Modulation of binding characteristics of peripheral benzodiazepine receptors in vitamin A-deficient guinea pig lung.
Both vitamin A and peripheral benzodiazepine receptors (PBRs) are involved in the control of cell proliferation and differentiation. The objective of this study was to determine whether vitamin A deficiency causes any modulation in the binding characteristics of the PBRs. Forty-five weanling guinea pigs were divided into three groups (control, pair-fed control, and vitamin A-deficient). Vitamin A-deficiency status was achieved after 90 days of feeding. It caused atelectasis, hyperplasia and metaplasia of alveolar epithelium, acute inflammation of the tracheobronchial tree, and a significant increase in the number of alveolar type II cells. In comparison to the control and pair-fed control groups, the lung of vitamin A-deficient animals had 40.6 and 42.8% less PBR density, respectively. There was no significant difference in the equilibrium dissociation constant (KD) of PBRs between the control and the pair-fed control groups, whereas the KD value was 77.7 and 60% higher in the vitamin A-deficient groups than in the control and the pair-fed control groups, respectively. Furthermore, vitamin A-deficiency caused a decrease in the binding capacity of PBRs in both nuclear and mitochondrial fractions. These results may suggest a close functional relationship between vitamin A and PBRs.
Nayyar
T
T
Department of Biochemistry, Meharry Medical College, Nashville, TN 37208, USA.
Mukherjee
S
S
Das
S K
SK
D000818:Animals; D001570:Benzodiazepinones / Q000378:metabolism; D006168:Guinea Pigs; D008168:Lung / Q000378:metabolism* / Q000473:pathology; D008297:Male; D011869:Radioligand Assay; D011963:Receptors, GABA-A / Q000378:metabolism*; D014316:Tritium; D014802:Vitamin A Deficiency / Q000378:metabolism*
D001570:Benzodiazepinones; D011963:Receptors, GABA-A; D014316:Tritium; C028513:4'-chlorodiazepam