Insulin-like growth factors in the regulation of avian ovarian functions.
In the past three decades, overwhelming evidence has accumulated to show that insulin-like growth factor (IGF)-I and -II, their receptors and binding proteins (IGFBP) (the IGF system), have major roles to play in the regulation of ovarian function in mammals. Although studies in birds did not start until 5-6 years ago, the limited information thus far available suggests that the IGFs act as autocrine/paracrine regulators of follicular growth and differentiation, just as observed in mammals. The genes for IGF-I and -II, type-I IGF receptor, IGFBP-2, and IGFBP-5 are expressed in both granulosa and theca cells of the chicken ovary. The mechanisms by which the IGF system controls ovarian function in the avian species are complex and involve interactions with the gonadotrophins (LH and FSH), growth hormone, and even other growth factors. Effects are different between strains and nutritional status.
Onagbesan
O M
OM
Laboratory for Physiology and Immunology of Domestic Animals, Catholic University of Leuven, Heverlee, Belgium. Onagbesan.OM@agr.kuleuven.ac.be
Vleugels
B
B
Buys
N
N
Bruggeman
V
V
Safi
M
M
Decuypere
E
E
D000818:Animals; D002645:Chickens / Q000502:physiology*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000502:physiology; D005786:Gene Expression Regulation; D006107:Granulosa Cells; D007265:Inhibins / Q000502:physiology; D018969:Insulin-Like Growth Factor Binding Proteins / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000502:physiology*; D007335:Insulin-Like Growth Factor II / Q000235:genetics / Q000502:physiology*; D007986:Luteinizing Hormone / Q000502:physiology; D006080:Ovarian Follicle / Q000502:physiology*; D012333:RNA, Messenger / Q000737:chemistry; D017527:Receptor, IGF Type 2 / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D013799:Theca Cells
D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; D017527:Receptor, IGF Type 2; D007265:Inhibins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone