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S. P. COUDERT and R. V. SHORT

Summary.

Inoculation of Corynebacterium pyogenes or Vibrio foetus into the uterine lumen of ewes on the 10th day of the oestrous cycle resulted in a prolongation in the life of the corpus luteum in six out of eleven animals. In three animals, the corpora were still fully functional on Day 21 of the cycle, as judged by their progesterone concentration, as well as the progesterone concentration in ovarian vein blood.

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S. P. COUDERT and R. V. SHORT

Summary.

The treatment of hysterectomized sheep with massive doses of chlorpromazine for 6 days did not depress the secretory activity of their corpora lutea. Since chlorpromazine is likely to inhibit pituitary lh secretion and enhance prolactin secretion, these results suggest that prolactin may be luteotrophic in the ewe.

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D. W. SCHOMBERG, S. P. COUDERT and R. V. SHORT

Summary.

The steroidogenic effects of bovine luteinizing hormone (lh) and human chorionic gonadotrophin (hcg) in vivo were investigated by measuring the concentration of progesterone in peripheral plasma as an index of luteal secretory activity. The gonadotrophins were injected intravenously on Days 5, 10, 15 and 20 of the oestrous cycle, and serial samples of peripheral blood obtained before and after the injections. The steroidogenic response to lh or hcg was variable. Statistically significant increases in plasma progesterone levels were produced in five out of ten experiments; the magnitude of this increase was less than 100% in three cases and the duration of stimulation was less than 3 hr in four cases. The life-span of the corpus luteum was prolonged and new ovulations were induced by the gonadotrophins.

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S. P. COUDERT, G. D. PHILLIPS, C. FAIMAN, W. CHERNECKI and M. PALMER

Summary.

A tracer dose of the presumptive uterine luteolytic factor (PGF) was introduced into the anterior uterine vein of twelve ewes, either as a bolus or as a 40- to 60-min infusion (0·2 μCi/min). The ipsilateral ovary was left attached to or disconnected from its ligaments. Neither a bolus nor an infusion of [9-3H]PGF led to any transfer of radioactivity in the ovarian artery under controlled experimental conditions. These results show conclusively that diffusion, filtration, counter-current exchanges and active transport do not occur between the anterior uterine vein, the utero-ovarian vein and the ovarian artery. A direct and local luteolytic action of PGF is therefore questionable.

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S. P. COUDERT, G. D. PHILLIPS, C. FAIMAN, W. CHERNECKI and M. PALMER

Summary.

An experimental technique to study the local utero-ovarian circulation in fifteen ewes is described. It involves specific cannulation of the anterior uterine vein, the utero-ovarian vein and the ovarian artery. Experiments to test for direct passage between the uterine vein and ovarian artery were performed, using a highly diffusible gas (133Xe) and a large molecule radioiodinated human serum albumin (131RISA). The ovary was either left attached to or disconnected from its ligaments. Labelled RISA failed repeatedly to cross, indicating no direct shunt;133Xe crossed with an appearance time of about 20 sec, indicating passive diffusion. Anatomical casts were also prepared using coloured latex injections. Dissection failed to show any direct communications between venous and arterial vessels. These findings fail to support the concept of a local veno-arterial passage of a presumptive uterine luteolysin.