Expression of transcripts related to intestinal ion and nutrient absorption in pregnant and lactating rats as determined by custom-designed cDNA microarray.

In pregnancy and lactation, maternal adaptation for the enhancement of intestinal ion and nutrient absorption is of paramount importance for fetal development and lactogenesis. This nutrient hyperabsorption has been reported to result from upregulation of transporter gene expression, in part, under control of lactogenic hormone prolactin (PRL). Since a number of gene families are responsible for ion and nutrient transport in the rat small intestine, we herein developed a custom-designed cDNA microarray (CalGeneArray) to determine the transcriptome responses of duodenal epithelial cells during these reproductive periods, which was subsequently validated by quantitative real-time PCR. We thus designed 277 oligonucleotide probes to detect 113 transcripts related to ion/nutrient transport, bone/calcium metabolism, paracrine regulator, and cell metabolism. Pregnancy was found to upregulate the expressions of several duodenal transporters, e.g., Trpm6, Trpm7, Glut5, and Trpv6. Pregnant rats subjected to 7-day injection of bromocriptine, an inhibitor of PRL release, showed the increased levels of some other transcripts, e.g., insulin-2 and Cyp27b1, compared to untreated pregnant rats. Bromocriptine also increased the mRNA levels of insulin-2, glucose transporter-1 (Sglt1), and Cyp27b1, while decreasing those of Fgfr2c, Atp1b2, and Cldn19 in early lactation. During late lactation, the levels of eight studied transcripts (i.e., NaPi-IIb, Cyp27b1, Cldn18, Casr, Atp1b2, Xpnpep, Pept1, and Trpm7) were altered. In conclusion, the CalGeneArray was powerful to help reveal that pregnancy and lactation modulated the expression of genes related to duodenal nutrient transport and cell metabolism. Our findings supported the physiological significance of PRL in regulating nutrient absorption during pregnancy and lactation.