Haviv Y S, Wald H, Garty H, Popovtzer M M
Nephrology Service, Hadassah Hebrew University Hospital, Jerusalem, Israel.
Pediatr Nephrol. 1998 Sep;12(7):540-4. doi: 10.1007/s004670050501.
Recently, an IsK-like potassium (K+) channel corticosteroid-induced gene (CHIF) was cloned. A high-K+ diet enhances, while a low-K+ diet decreases the expression of this gene. The major expression of CHIF in the adult rat kidney is in the papilla, where it is constitutive, in contrast to its inducibility by corticosteroids and a low-salt diet in the rat colon. In order to further understand the ontogeny of K+ clearance, we studied the presence of CHIF in the kidney papilla in different stages of rat development. Total RNA from rat kidney papillae of 1- to 3-day pre-labor unborn offspring, 2- to 3-day-old newborns, 10-day-old, 6-week-old, and 43-week-old rats underwent northern hybridization for CHIF and the alpha-subunit of the Na+-K+-ATPase mRNA. Minor expression of CHIF mRNA was found in fetal and newborn rat papillae, while older rats showed an age-related increase in gene expression. The expression of the alpha-sub unit of the Na+-K+-ATPase was not age related. We conclude that CHIF is present in the rat kidney papilla and the expression is related to age. The relative deficiency of CHIF in the newborn may be one of the factors responsible for the reduced K+ clearance in is period.
最近，一种类IsK钾（K+）通道皮质类固醇诱导基因（CHIF）被克隆出来。高钾饮食可增强该基因的表达，而低钾饮食则会降低其表达。CHIF在成年大鼠肾脏中的主要表达部位是乳头，在该部位其表达是组成性的，这与它在大鼠结肠中受皮质类固醇和低盐饮食诱导的情况不同。为了进一步了解钾清除的个体发生情况，我们研究了大鼠发育不同阶段肾脏乳头中CHIF的存在情况。对1至3天临产前未出生的后代、2至3天大的新生儿、10天大、6周龄和43周龄大鼠的肾脏乳头总RNA进行了CHIF和Na+-K+-ATP酶mRNAα亚基的Northern杂交。在胎儿和新生大鼠乳头中发现CHIF mRNA表达较少，而年龄较大的大鼠基因表达呈年龄相关增加。Na+-K+-ATP酶α亚基的表达与年龄无关。我们得出结论，CHIF存在于大鼠肾脏乳头中，且表达与年龄相关。新生儿期CHIF的相对缺乏可能是该时期钾清除率降低的原因之一。
