A Comparison of the Effect of Hypothyroidism on Pressure Natriuresis in Male Wistar Kyoto (WKY) Rats and Spontaneously Hypertensive Rats (SHR)

Presenter Information

Jessa Gute, Minnesota State University - Mankato

Location

CSU Ballroom

Start Date

20-4-2015 10:00 AM

End Date

20-4-2015 11:30 AM

Student's Major

Biological Sciences

Student's College

Science, Engineering and Technology

Mentor's Name

David Sharlin

Mentor's Email Address

david.sharlin@mnsu.edu

Mentor's Department

Biological Sciences

Mentor's College

Science, Engineering and Technology

Second Mentor's Name

Penny Knoblich

Second Mentor's Email Address

penny.knoblich@mnsu.edu

Second Mentor's Department

Biological Sciences

Second Mentor's College

Science, Engineering and Technology

Description

Almost 1 billion people worldwide suffer from hypertension, or high blood pressure. Studies indicate hypothyroidism, starting at weaning, is associated with a decrease in systolic pressure in the Spontaneously Hypertensive Rat (SHR). Additionally, it has been determined that thyroid hormones are critical in the synthesis of nitric oxide. Nitric oxide (NO) is required for normal urinary sodium elimination in response to a rise in blood pressure (pressure natriuresis). The production of nitric oxide is impaired in patients with hypertension, a condition referred to as endothelial dysfunction. Nitric oxide inhibition results in a marked decrease in pressure natriuresis in male rats. Impaired pressure natriuresis, is observed in all instances of hypertension. However, past studies found no impact of hypothyroidism on the pressure natriuresis response. This study sought to determine the relationship between developmental hypothyroidism and changes in pressure natriuresis in Spontaneously Hypertensive Rats (SHRs) and their parent strain, the normotensive (normal blood pressure) Wistar Kyoto Rat (WKY). This was accomplished through monitoring acute changes in urinary sodium excretion in response to a rise in blood pressure in control and hypothyroid, SHR and WKY male rats. All experimental groups exhibited a comparable resting mean arterial pressure (MAP) and a comparable increase in mean arterial pressure resulting from artery ligation. Interestingly, only hypothyroid WKYs exhibited a significantly greater increase in sodium excretion with an increase in MAP compared to their control counterparts. Comparable urine volume excretion was observed in all groups. These results indicate a strain specific response in pressure natriuresis to hypothyroidism.