[Levels of sodium and potassium and their relation to ovarian hormones during estrus synchronization and pregnancy in ewes].

The active transport of mineral substances by cell membranes plays an important role in the neurohumoral regulation of reproductive processes in farm animals. A great importance is attributed to lipoproteins as sources of the primary precursor of steroid synthesis in the placenta and ovaries (Knopp et al., 1986; Grummer et al., 1988). The effects of hormones on K metabolism in the blood serum of ewes were studied by Hawk et al. (1961). Krajnicáková et al. (1993) observed the dynamic changes of electrolytes in the course of the reproductive cycle in ewes. Na and K levels and their relation to ovarian hormones were determined in the systemic blood stream of ewes during oestrus synchronization and pregnancy. Ten Slovak Merino ewes aged 3-5 years and weighing 40-50 kg were included in the experiment. The animals were reared conventionally. A feed ration consisted of silage, hay, feeding beet-pulp, straw and in the last two months of pregnancy it was supplemented with roughage. Water and salt were given ad libitum. Blood samples were obtained from the jugular vein prior to synchronization (day 0) and on days 3, 7 and 14 of synchronization with Agelin vaginal implants. After removing the implants the animals received 500 I.U. PMSG (Pregnant Mare Serum Gonadotropin). The animal in oestrus cycle were inseminated with fresh diluted semen. Reinsemination was not performed in this experiment. Sampling was continued on the day of insemination and on days 7, 14 and in month 2, 3, 4 and 5 of pregnancy. Na and K levels were measured by atomic absorbtion spectrophotometry using the Atom Spek device (RANG-HIGLER). Progesterone (P4) and 17 beta-oestradiol (E2) levels were assayed radioimmunologically using the respective kits (RIA-test-PROG and RIA-test-ESTRA) manufactured by URVJ Kosice. During the observation period Na levels fluctuated within 131.50 +/- 1.71 and 153.55 +/- 4.77 nmol/l of serum (Tab. I) and significantly decreased between day 14 of synchronization and the end of the investigation (P < 0.05; P < 0.01; P < 0.001). Potassium levels were observed to significantly decrease from the day of insemination on, throughout the first days of pregnancy and the above-mentioned months of gravidity, the values ranging between 4.57 +/- 0.52 and 3.93 +/- 0.36 nmol/l.(ABSTRACT TRUNCATED AT 400 WORDS)