Effect of negative energy balance on the insulin-like growth factor system in pre-recruitment ovarian follicles of post partum dairy cows

• DOI: 10.1530/rep-06-0122
• Publication Date: 2007-03-22T13:51:21Z
• Authors: S Llewellyn; R Fitzpatrick; D A Kenny; J J Murphy; R J Scaramuzzi; D C Wathes
• Keywords: 2. Zero hunger; Granulosa Cells; Postpartum Period; Gene Expression; Receptor, IGF Type 1; Insulin-Like Growth Factor Binding Protein 1; Insulin-Like Growth Factor Binding Protein 2; 03 medical and health sciences; Insulin-Like Growth Factor Binding Protein 3; 0302 clinical medicine; Follicular Phase; Insulin-Like Growth Factor Binding Protein 4; Ovarian Follicle; Insulin-Like Growth Factor II; Somatomedins; Animals; Cattle; Female; RNA, Messenger; Insulin-Like Growth Factor I; Insulin-Like Growth Factor Binding Protein 5; Insulin-Like Growth Factor Binding Protein 6; In Situ Hybridization

Post partum negative energy balance (NEB) in dairy cattle is associated with a delayed return to ovarian cyclicity and reduced fertility. This study compared the IGF system of pre-recruitment follicles between cows mild ( n = 6) or severe NEB during early lactation. Ovaries were collected second week post , when circulating concentrations IGF-I glucose lower P < 0.01) cows. mRNA expression for IGF-II, type 1 receptor (IGF-1R) IGF-binding proteins (IGFBP)-1 IGFBP-6 was determined by situ hybridisation individual using radiolabelled oligonucleotide probes. Follicles classified as very small (1–2.5 mm) (2.5–5 healthy atretic. Relative measured optical density (OD) units image analysis. Thecal IGF-II highest small, 0.05). Granulosa cell IGFBP-2 only component change EB status, higher IGFBP-1 IGFBP-3 undetectable. IGF-1R, IGFBP-4 IGFBP-5 not significantly altered follicle size health, but tended increase atretic follicles. The pattern theca paralleled that mRNA, 0.05) levels healthy, In conclusion, may alter bioavailability locally produced modulate stages required maintain normal cyclicity.