This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Domanski, E. Articles by Stupnicka, E. Search for Related Content PubMed Articles by Domanski, E. Articles by Stupnicka, E.

Effect of prolonged infusion of small doses of LH-RH on the release of LH and ovulation in ewes during mid-anoestrus

E. Domaski, F. Przekop, B. Skubiszewski, Barbara Wróblewska and Elbieta Stupnicka

Domaski & Kochman (1968) showed that sheep were more responsive to infusion of purified hypothalamic extract into the adenohypophysis in late anoestrus than in mid-anoestrus. Natural (Schally, Redding, Matsuo & Arimura, 1972) and synthetic (Matsuo, Arimura, Nair & Schally, 1971) LH-RH have been used to induce ovulation in many species, including sheep (Reeves et al., 1972). Administration of a single intravenous injection of 150 µg synthetic LH-RH to seasonally anoestrous ewes induces LH release in all injected animals, but the LH peak is much smaller than that observed at oestrus and luteal function, assessed by peripheral progesterone levels, is absent in most animals (Crighton, Foster, Haresign & Scott, 1975). When the LH-RH was given as five injections the LH peak resembled that at natural ovulation but plasma progesterone levels were still low. Shareha, Ward & Birchall (1976) gave much smaller doses of LH-RH (25 µg/day in continuous infusions for 2 days) to anoestrous ewes but the results were again unsatisfactory.