Semen-induced luteal phase and identification of a LH surge in the koala (Phascolarctos cinereus)
- 1 November 2004
- journal article
- Published by Bioscientifica in Reproduction
- Vol. 128 (5), 629-634
- https://doi.org/10.1530/rep.1.00300
Abstract
The koala ovulates in response to mating. The purpose of this study was to document the LH surge induced by copulation and to investigate the potential roles of mechanical stimulation of the urogenital sinus and deposition of semen in induction of the luteal phase. In experiment 1, serial blood samples from four koalas that underwent normal mating showed elevated concentrations of LH approximately 24–32 h post-coitus. There was no corresponding elevation in LH in koalas (n = 4) that were exposed to the presence of a male but received no physical contact. In experiment 2, koalas on day 2 of oestrus were exposed to one of the following treatments (n = 9 per group): artificial insemination with 1 ml 0.9% sterile saline (control group), insemination with 1 ml koala semen, stimulation of the urogenital sinus with a purposebuilt glass rod (designed to mimic the action of the penis during natural mating) and urogenital stimulation with the glass rod followed by insemination of 1 ml koala semen. Confirmation of a luteal phase was based on evidence of a prolonged return to oestrus, parturition and/or elevated progesterone concentrations. Insemination of saline (0/9) and urogenital stimulation (0/9) failed to induce a luteal phase. Insemination of semen without glass rod stimulation resulted in a luteal phase in 4/9 koalas, three of which gave birth. Insemination of semen in combination with urogenital stimulation produced a luteal phase in 7/9 koalas, four of which gave birth. Semen had a significant effect on induction of the koala luteal phase (P < 0.001) but glass rod stimulation had no such effect (P = 0.335). It was concluded that semen must be involved in the induction of a luteal phase in the koala. The results presented in this study will serve to improve optimal timing and induction of ovulation for artificial insemination in the koala.Keywords
This publication has 18 references indexed in Scilit:
- Seasonal changes in the reproductive organs and plasma and pituitary hormone content of the male Bennett's wallaby (Macropus rufogriseus vufogriseus)Journal of Zoology, 1991
- Reproduction in the female dromedary (Camelus dromedarius): A reviewAnimal Reproduction Science, 1987
- Effects of removal in late pregnancy of the corpus luteum, Graafian follicle or ovaries on plasma progesterone, oestradiol, LH, parturition and post-partum oestrus in the tammar wallaby, Macropus eugeniiReproduction, 1985
- Coital Stimuli Controlling Luteinizing Hormone Secretion and Ovulation in the Female Ferret1Biology of Reproduction, 1985
- Identification of the major steroids in ovarian and adrenal venous plasma of the brush-tail possum (Trichosurus vulpecula) and changes in the peripheral plasma levels of oestradiol and progesterone during the reproductive cycleJournal of Endocrinology, 1985
- Testicular GnRH-like factors: Characterization of biologic activityBiochemical and Biophysical Research Communications, 1984
- Reflex LH Release in Estrous Cats Following Single and Multiple CopulationsBiology of Reproduction, 1980
- Ovarian Regulation of Postcoital Gonadotropin Release in the Rabbit: Reexamination of a Functional Role for 20 αDihydroprogesterone1Endocrinology, 1976
- THE EFFECT OF MATING UPON LH RELEASE IN MALE AND FEMALE VOLES OF THE SPECIES MICROTUS AGRESTISReproduction, 1975
- Time-Courses of LH and FSH Release After Mating in the Female RabbitEndocrinology, 1973