liver	Reduced breakdown of Angiotensin.
Essential hypertension	Just more of renin is being secreted by the kidneys.
Hemorrhage (bleeding)	Kidneys trying to raise falling blood pressure.
Hypokalemia	Kidneys trying to raise falling blood pressure due to reduced cardiac output.
Malignant hypertension	Excessive renin is being secreted by the kidneys.
Renin-producing renal tumors	Tumors can secrete substances like this. See tumor markers
Renovascular hypertension	Renal vascular damage leading to reduced JGA perfusion.

Lower-than-normal levels may indicate:

Disease	Brief Description
ADH therapy	Leads to water retention and thus raised blood pressure.
Salt-retaining steroid therapy	see above
Salt-sensitive essential hypertension	see above
Primary Hyperaldosteronsim	see above and direct inhibition of aldosteron on renin secretion

References

^ Hamilton Regional Laboratory Medicine Program - Laboratory Reference Centre Manual. Renin Direct.
^ ^a ^b ^c New Assays for Aldosterone, Renin and Parathyroid Hormone University of Washington, Department of Laboratory Medicine. Retrieved Mars 2011
^ ^a ^b Converted from values in μIU/mL by dividing with a factor of 11.2 μIU/mL per ng/(mL*hour), as given in:
- New Assays for Aldosterone, Renin and Parathyroid Hormone University of
Washington, Department of Laboratory Medicine. Retrieved Mars 2011
^ ^a ^b Pratt, R.; Flynn, J.; Hobart, P.; Paul, M.; Dzau, V. (1988). "Different secretory pathways of renin from mouse cells transfected with the human renin gene". The Journal of Biological Chemistry 263 (7): 3137–3141. PMID 2893797. edit
^ ^a ^b Converted from values in ng/(mL*hour) by multiplying with a factor of 11.2 μIU/mL per ng/(mL*hour), as given in:
- New Assays for Aldosterone, Renin and Parathyroid Hormone University of
Washington, Department of Laboratory Medicine. Retrieved Mars 2011
^ Fujino T, Nakagawa N, Yuhki K, Hara A, Yamada T, Takayama K, Kuriyama S, Hosoki Y, Takahata O, Taniguchi T, Fukuzawa J, Hasebe N, Kikuchi K, Narumiya S and Ushikubi F. (2004) Decreased susceptibility to renovascular hypertension in mice lacking the prostaglandin I2 receptor IP. J. Clin. Invest. 114:805-812.
^ Human renin gene: structure and sequence analysis. 1984 Aug; PubMed Free text.
^ Cloning and sequence analysis of cDNA for human renin precursor. ; PubMed.
^ Pivotal role of the renin/prorenin receptor in angiotensin II production and cellular responses to renin. 2002 Jun; PubMed.
^ Different secretory pathways of renin from mouse cells transfected with the human renin gene. 1988 Mar 5; PubMed Free text.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 副腎疾患におけるレニン-アンギオテンシン-アルドステロン系の評価 assays of the renin angiotensin aldosterone system in adrenal disease
2. 低カリウム血症を合併した高血圧症へのアプローチ approach to the patient with hypertension and hypokalemia
3. 腎移植におけるHLAとABOの感作および脱感作 hla and abo sensitization and desensitization in renal transplantation
4. 成人における高血圧の初期評価 initial evaluation of the hypertensive adult
5. 治療抵抗性高血圧の定義、危険因子、および評価 definition risk factors and evaluation of resistant hypertension

English Journal

β-Blocker withdrawal is preferable for accurate interpretation of the aldosterone-renin ratio in chronically treated hypertension.

Browne GA1, Griffin TP1,2, O'Shea PM3, Dennedy MC1,2.
Clinical endocrinology.Clin Endocrinol (Oxf).2016 Mar;84(3):325-31. doi: 10.1111/cen.12882. Epub 2015 Sep 22.
OBJECTIVES: To evaluate the effects of β-adrenoreceptor antagonists (β-blockers) on the aldosterone-renin ratio (ARR) in the context of antihypertensive polypharmacy in chronic hypertension. To determine the optimal duration of β-blocker withdrawal required to normalize the ARR.DESIGN: A prospect
PMID 26300226

Neural Control of Blood Pressure in Chronic Intermittent Hypoxia.

Shell B1, Faulk K1, Cunningham JT2.
Current hypertension reports.Curr Hypertens Rep.2016 Mar;18(3):19. doi: 10.1007/s11906-016-0627-8.
Sleep apnea (SA) is increasing in prevalence and is commonly comorbid with hypertension. Chronic intermittent hypoxia is used to model the arterial hypoxemia seen in SA, and through this paradigm, the mechanisms that underlie SA-induced hypertension are becoming clear. Cyclic hypoxic exposure during
PMID 26838032

Association Between Pituitary-Adrenal Axis Dominance Over the Renin-Angiotensin-Aldosterone System and Hypertension.

Daimon M1, Kamba A1, Murakami H1, Takahashi K1, Otaka H1, Makita K1, Yanagimachi M1, Terui K1, Kageyama K1, Nigawara T1, Sawada K1, Takahashi I1, Nakaji S1.
The Journal of clinical endocrinology and metabolism.J Clin Endocrinol Metab.2016 Mar;101(3):889-97. doi: 10.1210/jc.2015-3568. Epub 2016 Jan 5.
CONTEXT: The hypothalamus-pituitary-adrenal (HPA) axis and the renin-angiotensin aldosterone system (RAAS) are well known to be associated with hypertension. However, the extent of the effects is not yet well elucidated in general conditions.OBJECTIVE: To separately determine the effect of the HPA a
PMID 26731257