Intramuscular Relative Dose Response (RDR) Determination of Liver Vitamin A Stores in Rats

• Published in: The Journal of nutrition Vol. 121; no. 2; pp. 187 - 191
• Main Authors: Zachman, Richard D., Chen, Xiaoming
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 01.02.1991; American Society for Nutritional Sciences
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Chromatography, High Pressure Liquid; Coenzymes, vitamins; Dose-Response Relationship, Drug; ESTADO NUTRICIONAL; ETAT NUTRITIONNEL; FOIE; Fundamental and applied biological sciences. Psychology; HIGADO; INJECTION; Injections, Intramuscular; intramuscular; INYECCION; liver; Liver - chemistry; Male; METHODE; METODOS; Other biological molecules; Random Allocation; RAT; RATA; Rats; Rats, Inbred Strains; relative dose response (RDR); RETINOL; Specific Pathogen-Free Organisms; Vitamin A - administration & dosage; Vitamin A - analogs & derivatives; Vitamin A - analysis; Vitamin A - blood; Vitamin A - pharmacokinetics; retinol; intramuscular; relative dose response (RDR); rats; liver; Methodology; Rat; Liver; Rodentia; Vitamin; Concentration; Intramuscular administration; Blood plasma; Retinol; Vertebrata; Mammalia; Kinetics; Measurement method; Biological accumulation; Nutritional status
• ISSN: 0022-3166; 1541-6100
• DOI: 10.1093/jn/121.2.187

This study questioned whether the relative dose response (RDR) method to detect liver stores of vitamin A could be used by intramuscular administration of the vitamin. Vitamin A-deficient and reference rat serum retinol levels were determined by HPLC at zero time and then again 5 h after an intramuscular injection of 5.25 µmol/kg retinyl palmitate. The RDR percentage was calculated: [(A5-A0)/(A5)] × 100. The 5-h RDR was determined in 20 deficient and 16 reference diet rats and a clear relationship to liver retinyl palmitate concentration was demonstrated. At a liver retinyl palmitate concentration of < 0.105 µmol/g, all RDR values were > 20%. When the liver retinyl palmitate was > 0.122 µmol/g the RDR was < 20%. This study suggests that the intramuscular RDR is a valid tool for estimating liver retinyl palmitate in populations in which the oral RDR cannot be administered.