ROLE OF THE THYROID GLAND IN DEVELOPMENT AND MAINTENANCE OF RENAL HYPERTENSION IN RATS

ABSTRACT The anti-thyroid drugs, thiouracil, propylthiouracil, and methimazole, prevented both development of elevated blood pressure and cardiac hypertrophy usually accompanying kidney encapsulation with latex envelopes. These drugs also reduced elevated blood pressure of rats with hypertension of 13 to 40 weeks' duration prior to drug administration. Addition of desiccated thyroid powder to diet containing an anti-thyroid drug overcame the anti-hypertensive effect of the latter. Withdrawal of thyroid powder only was followed by return of blood pressure to previous low level within 3 weeks. The results suggest that the anti-hypertensive effect of these drugs is related directly to the hypothyroidism produced rather than to extrathyroidal effects of the drugs. Comparison of potencies of the 3 drugs in terms of anti-hypertensive effect, inhibition of growth rate, increase in testicular size, and increase in thyroid size suggests that propylthiouracil and methimazole are equally potent per unit weight of drug. Thiouracil has approximately half the potency of the other two.

Download Full-text

Role of community health volunteers in identifying people with elevated blood pressure for diagnosis and monitoring of hypertension in Malawi: a qualitative study

BMC Cardiovascular Disorders ◽

10.1186/s12872-021-02171-7 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Elvis Safary ◽

Micrina Mwandeti ◽

Beatrice Matanje ◽

Claudia Beiersmann ◽

Caroline Mtaita ◽

...

Keyword(s):

Blood Pressure ◽

Community Health ◽

Communicable Diseases ◽

Health Facilities ◽

Elevated Blood Pressure ◽

Elevated Blood ◽

Structured Interviews ◽

Community Health Volunteers ◽

Provision Of Services

Abstract Background In recent years, there has been greater recognition of the important role of community health volunteers in many countries and their important role informs many health programs. This include health education, provision of services such as screening, monitoring and referral to health facilities. Their roles are better understood in the areas of communicable diseases like HIV infection, Tuberculosis and Malaria however little is known about their role in non-communicable diseases. This study seeks to explore perception of CHVs’ functions, tasks, and their fulfilment in identifying people with elevated blood pressure for diagnosis and monitoring of hypertension in Lilongwe, Malawi. Methods This was a qualitative naturalistic research design utilizing observation and semi-structured interviews with community health volunteers working in Lilongwe, Malawi. Interviews were carried out with the researcher. Participants were recruited from the ZaMaC project. An interview guide was developed with a category-guided deductive approach. The interviews were recorded through note taking. Data analysis was performed using content analysis approach. Results Community health volunteers have multiple roles in prevention and monitoring of hypertension. They act as health educators and provide lifestyle counselling. They screened for hypertension and monitored blood pressure and assisted community members to navigate the health system such as linkage to health facilities. These roles were shaped in response to community needs. Conclusion This study indicates the complexities of the roles of community health volunteer in identifying people with elevated BP for diagnosis and monitoring of hypertension. Understanding community health volunteers’ roles provides insight into their required competencies in provision of their daily activities as well as required training to fill in their knowledge gaps.

Download Full-text

Role of Autonomic Nervous System in Maintenance of Cerebral and Renal Hypertension

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1957.188.2.371 ◽

1957 ◽

Vol 188 (2) ◽

pp. 371-374 ◽

Cited By ~ 2

Author(s):

Sol Rothman ◽

Douglas R. Drury

Keyword(s):

Blood Pressure ◽

Nervous System ◽

Autonomic Nervous System ◽

Renal Hypertension ◽

The Other ◽

Peripheral Vasculature ◽

Blood Pressures ◽

Sympathetic Nervous ◽

Blood Pressure Responses

The blood pressure responses to various drugs were investigated in renal hypertensive, cerebral hypertensive and normotensive rabbits. Hexamethonium bromide and Dibenamine reduced the blood pressures of renal and cerebral hypertensives. Effects in the normal were insignificant. The cerebral hypertensive's blood pressure was slightly affected by benzodioxane. Blood pressure was not reduced at all in the other groups. Blood pressure of the renal hypertensive rabbit was greatly reduced by Veriloid and dihydroergocornine. Blood pressures of cerebral and normal animals were affected to a lesser degree. The results suggest that maintenance of hypertension in the cerebral hypertensive rabbit depends on an overactive sympathetic nervous system, possibly due to the release of medullary pressor centers from inhibitory impulses originating in higher centers; whereas, the maintenance of hypertension in the renal hypertensive rabbit may be attributed to an increased reactivity of the peripheral vasculature to a normal sympathetic tone.

Download Full-text

Nitric oxide synthase-mediated blood pressure regulation in obese melanocortin-4 receptor-deficient pregnant rats

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00285.2016 ◽

2016 ◽

Vol 311 (5) ◽

pp. R851-R857 ◽

Cited By ~ 3

Author(s):

Frank T. Spradley ◽

Jennifer M. Sasser ◽

Jacqueline B. Musall ◽

Jennifer C. Sullivan ◽

Joey P. Granger

Keyword(s):

Nitric Oxide ◽

Blood Pressure ◽

Mesenteric Arteries ◽

Elevated Blood Pressure ◽

Pressure Regulation ◽

Elevated Blood ◽

Pregnant Rats ◽

Melanocortin 4 Receptor ◽

Regulation Of Blood Pressure

Although obesity increases the risk for hypertension in pregnancy, the mechanisms responsible are unknown. Increased nitric oxide (NO) production results in vasodilation and reduced blood pressure during normal pregnancy in lean rats; however, the role of NO is less clear during obese pregnancies. We examined the impact of obesity on NO synthase (NOS)-mediated regulation of blood pressure during pregnancy by testing the hypothesis that NOS activity, expression, and regulation of vascular tone and blood pressure are reduced in obese pregnant rats. At gestational day 19, melanocortin-4 receptor (MC4R)-deficient obese rats (MC4R) had greater body weight and fat mass with elevated blood pressure and circulating sFlt-1 levels compared with MC4R pregnant rats. MC4R pregnant rats also had less circulating cGMP levels and reduced total NOS enzymatic activity and expression in mesenteric arteries. Despite decreased biochemical measures of NO/NOS in MC4R rats, NOS inhibition enhanced vasoconstriction only in mesenteric arteries from MC4R rats, suggesting greater NOS-mediated tone. To examine the role of NOS on blood pressure regulation in obese pregnant rats, MC4R and MC4R pregnant rats were administered the nonselective NOS inhibitor NG-nitro-l-arginine methyl ester (l-NAME, 100 mg/l) from gestational day 14 to 19 in drinking water. The degree by which l-NAME raised blood pressure was similar between obese and lean pregnant rats. Although MC4R obese pregnant rats had elevated blood pressure associated with reduced total NOS activity and expression, they had enhanced NOS-mediated attenuation of vasoconstriction, with no evidence of alterations in NOS-mediated regulation of blood pressure.

Download Full-text

Abstract P040: Role of 20-HETE in Elevated Blood Pressure in Hyperandrogenemic Female Rats, a Model of Polycystic Ovarian Syndrome

Hypertension ◽

10.1161/hyp.66.suppl_1.p040 ◽

2015 ◽

Vol 66 (suppl_1) ◽

Author(s):

Chetan N Patil ◽

Carolina Dalmasso ◽

Rodrigo O Maranon ◽

Huimin Zhang ◽

Richard J Roman ◽

...

Keyword(s):

Blood Pressure ◽

Polycystic Ovary ◽

Premenopausal Women ◽

Female Rats ◽

Elevated Blood Pressure ◽

Female Rat ◽

Elevated Blood ◽

Reproductive Disorder ◽

Consomic Strain

Polycystic ovary syndrome (PCOS) is the most common reproductive disorder in premenopausal women, is characterized by hyperandrogenemia, metabolic syndrome and inflammation. They also exhibit elevated blood pressure (BP) but may not be treated since they do not meet the criteria for hypertension (BP>130/90 mm Hg). We have characterized a female rat model of hyperandrogenemia (HAF) using dihydrotestosterone (DHT) that mimics many characteristics of women with PCOS. In the present study we tested the hypothesis that androgen-induced upregulation of the cytochrome P450 4A2 isoform (CYP4A2) and the formation of 20-hydroxyeicosatetraenoic acid (20-HETE) in renal microvasculature contributes to the elevated BP in HAF rats. Female rats of SS.5BN consomic strain (wild type) rats and CYP4A2-/- rats on this same background were implanted with DHT (7.5mg/90d) or placebo pellets (n=5-8/grp) beginning at 6 wks of age; pellets were changed every 85 d. At 14 wks of age, rats were implanted with radiotelemetry transmitters, and mean arterial pressure (MAP) was measured for 10 days. Endogenous 20-HETE levels were measured using LC-MS in renal microvessels isolated using an Evans Blue sieving technique. DHT-treated HAF-SS.5BN rats had significantly higher MAP compared to placebo-SS.5BN (128±6 vs. 104±1 mmHg, p<0.004). In contrast, HAF-CYP4A2-/- rats had no change in MAP compared to placebo-CYP4A2-/- controls (120±4 vs 118±3 mmHg, p=NS). Endogenous 20-HETE levels in renal microvessels of HAF-SS.5BN rats were significantly increased compared to Placebo-SS.5BN (2.27±0.91 vs. 0.32±0.037 pmol/mg, p<0.01). The 20-HETE levels were lower in CYP4A2-/- than SS.5BN but DHT in HAF-CYP4A2-/- had no effect on 20-HETE levels compared to Placebo- CYP4A2-/-. These results suggest that androgen-mediated upregulation of the expression of CYP4A2 and the production of 20-HETE in renal microvessels contribute to elevated BP in HAF rats. These data also suggest that methods to attenuate 20-HETE may provide a novel therapeutic to reduce BP in women with PCOS. Work supported by NIH RO1HL66072 and PO1HL51971.

Download Full-text

Response to Fujisawa: Elevated blood pressure in different populations: the role of dietary salt consumption

Hypertension Research ◽

10.1038/hr.2012.111 ◽

2012 ◽

Vol 35 (9) ◽

pp. 961-962

Author(s):

Huynh Long Quan ◽

Christopher Leigh Blizzard ◽

Alison Jane Venn ◽

James Edward Sharman

Keyword(s):

Blood Pressure ◽

Elevated Blood Pressure ◽

Elevated Blood ◽

Dietary Salt ◽

Salt Consumption ◽

Different Populations

Download Full-text

A3672 Role of waist circumference in predicting elevated blood pressure among children and adolescents with normal body mass index

Journal of Hypertension ◽

10.1097/01.hjh.0000549184.63892.12 ◽

2018 ◽

Vol 36 ◽

pp. e290

Author(s):

Mingming Wang ◽

Jiahong Sun ◽

Chuanwei Ma ◽

Bo Xi

Keyword(s):

Blood Pressure ◽

Body Mass Index ◽

Waist Circumference ◽

Children And Adolescents ◽

Body Mass ◽

Elevated Blood Pressure ◽

Normal Body Mass Index ◽

Elevated Blood ◽

Normal Body

Download Full-text

The moderating role of proactive coping on the relationship between distress tolerance and elevated blood pressure

Journal of Psychology in Africa ◽

10.1080/14330237.2019.1616426 ◽

2019 ◽

Vol 29 (3) ◽

pp. 243-248

Author(s):

Maria Chidi C. Onyedibe

Keyword(s):

Blood Pressure ◽

Distress Tolerance ◽

Proactive Coping ◽

Elevated Blood Pressure ◽

Elevated Blood ◽

The Relationship ◽

Moderating Role

Download Full-text

Abstract 246: Role Of Cytochrome P450 4a2 In Mediating The Elevated Blood Pressure In A Rat Model Of Polycystic Ovary Syndrome

Hypertension ◽

10.1161/hyp.64.suppl_1.246 ◽

2014 ◽

Vol 64 (suppl_1) ◽

Author(s):

Rodrigo O Maranon ◽

Chetan N Patil ◽

Carolina Dalmasso ◽

Richard Roman ◽

Jane F Reckelhoff

Keyword(s):

Blood Pressure ◽

Cytochrome P450 ◽

Polycystic Ovary Syndrome ◽

Polycystic Ovary ◽

Female Rats ◽

Elevated Blood Pressure ◽

Elevated Blood ◽

Renal Vasculature ◽

Ovary Syndrome

Women with polycystic ovary syndrome (PCOS) often have elevated blood pressure (BP). PCOS is characterized in part by increases in androgens, and androgens can increase cytochrome P450 (CYP) 4A isoforms and 20-HETE synthesis. We have found that CYP4A2 expression is increased in renal vasculature of hyperandrogenemic female rats, a model of PCOS. In the present study we tested the hypothesis that androgen increase would not cause elevated BP in CYP4A2 -/- rats compared with wild type SS.Bn5 rats. CYP4A2 -/- and SS.Bn5 rats (n=6-8/grp) were treated from 4 wks of age with dihydrotestosterone pellets (DHT 7.5 mg/90 d) or placebo pellets until 14 wks, and then telemetry transmitters were implanted. After 2 wks, mean arterial pressure (MAP) was measured for 10 days. DHT increased MAP and decreased HR in SS.Bn5 compared with placebo controls (placebo: 104±2 vs. DHT: 126±6 mmHg, p<0.001). In contrast, while placebo-treated CYP4A2 -/- rats had higher MAP than WT, DHT did not increase BP in CYP4A2 -/- rats (Placebo: 120±1 vs. DHT: 118±1 mmHg, p=NS). These data suggest that CYP4A2 may be necessary for DHT to increase BP in our model of PCOS. However, by what mechanism(s) CYP4A2 -/- rats have higher MAP than SS.Bn5 WT remains to be determined. Supported by NIH R01HL66072, P01HL05971 and AHA 14POST18640015.

Download Full-text