Effects of growth hormone and pregnancy on expression of growth hormone receptor, insulin-like growth factor-I, and insulin-like growth factor binding protein-2 and -3 genes in bovine uterus, ovary, and oviduct.
The effects of growth hormone (GH) and pregnancy on insulin-like growth factor (IGF)-I, IGF binding protein (IGFBP)-2, and IGFBP-3 mRNA in reproductive tissues were studied in cattle. Lactating dairy cows were inseminated at estrus and treated with 25 mg/day GH (n = 8) or saline (n = 8) for 16 days. Corpus luteum (CL), ovary (CL removed), oviduct, endometrium, and myometrium were collected at the end of treatment. Messenger RNA for GH receptor, IGF-I, IGFBP-2, IGFBP-3, and actin were measured by nuclease protection assays. The CL contained more GH receptor mRNA than the other reproductive tissues examined. Expression of IGF-I mRNA was highest in myometrium, with lower amounts found in endometrium; the CL expressed the least amount of IGF-I mRNA. The IGFBP-2 mRNA was most abundant in endometrium and least abundant in CL. Expression of IGFBP-3 mRNA was detected in all reproductive tissues examined. However, endometrium, a tissue that expressed the most IGFBP-2 mRNA, had the lowest amount of IGFBP-3 mRNA. The GH receptor mRNA was decreased in cows treated with GH whereas the mRNA for IGF-I, IGFBP-2, or IGFBP-3 was not changed. In the reproductive tissues evaluated, cows that contained a conceptus at tissue collection (pregnant) had higher amounts of IGF-I mRNA than did nonpregnant cows. In summary, the level of mRNA encoding GH receptor, IGF-I, IGFBP-2, and IGFBP-3 varied within the tissues examined, suggesting that these genes may play a variety of roles in the bovine female reproductive tract. Supplemental GH failed to change the expression of IGF-I, IGFBP-2, and IGFBP-3 mRNA, possibly because of low GH receptor mRNA levels in tissues other than CL. A direct action of GH on IGF-I, IGFBP-2, or IGFBP-3 gene expression within cow reproductive tissues was not supported because the amount of IGF-I, IGFBP-2, or IGFBP-3 mRNA was not altered by GH.
Kirby
C J
CJ
Department of Animal Sciences, University of Missouri, Columbia 65211, USA.
Thatcher
W W
WW
Collier
R J
RJ
Simmen
F A
FA
Lucy
M C
MC
D000199:Actins / Q000235:genetics; D000818:Animals; D002417:Cattle / Q000502:physiology*; D005187:Fallopian Tubes / Q000378:metabolism; D005260:Female; D015870:Gene Expression / Q000187:drug effects*; D013006:Growth Hormone / Q000494:pharmacology*; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000235:genetics; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000235:genetics; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics*; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D010053:Ovary / Q000378:metabolism; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism; D011986:Receptors, Somatotropin / Q000235:genetics*; D014599:Uterus / Q000378:metabolism
D000199:Actins; D018971:Insulin-Like Growth Factor Binding Protein 2; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; D011986:Receptors, Somatotropin; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone