Calbindin-D9k gene expression during the perinatal period in the rat: correlation to estrogen receptor expression in uterus.
Calbindin-D9k (CaBP-9k) is a cytosolic calcium binding protein mainly expressed in duodenum, placenta and uterus. The gene encoding the rat CaBP-9k is subject to tissue specific induction by 1,25 dihydroxyvitamin D3 (intestine) and estradiol (E2) (uterus). Control of placental expression remains unknown. The expression of CaBP-9k mRNA during the perinatal period was studied (pregnancy day 21 (P21)-lactation day 4 (L4)). In uterus, maximal expression levels were found at P21 and maintained until L1. With the transition to L2, the CaBP-9k mRNA concentration dropped drastically below the detection limit as quantitated by Northern blot analysis. Measurements of E2 and progesterone (P) levels showed a gradual decrease at late pregnancy (P21; birth). Post partum E2 levels continued to decline and P concentrations increased slightly. Uterine estrogen receptor (ER) mRNA levels determined by cDNA/PCR analysis revealed close correlation between expression of ER and CaBP-9k mRNAs. ER mRNA levels were maximal at P22 and declined at parturition and with onset of lactation. At L2 and L3 ER mRNA levels were minimal and had decreased 5-fold compared to late pregnancy. CaBP-9k protein concentrations fluctuated only slightly dependent on the stage of the estrous cycle: estrus > proestrus > diestrus. During the perinatal period CaBP-9k concentration was overall lower than in non-pregnant uterus and revealed only a moderate increase at birth and decrease in early lactation. Similar to the uterine levels, placental CaBP-9k mRNA was highest at P21 and remained high until birth. Fetal duodenal CaBP-9k rose sharply just prior to birth and plateaued in the early postpartal period.(ABSTRACT TRUNCATED AT 250 WORDS)
Krisinger
J
J
Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, Canada.
Dann
J L
JL
Applegarth
O
O
Currie
W D
WD
Jeung
E B
EB
Staun
M
M
Leung
P C
PC
D000818:Animals; D001483:Base Sequence; D064026:Calbindins; D002117:Calcitriol / Q000494:pharmacology; D004386:Duodenum / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D004790:Enzyme Induction; D004958:Estradiol / Q000097:blood / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation; D005865:Gestational Age; D008297:Male; D008969:Molecular Sequence Data; D010920:Placenta / Q000378:metabolism; D011374:Progesterone / Q000097:blood; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000096:biosynthesis / Q000235:genetics*; D064030:S100 Calcium Binding Protein G / Q000096:biosynthesis / Q000235:genetics*; D014599:Uterus / Q000378:metabolism*
D064026:Calbindins; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D064030:S100 Calcium Binding Protein G; C576508:S100g protein, rat; D011374:Progesterone; D004958:Estradiol; D002117:Calcitriol