Effect of DMBA on the expression of prolactin receptors and IGF1 genes in rat mammary gland.
Prolactin receptor and IGF1 gene expression were measured in mammary glands from Sprague-Dawley rats at different times (10, 30; and 58 d) after administration of a single dose of 15 mg dimethylbenz(a)-anthracene (DMBA) per os at 55 d of age, and in DMBA-induced mammary tumors appearing in these rats at approximately 2 months after DMBA administration; The relative gene expression of prolactin receptor and insulin-like growth factor (IGF1) mRNAs was measured by hybridization to Northern blots prepared from pools of tissue. The probes used were 32P-labelled cDNAs specific to the extracellular domain of the receptor (E probe), common to all forms, and a probe specific to the intracellular position of the long form of the receptor (I probe), a human IGF1 probe, and chicken beta-actin probe, to correct for loss of tissue and different metabolic activity of the tissues. Hybridization with the prolactin receptor probes revealed bands at 2.5, 3; and 5.5 kb hybridizing with the long form of the receptor and a more intense band at 1.8 kb that corresponded to the short form of the receptor. There were no changes in the relative expression of prolactin receptor mRNAs in the mammary gland of control (oil-treated) or DMBA-treated rats, although there was a gradual diminution of expression with increasing age of the animals. In contrast, in DMBA-induced mammary tumors, there was a marked increase in the relative expression of prolactin receptor mRNAs with, however, no modification in the relative proportion of short and long forms.(ABSTRACT TRUNCATED AT 250 WORDS)
Jahn
G A
GA
Laboratorio de Reproduccion y Lactancia, Cricyt-Conicet, Mendoza, Argentina.
Diolez-Bojda
F
F
Belair
L
L
Kerdelhué
B
B
Kelly
P A
PA
Djiane
J
J
Edery
M
M
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000494:pharmacology*; D000367:Age Factors; D000818:Animals; D015152:Blotting, Northern; D005260:Female; D015870:Gene Expression / Q000187:drug effects*; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008321:Mammary Glands, Animal / Q000737:chemistry*; D008325:Mammary Neoplasms, Experimental / Q000235:genetics; D051381:Rats; D011919:Rats, Inbred Strains; D011972:Receptor, Insulin / Q000235:genetics*; D011981:Receptors, Prolactin / Q000235:genetics*
D011981:Receptors, Prolactin; D015127:9,10-Dimethyl-1,2-benzanthracene; D007334:Insulin-Like Growth Factor I; D011972:Receptor, Insulin