Early Pregnancy in the Pig

Perry, J. S.; Rowlands, I. W.

doi:10.1530/jrf.0.0040175

Cited by 202 publications

(89 citation statements)

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“…In addition, they have noted that the contribution of the corpora lutea of metestrous ovary to the total synthesis of progesterone and 20a-OH-P is much greater than that of the remaining tissue but the responses of ovarian progestins synthesis to LH are not superior at this stage in comparison with that in the other stages of the cycle. A self-sustaining property of the corpus luteum and its autonomic secretion of progesterone have also been demonstrated in sheep and guinea pigs (Short, 1964;Perry and Rowlands, 1962). In this connection, the highest level of progesterone content in the ovarian tissue obtained in the early diestrous afternoon may be the reflection of the maximal development of the corpora lutea at this time, and a gradual decrease of progesterone content accompanied with the gradual increase of 20a-OH-P content in the ovary towards the estrous stage is supposed to reflect the aging of the corpora lutea, in which a correlative increase of 20a -hydroxysteroid dehydrogenase takes place (Balogh, 1964;Pupkin et al, 1966 …”

Section: Discussionmentioning

confidence: 97%

Ovarian Secretion of Progesterone and 20α-Hydroxypregn-4-en-3-one during Rat Estrous Cycle in Chronological Relation to Pituitary Release of Luteinizing Hormone

1969

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Section: Discussionmentioning

confidence: 97%

Ovarian Secretion of Progesterone and 20α-Hydroxypregn-4-en-3-one during Rat Estrous Cycle in Chronological Relation to Pituitary Release of Luteinizing Hormone

1969

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“…Since no examinations were conducted earlier in pregnancy the embryonic loss may have been even higher because total litter loss could not be determined (see Perry & Rowlands, 1962 …”

mentioning

confidence: 99%

The fertilizing capacity of epididymal spermatozoa in the pig

Holtz¹,

Smidt²

1976

Reproduction

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In all mammals studied so far, with the possible exception of man, it has been shown that sperm cells emerging from the testis have to pass through at least part of the epididymis before they acquire the ability to fertilize (Bedford, Calvin & Cooper, 1973;Bedford, 1974).The literature regarding the fertilizing capacity of spermatozoa collected from different segments of the epididymis in laboratory animals has been summarized by Paufler & Foote (1968) and Orgebi n\x=req-\ Crist (1969). Little information is available for the large domestic species although bulls have been successfully inseminated with spermatozoa from the cauda epididymidis (Lardy & Ghosh, 1952;Barker, 1954;Igboeli & Foote, 1968).The present experiments were therefore conducted to examine the fertilizing capacity of spermatozoa from different regions of the epididymis in the domestic pig.Text- fig. 1. Diagram showing the segments into which the boar epididymis was divided.Epididymides were obtained by castrating sexually rested 7-24-month-old German Landrace boars under sodium pentobarbital anaesthesia. Each epididymis was divided into segments (Text- fig. 1). Initially, the segments were the caput, corpus, proximal and distal cauda epididymidis. In subsequent experiments the distal 1 cm of the corpus (Corpus 2), the most proximal (Cauda 1), and the terminal (Cauda 4) portion of the cauda were studied. Each segment was placed in a fine-meshed plastic sieve, submerged in physiological saline at room temperature, and minced gently but thoroughly with fine scissors to provide a suspension of largely intact spermatozoa almost free of contamination with blood or other tissue. Suspensions from similar epididymal segments of several boars were pooled to eliminate individual boar effects.Sperm density was determined by counting two representative samples taken from each suspen¬ sion. After diluting the samples 5-10 times depending on sperm density, haemocytometers were filled and placed in a moist atmosphere for 5 min before counting commenced. Insemination doses of 120 ml, each containing a minimum of 5 IO9 spermatozoa, were prepared by adding saline. Process¬ ing time in the laboratory was about 2 hr and the time between castration and insemination was 4-6 hr.For the inseminations, prepubertal Landrace gilts weighing about 75-85 kg were given a single i.m. injection of a combination of 400 i.u. PMSG and 200 i.u. HCG (PG 600: Intervet International), and inseminated without regard to oestrous symptoms on Days 4 and 5 after the injection. The animals were killed 3-4 weeks after insemination and the ovaries and uterine contents inspected.Of the 141 gilts treated, 119 (84%) responded to the gonadotrophin treatment with 5 or more ovulations, as judged by counts of CL, and were included in the experiment.

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“…In the pig, eggs are fertilized in the ampullary portion of the oviduct, and the embryos then enter the uterus in the 4-to 8-celled stage of development about 48 hr after ovulation (Perry & Rowlands, 1962). Intrauterine migration and spacing of the embryos occur between Days 4 and 12, whereas embryo-endometrial attachment proceeds at Days 11-13, and implantation progresses between Days 12 and 18 (Short, 1969;Anderson, 1974).…”

Section: Discussionmentioning

confidence: 99%