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G. R. HOWE

Summary.

The utilization of a freezing—clearing technique with rabbit oviducts produced data which differed from those obtained by tubal flushings or autoradiography. The current study indicated that the primary site for sphincteric activity was the tubo-uterine junction rather than the ampullary—isthmic junction.

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G. R. HOWE

The fate of spermatozoa not participating in fertilization has been held to be enzymatic dissolution and phagocytic engulfment (Austin, 1957). Various investigators have observed sperm cells undergoing phagocytosis by polymorphonuclear leucocytes in the vagina and uterus (Yochem, 1929; Pitkjanen, 1960; Howe & Black, 1963). There is some evidence which indicates that ovarian hormones influence the phagocytic removal of spermatozoa from the female genital tract (Bedford, 1965; Marcus, 1966). It was the purpose of this investigation to compare the leucocytic response of the rabbit vagina, uterus and oviduct to spermatozoa under different hormonal conditions.

In the present study, rabbit semen, collected by artificial vagina techniques, was diluted in a Krebs-Henseleit-Ringer (KHR) solution to a concentration of 300 million spermatozoa/ml. The diluted semen (0·1 ml) was injected into ligated segments of the vagina

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G. R. HOWE and D. L. BLACK

Summary.

Immotile rat, rabbit, bull and human spermatozoa, alone and in combinations, were introduced into the uteri of oestrous rats. At intervals after introduction of sperm cells, the animals were killed and the contents of each oviduct were examined for the presence of spermatozoa. The utero-tubal junction did not appear to select against the passage of foreign spermatozoa nor was motility essential for transport through the junction.

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G. R. HOWE and D. L. BLACK

Summary.

Resistance to perfusion of the oviducal isthmus in anaesthetized rabbits was enhanced by adrenaline and depressed by isoprenaline. Ovariectomy significantly decreased the response of the oviducal musculature to both autonomic drugs. The degree of response of adrenergic alpha and beta receptors was primarily dependent upon oestrogen and progesterone, respectively. Increased spontaneous activity of the tubal musculature following ovariectomy appeared to be related to oestrogen withdrawal.

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G. R. HOWE and D. L. BLACK

Summary.

Motile bull spermatozoa were found in the oviducts of young calves within 13 min after vaginal insemination. Administration of pregnant mares' serum (pms) and human chorionic gonadotrophin (hcg) with or without added progesterone or a combination of progesterone and oestrogen did not affect transport.

Leucocyte invasion into the reproductive tract occurred between 4 and 8 hr after vaginal insemination. Bacteria-free semen inseminated into the vagina initiated the leucocytic response while the introduction of the diluent or sterile physiological saline solution did not result in leucocyte invasion.

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C. H. SPILMAN, G. R. HOWE and D. L. BLACK

Hawk (1967) reported that an intrauterine device (IUD) in one uterine horn blocked sperm transport, and thus fertilization, on both sides of the ovine reproductive tract. Although this effect seemed to be due to a change in uterine motility, attempts to counteract the contraceptive effect of an IUD were unsuccessful (Warren & Hawk, 1968). Furthermore, it was reported that an IUD altered uterine activity in vitro only in ovariectomized animals (Brinsfield & Hawk, 1968). Brinsfield & Hawk (1969) and Mann (1969) have observed that the direction of uterine contractions is reversed in IUD-bearing animals. The present study was undertaken to determine if an IUD caused changes in the amplitude of uterine contractions as well as a change in the direction of contractions. Preliminary data

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J. P. POLIDORO, G. R. HOWE and D. L. BLACK

Summary.

The effect of adrenergic drugs on ovum transport through the oviduct was studied at 24, 36, 48, 60, 72 and 84 hr post coitum (p.c.) in 240 mature, female Dutch-belted rabbits.

In untreated rabbits, ova were located in the area of the ampullaryisthmic junction at 24 hr p.c.; most ova entered the uterus between 72 and 84 hr p.c. Epinephrine increased (P<0·01) the rate of ovum transport at 60 and 72 hr p.c., and most of the ova were found in the uterus. Phenoxybenzamine (α-blocker) inhibited ovum transport at 48 hr p.c. (P<0·05), while propranolol (β-blocker) was ineffective in altering ovum transport in any of the time periods.

Regulation of ovum transport through the rabbit oviduct appeared to be governed in part, by a neural-endocrine interrelationship; this relationship could be altered by adrenergic stimulants and blocking agents.

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D. CARLSON, D. L. BLACK and G. R. HOWE

Little is known regarding the physiological rôle of oviduct fluid on ova and spermatozoa in the reproductive tract. VanDemark (1958) and Bishop (1961) suggested that luminal fluids may be an important transport and nutrient medium for the gametes; others felt that oviduct secretions influenced sperm activity (Olds & VanDemark, 1957a) or aided the capacitation process (Austin, 1951 : Chang, 1951). Oviduct fluid has been collected from several species by ligation of portions of the genital tract (Blandau, Jensen & Rumery, 1958), flushing portions of the tract (Heap, 1962), expressing the contents of tracts after slaughter (Olds & VanDemark, 1957b), and cannulation of portions of the tract in living animals (Clewe & Mastroianni, 1960; Restall, 1966). To our knowledge, oviduct secretion has never been continuously collected throughout the oestrous cycle and an attempt was made to determine whether the volume, protein content, or glucose content of oviduct fluid varied during the oestrous cycle. Cows of small size