Ontogeny of surfactant apoprotein D, SP-D, in the rat lung.
Surfactant protein D (SP-D) is a collagenous surfactant-associated glycoprotein synthesized by alveolar type II cells. Antiserum against rat SP-D was raised in rabbits and an enzyme-linked immunosorbant assay (ELISA) has been developed using anti-rat SP-D IgG. In the present study we examined the developmental profile of SP-D in the rat lung compared with that of surfactant protein A (SP-A). SP-A content in the lungs increased during late gestation and reached its maximum on day 1 of neonate, and then gradually decreased until at least day 5. SP-D content during early gestation was less than 10 ng/mg protein until day 18, but on day 19 there was a 4-fold increase in SP-D (compared to that on day 18). It increased twice between day 21 and the day of birth, when it reached the adult level of 250 ng/mg protein, which is about one fourth that of the adult level of SP-A. Unlike SP-A there seemed to be no decrease in SP-D content after birth. These results demonstrate that SP-D is regulated developmentally as are the other components of surfactant, but the inconsistency in the developmental profiles of SP-A and SP-D suggests that these proteins may play different roles in lung maturation.
Ogasawara
Y
Y
Department of Biochemistry, Sapporo Medical College, Japan.
Kuroki
Y
Y
Shiratori
M
M
Shimizu
H
H
Miyamura
K
K
Akino
T
T
D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development; D001059:Apoproteins / Q000096:biosynthesis* / Q000276:immunology / Q000302:isolation & purification; D001992:Bronchoalveolar Lavage Fluid; D004591:Electrophoresis, Polyacrylamide Gel; D005314:Embryonic and Fetal Development; D004797:Enzyme-Linked Immunosorbent Assay; D007106:Immune Sera / Q000276:immunology; D015151:Immunoblotting; D008168:Lung / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000096:biosynthesis* / Q000276:immunology / Q000302:isolation & purification; D051381:Rats; D011919:Rats, Inbred Strains
D001059:Apoproteins; D007106:Immune Sera; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; C046616:pulmonary surfactant apoprotein