Insulin resistance: the link between metabolic disorders and cystic ovarian disease in high yielding dairy cows?

A preliminary investigation was performed to examine whether insulin resist ance is a factor in the pathogenesis of cystic ovarian disease (COD) in hig h-yielding dairy cows. Tn total 30 cows, of which 15 were diagnosed as suff ering from COB based on the anamnesis and clinical examination. and the oth er 15 served as matched controls, were subjected to an intravenous glucose tolerance test (IVG1TT). The aim of the study was to investigate whether in sulin activity was altered in COD cows. Differences in glucose clearance be tween the COD cows and their controls were analyzed comparing the fractiona l turnover rate (k), the glucose half-time (T-1/2), and the area under the curve (AUC) 60 and 120 min after infusion. Differences in insulin response were analyzed comparing the insulin increment, the insulin peak concentrati on, and the AUC 60 and 120 min after glucose infusion. Although insulin res istance, attended by a secondary hyperinsulinemia, is stated to directly co ntribute to the ovarian abnormalities that characterize the polycystic ovar y syndrome (PCOS) in human medicine, this was not observed in COD cows. On the contrary, COD cows appeared to have a low insulin response following an intravenous glucose load as compared with their matched controls. This was illustrated by significantly lower insulin increments (P = 0.04) and lower insulin peak concentrations (P = 0.04). As COD cows had a significantly lo wer insulin response to a standard glucose load, it was concluded that insu lin could be a factor in the pathogenesis of COD in dairy cows. (C) 1999 El sevier Science B.V. All rights reserved.