The spectrum of lactate dehydrogenase isozymes in ovarian tissue of cows under different physiological states and pathologies

The article presents the results of studies on the lactate dehydrogenase (LDH) activity and content of its isozymes in ovarian tissue under various physiological and pathological states of cow gonads. Cow ovaries of the Ukrainian dairy black-spotted breed (age 5–8 years, live weight 450–500 kg) of different physiological states were used for research: with “early yellow body”, diameter 10–20 mm, red or brown color (EYB; n = 41); with “late yellow body”, diameter 5–15 mm, color yellow (LYB; n = 32); “follicular growth”, without corpus luteum (FG; n = 84) and with hypofunction (n = 21). The activity and content of lactate dehydrogenase (LDH) isozymes were determined in the supernatant after centrifugation of gonadal tissue homogenates prepared according to standard methods. The content of LDH isozymes (%) was determined after vertical protein electrophoresis of tissue samples in plates of 7.5 % polyacrylamide gel (PAAG) and specific staining according to J. Garbus in our modification and calculated with TotalLab TL120 software. LDH activity was determined by the rate of NADH oxidation and was calculated in µcatal/mg of protein. In all samples, 5 catalytically active enzyme bands were detected: LDH1 – LDH5. It was established that the activity and content of LDH isozymes depends on the physiological state of the gonad. Thus, in the ovarian tissue of cows, LDH activity was the same (2.8–3.0 µcatal/mg protein) under the physiological state of “follicular growth” and pathology – “hypofunction” and is lower by 0.6 and 1.0 µcatal/mg protein under conditions of “early” and “late” corpus luteum (2.0 and 2.2 µcatal/mg protein). The biggest content of LDH1 was (49.3 ± 1.64 %) in the tissue in the physiological state of “late yellow body”. The greatest amount of LDH3, LDH4 and LDH5 (16.4 ± 1.70, 11.2 ± 2.42 and 13.2 ± 3.06 %) – at state “early yellow body”. The content of LDH2 was high (27.5 ± 4.26 %) in the case of ovarian "hypofunction", and in the other physiological states, the value was lower and almost had no difference (19.8 and 22.1 %). The analysis of correlations shows the moderate dependence of LDH activity and the content of isozymes on the physiological state and hypofunction of the gonad (LDH total activity – η = 0.387, LDH 1 – η = 0.465; LDH3 – η = 0.551; LDH4 – η = 0.336; LDH5 – η = 0.347).