[Control of sex cycle functions in sheep using cloprostenol, an analog of prostaglandin F2a]. / Kontrolirane na polovotsiklichnite funktsii pri ovtsete s analoga na prostaglandin F2a-kloprostenol.

Studied was the synchronizing effect of the prostaglandin F2a analague - estrumate (ICI, England). with the Tsigai sheep. The investigations included observations on the clinical characteristics of the estrus, determination of the hormonal profile in naturally manifested estrus and in estrus induced with prostaglandin, and the conception rate with the first two successive estrus cycles along with the total conception. Estrumate was used twice ar a 9-day interval in a single dose of 125 mg, with a following programmed artificial insemination at the 48 h and the 72d hour after the second treatment. The conception rate with the first estrus of the ewes of the control and the test group was comparatively low - 41.3 and 30.4 per cent, and with the two successive cycles - 68.5 and 76.8 per cent, respectively. The total conception of the test group was 96.4 per cent as against 87.5 per cent of the control group. The studies on the content and dynamics of the basic hormones taking part in the endocrine regulation of the cycle functions in sheep with naturally manifested estrus and those with prostaglandine-unduced estrus did not show reliable differences in the hormonal profile. It was found that estrumate could successfully be used to synchronized the estrus cycle with the Tsigai sheep - a breed with pronounced conservatism' in the manifestation of cyclic functions.

[Effect of insulin on the amount of somatotropic hormone, immunoreactive insulin, blood sugar and free fatty acids in sheep]. / Vliianie na insulina vurkhu kolichestvoto na somatotorpniia khormon, imunoreaktivniia insulin, kruvnata zakhar i svobodnite mastni kiselini priovtse.

Studied was the effect of the venous injecting of insulin at the rate of 0.2 IU/kg body weight on the changes in the amount of the somatotropic hormone (STH), the immunoresponsive insulin, the free fatty acids (FFA), and the blood sugar in the serum of sheep, following their dynamics up to the 150th minute after application. The STH level rose to its peak value at the 60th min., after which it showed a lowering trend. The level of FFA dropped sharply after the injection of insulin, its lowest value being registered at the 60th min., after which it rose. By the end of the experiment the blood values of STH and FFA were close to those of the control animals. The blood sugar level started to drop 30 min. following the injection of insulin, and up to the end of the experiment a hypoglycaemic reaction was observed.

[Effect of somatotropic hormone on certain indices related to carbohydrate and fat metabolism in sheep]. / Vliianie na somatotropniia khormon vurkhu niakoi pokazateli, svurzani s vuglekhidratniia i mastniia obmen pri ovtse

Investigated was the effect of the somatotropic hormone (STH) at doses of 0.3 mg/kg and 1 mg/kg liveweight on the amount of insulin, glucose, and free fatty acids (FFA) in the serum up to the 12th hour following treatment. The activity of glucose-6-phosphatase and the amount of glycogen were studied in tissue samples taken through biopsy of the liver at the 2nd, 4th, 6th, and 8th hour after treatment with STH. The content of blood sugar decreased, and that of insulin increased in the course of one hour following treatment. The values shown by FFA first dropped (at the end of the 1st hour), and then rose by the 6th hour after treatment. The amount of glycogen and the activity of glucose-6-phosphatase increased at the 6th hour following treatment with STH. The variations shown by the investigated indices depend on the size of the STH doses.