A method has been described that permits the measurement of the integrated concentration of growth hormone or any substance whose concentration in blood fluctuates widely. This method employs a small portable constant withdrawal pump with heparin-coated plastic cannula and tubing that are inserted intravenously through a disposable needle. Similar metabolic clearance rates (MCR) of 131I-HGH and nonradioactive HGH were found using a constant infusion technique. Changes in position, except for standing totally immovable, did not significantly alter the MCR, nor did it change the concentration of HGH. The true secretion rate of HGH was calculated in 4 normal female volunteers by multiplying their individual MCR of HGH by their integrated concentration of HGH. The secretion rates of HGH in these subjects ranged from 0.65 to 1.51 mg/24 hr. The secretion rate of HGH in an acromegalic patient was found to be 8.08 mg in 24 hr.
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Clinical Biochemistry
- Biochemistry, medical