Racial Differences in Phosphorus Metabolism

The investigators aim to study potential racial differences in renal phosphorus handling by provocatively testing urinary phosphorus excretion using parathyroid hormone infusions in healthy white volunteers compared to healthy black volunteers.

Study Overview

• Status: Completed
• Conditions: Control
• Intervention / Treatment: Drug: 1-34 parathyroid infusion

• Study Type: Interventional
• Enrollment (Actual): 26
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Florida
    • Miami, Florida, United States, 33136
      • University of Miami

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• 18 years of age or older
• Body mass index (BMI) within 20% ideal for their age and gender

Exclusion Criteria:

• Abnormal urinalysis
• Pregnancy or breast-feeding
• Medical conditions impacting phosphorus metabolism-primary hyperparathyroidism; diabetes mellitus; gastrointestinal malabsorption disorders; hyper- or hypothyroidism
• Medications known to affect phosphorus metabolism- current use of phosphorus supplements, phosphorus binders, calcitriol or calcitriol analogues, regular antacid or laxative use, calcitonin, etidronate, anticonvulsants
• Hyper- or hypophosphatemia (≥ 4.6 mg/dl or ≤ 2.5 mg/dl respectively), hyper- or hypocalcemia (≥ 10.6 or ≤ 8.5 mg/dl respectively), or severe anemia (Hgb < 8 g/dl for women and < 9 g/dl for men)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: PTH infusion; (1-34) PTH infusion at a rate of 0.055 ug/kg/hour for six hours	Drug: 1-34 parathyroid infusion; 1-34 parathyroid infusion at 0.055 mcg/kg/hr for 6 hours

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Urinary Phosphorus Excretion	Fractional excretion of phosphorus (the fraction of phosphorus filtered by the kidney which is excreted in the urine)	six hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fibroblast Growth Factor 23	The change in fibroblast growth factor 23 concentrations from baseline to six hours	six hours
Serum Phosphorus	change in serum phosphorus from baseline to six hours	six hours
Serum Calcium	change in serum calcium from baseline to six hours	six hours
Parathyroid Hormone	change in parathyroid hormone from baseline to six hours	six hours
Fractional Excretion of Calcium	change in urinary fractional excretion of calcium from baseline to six hours	six hours

Collaborators and Investigators

• Sponsor: University of Miami
• Collaborators: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK); National Institutes of Health (NIH)
• Investigators: Principal Investigator: Orlando M Gutierrez, MD, MMSc, University of Miami

Publications and helpful links

General Publications

• Gutierrez OM, Smith KT, Barchi-Chung A, Patel NM, Isakova T, Wolf M. (1-34) Parathyroid hormone infusion acutely lowers fibroblast growth factor 23 concentrations in adult volunteers. Clin J Am Soc Nephrol. 2012 Jan;7(1):139-45. doi: 10.2215/CJN.06240611.

Study record dates

Study Major Dates

• Study Start: February 1, 2009
• Primary Completion (Actual): June 1, 2011
• Study Completion (Actual): June 1, 2011

Study Registration Dates

• First Submitted: March 4, 2009
• First Submitted That Met QC Criteria: March 5, 2009
• First Posted (Estimate): March 6, 2009

Study Record Updates

• Last Update Posted (Actual): September 11, 2017
• Last Update Submitted That Met QC Criteria: September 5, 2017
• Last Verified: September 1, 2017

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Calcium-Regulating Hormones and Agents; Parathyroid Hormone
• Other Study ID Numbers: 20080669; K23DK081673 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No