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C J Pauerstein

Publications and source records attributed to C J Pauerstein.

At least 73 records · Page 4Linked to original sources
PubMed1976

Temporal relationships critical to estrogen-induced delay of ovum transport.

Previous studies have shown that a pharmacologic dose of estradiol given at the time of injection of human chorionic gonadotropin (HCG) significantly delays the transport of ova through the rabbit oviduct and that the site of delay is located at the ampullary-isthmic junction. The current experiments investigated the effects of varying the timing of the estrogen injection on ovum transport rates. Fifty-eight rabbits received injections of either Depot-estradiol or crystalline estradiol at various times before or after the injection of HCG. "Tube-locking" resulted when estrogen was administered before or at the time of HCG administration, whereas acceleration occurred when estrogen was given 12 to 24 hours after HCG. The results demonstrate that pharmacologic doses of estrogen exert two effects on ovum transport in the rabbit: (1) delay at the ampullary-isthmic junction and (2) acceleration once that junction has been traversed. The possible application of these results to contraception is discussed.

Animals↗
PubMed1976

The hormonal control of the guinea pig corpus luteum during early pregnancy.

Forty guinea pigs were divided into two groups, pregnant and nonpregnant, and were operated upon on days 10, 12, 14, and 16 of the ovarian cycle or of pregnancy. Blood was obtained from the utero-ovarian vein, and prostaglandin F2alpha (PGF2alpha), prostaglandin E (PGE), progesterone, and estrogen content was assayed by radioimmunoassay. Increased levels of PGF2alpha preceded a drop in progesterone levels in nonpregnant animals, reflecting luteolysis. In pregnant animals, the level of PGF2alpha remained low, and progesterone levels increased. PGE levels were similar in the two groups. These results suggest that the low PGF2alpha levels seen during early pregnancy are related to corpus luteum rescue.

Animals↗
PubMed1976

Pattern and duration of ovum transport in the baboon (Papio anubis).

The normal pattern and duration of ovum transport was determined in a group of unmated, spontaneously ovulating baboons (Papio anubis) in which the time of ovulation had been determined directly using serial laparoscopy or indirectly using periovulatory estrogen values, perineal sex skin changes, and corpus luteum histology. At laparotomy, the reproductive tract was segmentally flushed at 24, 48, or 72 hours after ovulation and the position of the ova within the tract ascertained. Ova were consistently recovered from the ampulla 24 hours after ovulation, from both the ampulla and isthmus at 48 hours, and from the uterus 72 hours after ovulation. These results suggest that the baboon constitutes a potentially valuable animal model for the investigation and preclinical evaluation of contraceptive technics affecting tubal function.

Animals↗
PubMed1976

Effect of particle size on time course of transport of surrogate ova through the rabbit oviduct.

The time-course of transport of plastic microspheres of 100, 200, 400, 800, and 1000 mu diameter through the rabbit oviduct was studied under various hormonal conditions. During estrus, the rabbit oviduct rapidly transports particles of 200 mu diameter to the uterus. After ovulation, the passage of these particles is delayed, first at the ampullary-isthmic junction, and then along the isthmus, perhaps influenced by a second site of resistance at the uterotubal junction. Particles of 100 mu diameter are not subject to these delays but pass rapidly to the uterus. Our data support the idea that the rapid passage of 100-mu spheres reflects a size-related inability of the resisting "gates" to limit their passage. Pharmacologic doses of estrogen act to prolong or increase the resistance to particle passage at the ampullary-isthmic junction and apparently also accelerate transport through the isthmus. Progesterone presumably increases the efficiency of the "gate" at the ampullary-isthmic junction, hastens transport through the isthmus, and seems to "open the gate" at the utero-tubal junction. Further experiments are required to prove or negate these inferences.

Acceleration↗
PubMed1975

Use of radioactive microspheres for studies of tubal ovum transport.

Experiments were designed to ascertain the fidelity with which radioactive plastic ovum models imitated the time-course of transport of natural ova through the rabbit oviduct. After location of the radioactive microspheres within the intact oviducts, the genital tracts were removed and cleared in benzyl benzoate. Natural ova and ovum surrogates were then visualized in situ. The radioactive microspheres were reasonably good models of transport of natural ova and their sojourn in the oviduct was shortened by progesterone and prolonged by estrogen. Thus they should be useful tools for future studies of own transport under various conditions.

Animals↗
PubMed1975

Effect of progesterone on estrogen receptors in the rabbit uterus.

The macromolecular binding of estradiol was investigated in the rabbit uterus under various hormonal states in a search for evidence of progesterone antagonism of the estrogen-receptor complex interaction. Progesterone did not alter the sucrose gradient sedimentation characteristics of the estrogen-receptor complex in estrus or castrate animals. Progesterone treatment of castrated animals did not alter the absolute number of EBS (estrogen-binding sites) per cell, but did result in decreased relative concentration of EBS by increasing the soluble protein content of the cells over that seen in untreated castrates. Castration did not alter the absolute number of EBS per cell but did increase the relative concentration of estrogen binding in the cytosol.

Animals↗
PubMed1975

Clinical implications of oviductal physiology and biochemistry.

Current investigations of the oviduct including methods for studying oviductal physiology, electrophysiology, contractility, roles of the autonomic nervous system and prostaglandins on oviductal motility and egg transport are summarized in this article. In addition, current knowledge of the transport and survival of sperm, egg transport, capacitation, ovum maturation, fertilization, and preimplantation development in the oviduct and the biochemistry and physiology of oviductal secretions are reviewed. An attempt is made to place these investigations in clinical context and to identify promising area for future investigations pertinent to human reproduction.

Animals↗
PubMed1975

Temporal relationships critical to progesterone-induced acceleration of ovum transport.

Previous investigators have demonstrated that 2.5 mg fo progesterone, administered intramuscularly to rabbits on the day of ovulation and the 2 preceding days (Days -2, -1, and 0) significantly and consistently accelerates ovum transport. In contrast, when given on the day of ovulation and the 2 following days (Days 0, +1, and +2), progesterone does not accelerate ovum transport. The experiments reported were designed to define more precisely the temporal relationships critical to progesterone-induced acceleration of tubal ovum transport. Our observations suggest 3 important conclusions: 1) Progesterone, when given at least 1 day, and not more than 2 days, prior to ovulation does induce accelerated ovum transport. 2) The progesterone responsive mechanism is dose dependent. 3) The acceleration is partially antagonized if progesterone treatment is begun 3 days prior to ovulation.

Animals↗
PubMed1975

Effects of hormonal treatments which alter ovum transport on beta-adrenoceptors of the rabbit oviduct.

Beta-Adrenoceptor activity of rabbit oviductal isthmus has been determined quantitatively in vitro in tissues isolated 24 and 72 hours after human chorionic gonadotropin injection and after two hormonal treatments known to accelerate (progesterone) and retard (estrogen) ovum transport. Under conditions in which ova are located at the ampullary-isthmic junction and distal isthmus, the isthmus demonstrates a low incidence of spontaneous activity in vitro, poor response to acetylcholine, low affinity of beta-adrenoceptors for isoproterenol, and low efficacy of isoproterenol to inhibit acetylcholine-induced contractions. Under conditions in which ova are passing into the uterus, the isthmus shows the converse of these parameters. These data support the hypotheses that the oviductal isthmus functions as an adrenergic sphincter and that the actions of progesterone and estrogen in altering ovum transport rates are at least partially mediated through changes in adrenoceptors.

Acetylcholine↗
PubMed1975

Effect of prostaglandin E2 on oviductal adenosine 3':5'-monophosphate levels during estrus and pseudopregnancy.

The basal levels of adenosine 3':5'-monophosphate (cyclic AMP) in the oviductal isthmus were lower during pseudopregnancy than during estrus. No differences were observed in the ampulla. Prostaglandin E2(PGE2) significantly increased cyclic AMP levels in the isthmus during pseudopregnancy but not during estrus. In contrast, in the ampulla, PGE2 did not alter cyclic AMP levels in either hormonal condition. Theophylline increased cyclic AMP levels in the isthmus and in the ampulla during pseudopregnancy. These results show that PGE2 causes a specific increase in cyclic AMP levels in the isthmus after ovulation.

Adenosine Monophosphate↗