Diagnosing Natriuretic Peptide Deficiency

Diagnosing Natriuretic Peptide Deficiency: A Pilot Study

In this pilot study, the investigators will determine the response of the natriuretic peptide (NP) hormone system after a dose of intravenous dexamethasone (a steroid medication). The goal of the proposed project is to generate preliminary data that will be used to develop power calculations, inform cutoff ranges, and inform the timing of the NP response for larger subsequent studies.

Aim: To determine the range of distribution and time course of natriuretic peptide (NP) responses to a single dose of dexamethasone IV 4 mg in healthy lean individuals.

Hypothesis: Determination of the NP responses (the range and time course of changes in NP levels) to dexamethasone in 10 healthy individuals will inform the time course and frequency of blood sampling in a definitive prospective study, as well as enable investigators to perform a sample size calculation for a definitive prospective study.

see above

Inclusion criteria:

• Men and women ages 18-50 years
• BMI 18.5 to <25 kg/m^2

Exclusion Criteria:

• Significant use of systemically-absorbed glucocorticoids currently or for an extended period of time during the prior 6 months
• Current use of antihypertensive medications
• Current use of metformin, or any antidiabetic medications (which could affect glucose and insulin levels)
• Current use of medications known to affect dexamethasone metabolism, including phenytoin, rifampin, carbamazepine, troglitazone, and barbiturates
• Active, clinically significant infection at time of visit
• History of adrenal insufficiency or Cushing's syndrome
• Prior or current cardiovascular disease, renal disease, or liver disease
• Diabetes mellitus, pre-diabetes, impaired fasting glucose, or impaired glucose tolerance
• Atrial fibrillation
• Bleeding disorder or anemia
• Elevated Liver Functions Tests > 2 times upper limit of normal
• Estimated glomerular filtration rate < 60 ml/min
• HbA1c > 5.7
• Abnormal sodium or potassium level
• Positive pregnancy test, women of child-bearing age not practicing birth control, women who are breastfeeding