Renin secretion by fetal lamb kidneys in vitro
Rawashdeh, N.M.; Rose, J.C.; Kerr, D.R.
American Journal of Physiology 258(2 Pt 2): R388-R392
1990
ISSN/ISBN: 0002-9513 PMID: 2155545 Document Number: 359613
We studied the content and secretion of renin by renal cortical slices obtained from ovine fetuses at 0.62-0.77 gestation (n = 5 immature) and at 0.84-1.00 gestation (n = 5 mature). Renin content of fresh slices and renin secretion after the incubation of slices in Robinson's medium with or without isoproterenol or dibutyryl (DB) adenosine 3',5'-cyclic monophosphate (cAMP) (10-4-10-8 M) were measured. Renin content of immature fetal kidneys (ng .cntdot. ml homogenate-1 .cntdot. h-1 .cntdot. mg-1) and basal renin secretion rate [ng (ANG I/h) .cntdot. mg tissue-1 .cntdot. h incubation-1] were 24.3 .+-. 3.0 and 1.4 .+-. 0.4, respectively. Both of these values were significantly lower (P < 0.02) than the corresponding results obtained with mature fetal kidneys (67.0 .+-. 4.5 and 3.4 .+-. 0.5). Renin content and basal secretion rates were strongly correlated (r = 0.78, P < 0.01). The addition of isoproterenol or DBcAMP induced a significant increase in renin secretion only when incubated with slices from mature fetuses. We conclude that there is a deficit in the .beta.-adrenoceptor-mediated renin release distal to cAMP formation in immature fetuses, which may be related to low renal content of renin at this stage of development.