Regulation of extra-renal renin during ontogeny.

Previous studies demonstrated that the level of renin in the male submandibular gland (SMG) of mouse strains that contain renin genes [e.g. Cr1:CD-1(1CR)BR] increased dramatically at puberty, but a less pronounced response was seen in the C57BL/10J (a strain that has a single renin gene). However, the expression of renin in kidney and other extrarenal tissues throughout growth and development has not been examined. In this study we characterized developmental changes in renal renin and certain extrarenal renin levels in the male and female CD-1 mouse and male C-57 mouse. Renal renin activity remains relatively constant throughout ontogeny in male and female CD-1 mice and in the C-57 male mouse. In the CD-1 male mouse, SMG renin levels vary during ontogeny, coincident with periods in growth and development that are associated with hormonal shifts. Glandular renin levels are higher in the neonatal period than at 2-3 weeks of age, and then rise dramatically with the onset of puberty. Renin levels in the adrenal and testis of the CD-1 male mouse follow a similar temporal pattern. However, this dramatic increase in gonadal, adrenal, and SMG renin in the CD-1 male mouse at puberty is not seen in the organs from the CD-1 female mouse or those of the C-57 male mouse. Taken together, the present results demonstrated that the expression of extrarenal sources of renin is under genetic and hormonal influences. In addition, our data suggest that control of extrarenal renin expression may differ from that of renal renin.