Search Results

You are looking at 1 - 4 of 4 items for

  • Author: W. DOBROWOLSKI x
Clear All Modify Search
Free access


The removal of the persistent CL by enucleation is a widely used treatment which results, in many instances, in restoring the oestrous cycle, although a relatively high incidence of subsequent cystic changes in the ovary has also been reported (Purse & Wickersham, 1969).

Out of about 200 Fresian cows, six were selected in which the cyclic CL persisted for a period of over 30 days. The persistent CL were enucleated per rectum according to the technique of Hammond (1927). Care was taken not to let the CL slip into the ovarian bursa. For 25 days after enucleation, the ovaries were daily examined per rectum, signs of oestrus were recorded, and blood samples were collected. Plasma progesterone was determined by a proteinbinding procedure (Barcikowski & Stupnicki, 1971).

Plasma levels of progesterone before enucleation ranged from 5 to 15

Free access


Several techniques, e.g. hysterectomy, embryo transfer, insertion of an IUD into the uterus, or experimentally induced inflammation of the uterus, have shown that the uterus influences the life-span of the corpus luteum (cl) (Anderson, Bowerman & Melampy, 1963). Experiments with uterine transplantation indicate that afferent stimuli, which could cause release of gonadotrophins from the hypophysis, do not play an important rôle in this process (Melampy, Anderson & Kragt, 1964). If, in sheep, the uterus is transplanted and the ovary left in the abdomen, the cl will persist, a result indicating the close relationship between the uterus and the ovary (Goding, McCracken & Baird, 1967; McCracken & Baird, 1969). When the endometrium in rats (Bradbury, Brown & Gray, 1950), hamsters (Caldwell, Mazer & Wright, 1967) and guinea-pigs (Butcher, Chu &

Free access



The effect of gonadotrophins on the secretion rate of gonadal hormones in sheep was investigated by perfusing the ovary in situ with luteinizing hormone (lh), luteotrophic hormone (lth) and follicle stimulating hormone (fsh). The gonadotrophins were infused through the side branch of the ovarian artery and the effluent blood was collected from the utero-ovarian vein. Perfusion of the ovary on the 8th day of the oestrous cycle with lh or lth resulted in the increase of the secretion rate of progesterone within 20 to 30 min after the beginning of the perfusion; when the perfusion of the ovary was terminated the rate of progesterone secretion reverted to the original level within 20 to 30 min. Unlike lh and lth, fsh infused on the 8th day of the oestrous cycle decreased the output of progesterone. On the 15th day of oestrous cycle progesterone could not be detected in the effluent blood from the ovarian vein. At that time, perfusion of the ovaries with gonadotrophic hormones produced no effect on the secretion rate of progesterone.

Substances giving positive reaction with Barton's reagent and showing chromatographic characteristics of oestrone and oestradiol were detected in the ovarian venous blood in few animals only, and in very low concentrations. No relation was observed between the presence of these substances in the ovarian venous blood and either the phase of oestrous cycle or the type of gonadotrophin infused. Furthermore, perfusion of the ovary with fsh or lh resulted in the appearance in the ovarian venous blood of an unknown oestrogen-like substance of higher polarity than that of oestrone but lower than that of oestradiol.

Free access



Progesterone levels were determined in ovarian venous blood of nine cows with regular oestrous cycles and in three cows with prolonged maintenance of the corpus luteum. The ovarian venous blood was collected by chronic cannulation of the ovarian vein, through the anterior uterine vein. The progesterone level increased from 5·6 μg/100 ml plasma on the 1st day of the oestrous cycle to about 125 μg/100 ml on the 8th day and to about 180 μg/100 ml on Days 14 and 15 of the cycle. Thereafter, the level rapidly decreased to 10 to 20 μg/100 ml on the day of ovulation. In cows with prolonged maintenance of the corpus luteum when ovulation did not occur, the progesterone levels did not decrease and were as high as the highest luteal phase levels in cows with regular cycles. According to the data obtained, progesterone levels in ovarian blood of non-pregnant cows seem to reflect the luteal function of the ovary during the oestrous cycle.