Antitumor activity of streptococcal acid glycoprotein produced by Streptococcus pyogenes Su

Streptococcal acid glycoprotein (SAGP) was purified from the cultured cells of Streptococcus pyogenes Su, and its in vitro and in vivo antitumor activities were investigated in comparison with those of OK-432, a cell preparation of S. pyogenes Su which is used clinically as a potent antitumor agent. SAGP inhibited the growth of several tumor cell lines in vitro at less than 0.1 microgram/ml, while it did not affect the growth of the other tumor and normal cell lines even at 10 micrograms/ml. This selective cytotoxicity is a unique characteristic of SAGP. OK-432 did not show cytotoxicity in vitro. SAGP also showed a considerable life-span-prolonging effect on mice bearing Meth A tumor and inhibited the growth of sarcoma 180 tumor implanted im. The comparison of antitumor activities between SAGP and OK-432 definitely suggested a difference in the mechanisms of their actions, even though they were derived from the same bacterial strain.

Changes in the secretion of inhibin and steroid hormones during induced follicular atresia after hypophysectomy in the rat

Sequential changes in the function of antral follicles during the period of follicular atresia were investigated after hypophysectomy (Hypox) at 1100 hr on proestrus. Within 6 hours after Hypox, concentrations of progesterone (P), testosterone (T) and estradiol-17 beta (E) decreased abruptly in ovarian venous plasma (OVP) and follicles showed a reduced ability to ovulate. Six hours after Hypox, ovulation was still induced by human chorionic gonadotropin (hCG) in all animals but with significantly fewer number of oocytes compared to the group given hCG at 1100 hr on the day of proestrus. Nine hours after Hypox, several granulosa cells of all large follicles (greater than 400 microns in diameter) exhibited morphological signs of atresia. Twelve hours after Hypox, all large and medium sized (200-400 microns in diameter) follicles showed advanced stages of atresia and almost all follicles failed to ovulate in response to hCG. Inhibin activity in OVP declined more slowly compared to the profiles of steroid hormones and 53% of the initial inhibin activity was still maintained at 18 hours after the operation. Inhibin activity further decreased to 7% of the initial level at 24 hours and was undetectable by 48 hours after Hypox. These results suggest that fully developed Graafian follicles gradually lose their ability to secrete inhibin in contrast to the rapid decrease in secretion of steroid hormone during the process of atresia.

Mode of action of chlorpromazine (CPZ) blockage on 13,14-dihydroprostaglandin F2-alpha formation in rat ovary

The mode of action of the inhibitory effect of CPZ on 13,14-dihydroprostaglandin F2-alpha (13,14H2-PGF2-alpha) formation in rat ovary was examined. The inhibition of 13,14H2-PGF2-alpha formation and of ovulation induced by a proestrus were completely recovered by an injection of hCG (25 IU/rat) or LH-RH (500 ng/rat) at 15:00 on the same day. 13,14H2-PGF2-alpha formation and ovulation were not inhibited by a single injection of prolactin (PRL:6 IU/rat) at 13:00 on the day of proestrus. Repeated injection of PRL inhibited cyclic ovulation and 13,14H2-PGF2-alpha formation. The estrus cycle of PRL treated animals showed a continuous state of diestrus. Although 13,14H2-PGF2-alpha formation and ovulation were inhibited by the repeated injection of CPZ, the repeated-simultaneous injection of CPZ and bromocriptine at 10:00 once a day for 3 days from the first day of diestrus partly restored both and entirely reversed the suppression of the cyclic-changes in the in the vaginal smear pattern. These results indicate that the inhibition of 13,14H2-PGF2-alpha formation induced by a single injection of CPZ probably occurs via the suppression of LH-RH release from the hypothalamus, whereas PRL secretion may participate in the inhibitory effects of repeated injections of CPZ.

Tenascin is a stromal marker for epithelial malignancy in the mammary gland

Tenascin is an extracellular matrix glycoprotein that is not present in the normal mature rat mammary gland. The distribution of tenascin was examined by immunohistochemistry in mammary tumors from carcinogen-treated and untreated rats, in virus-induced mammary tumors from mice, and in a variety of mammary gland lesions from humans. Tenascin was detectable in the stroma of the malignant but not of the benign tumors from all species. An inhibition ELISA, testing homogenates of rat tumors, confirmed that tenascin was present in malignant but not in benign tumors. Thus, tenascin was consistently found to be a stromal marker for epithelial malignancy in the mammary gland. It is concluded that tenascin may be involved in the interactions between the epithelial and mesenchyme-derived (stromal) components of the mammary gland, which are known to influence epithelial carcinogenesis in this organ.

Difference in the response of follicular maturation and ovulation between early and late lactating rats after removal of the litter

The mechanisms responsible for the 24-h difference in the time of the next ovulation after litter removal between early and late lactating rats were investigated. At 11.00 h on day 5 of lactation, concentrations of oestradiol-17 beta and inhibin activity in ovarian venous plasma were lower than those on day 17, corresponding to the absence of healthy Graafian follicles. After removal of the litter on day 5 of lactation a small surge of FSH with a steady increase in basal levels of LH occurred to initiate follicular maturation, and ovulation occurred 4 days later. After removal of the litter on day 17 of lactation a surge of FSH was not observed, due to high levels of inhibin activity in ovarian venous plasma, until the time of preovulatory surges of gonadotropin which occurred 2 days later and resulted in ovulation the next morning. Prolactin concentrations decreased similarly in both groups abruptly after removal of the litter. A decrease in plasma concentrations of progesterone occurred 42 h after removal of the litter on day 5, though it occurred 18 h after removal of the litter on day 17. These results indicate that the 24-h delay of ovulation after litter removal on day 5 of lactation, as compared with the time of ovulation after litter removal on day 17, is due probably to the absence of healthy antral follicles and high activity of corpora lutea secreting progesterone at the time of litter removal.

[Scintigraphic imaging of autotransplanted splenic grafts by 99mTc-labeled heat-damaged erythrocytes]

Splenectomy is known to increase the risk of bacterial infection. Recently splenic autotransplantation has been suggested as a method of preserving splenic function. In order to demonstrate the viability of transplanted tissue, spleen scintigraphy using 99mTc labeled heat damaged erythrocytes were carried out. So far 21 studies have done in 12 patients. Spleen scans were positive 1 month after surgery, though images showed poor contrast against considerable background of bone marrow and blood pool. The quality of the images much improved five to twelve months after surgery. Functioning splenic autografts could be also shown by scintigraphy using 99mTc sulfur colloid, but the image quality was poorer, particularly within the early stage after operation. Labeling yields were 79.8% on the average, ranging from 45.6-92.3%, that affected little the quality of images. Important techniques in the splenic autotransplantation imaging include a thorough elimination of free 99mTcO4- before injection and to use comparatively small volume of damaged erythrocytes.

Initiation of ovarian follicular maturation without a surge of FSH in cyclic rats treated with antiserum to LH-releasing hormone

The relationship between a surge of FSH and the initiation of follicular maturation was examined using rats with a 4-day oestrous cycle. When antiserum against LH-releasing hormone (LHRH-AS) was given at 13.00 h on the day of pro-oestrus (day 0), surges of FSH and LH were blocked. Plasma FSH and LH were maintained at low basal levels without a surge release until the next spontaneous surge occurred on the afternoon of day 4, the predicted day of pro-oestrus. Follicular responsiveness to an injection of human chorionic gonadotrophin (hCG) indicated that preovulatory follicles, present at the time of treatment with LHRH-AS, were capable of ovulating on day 1 but had regressed by day 2. Subsequently, as shown by the ovulatory response to hCG, a new set of follicles had begun to mature by the morning of day 3 without a preceding surge of FSH. Changes in oestradiol-17 beta levels in the plasma throughout the oestrous cycle were the same in rats injected with LHRH-AS or non-immune control serum. The mature follicles in the rats treated with LHRH-AS thus retained the capacity to ovulate after losing their ability to secrete oestrogen. These results suggest that an FSH surge is not essential for initiation of follicular maturation and that basal levels of FSH may be enough to initiate follicular maturation in the absence of newly formed corpora lutea.

Inhibin activity and secretion of gonadotropin during the period of follicular maturation

To evaluate the relative contributions of the ovarian inhibin and estradiol-17 beta (E) on the regulation of FSH secretion, inhibin and E in ovarian venous plasma (OVP) and FSH and LH in peripheral plasma were simultaneously measured using superovulating rats with special reference to follicular maturation. By the transplantation of a pituitary gland from adult male rats under the kidney capsule between 1100 and 1200 hr on diestrus-1 in cyclic rats, superovulation was successfully induced on the morning of the next estrus without any additional treatment with human chorionic gonadotropin (hCG). The number of maturing follicles capable of ovulating in response to hCG significantly increased at 12 hours after the grafting as compared with sham-operated controls and further increases occurred until the afternoon of proestrus. In the superovulating rat, first and second surges of FSH were completely blocked and an LH surge was also partially suppressed during the periovulatory period when surges of FSH and LH were normally observed in controls. Contents of FSH as well as LH in the animal's own pituitary gland were suppressed significantly after the grafting as compared with controls. A marked increase in inhibin activity in OVP of rats with a pituitary transplant occurred concomitantly with an increase in the number of follicles capable of ovulating whereas E levels in OVP did not so. Inhibin activity in OVP at each point was much higher in the pituitary grafted rats than in controls but this was not true for E levels. These results suggest that ovarian inhibin derived from the maturing follicles rather than E may be a primary factor for regulation of FSH secretion, and high levels of endogenous inhibin can suppress synthesis of LH as well as FSH in the pituitary gland of the female rat.

Induction of selective release of FSH in castrated male rats bearing an ovarian transplant by the administration of human chorionic gonadotrophin

The present study was undertaken to determine whether hypothalamic differentiation is involved in the selective release of FSH during the periovulatory period using adult male rats castrated and implanted with an ovary. Adult male rats (70-90 days old) were castrated and an ovary obtained from a prepubertal female rat (26 days old) was immediately grafted subcutaneously. Four weeks later, human chorionic gonadotrophin (hCG, 10 i.u.) was injected i.v. into the experimentally manipulated rats to induce ovulatory changes in the grafted ovaries. Another group of similarly prepared rats was injected with 0.9% (w/v) NaCl solution as controls. After injection of hCG, plasma concentrations of FSH increased significantly by 6 h, reached peak values at 12 h and declined to control levels at 36 h. On the other hand, plasma concentrations of LH were reduced by 6 h and decreased further during the next 36 h. An abrupt fall in plasma concentrations of oestradiol-17 beta occurred within 3 h of the administration of hCG. Histological examination revealed that ovulatory changes and luteinization of follicles were induced in grafted ovaries by 18 h after the injection of hCG. Thirty-six hours after treatment with hCG, a set of newly formed corpora lutea was observed in grafted ovaries and plasma concentrations of progesterone were raised. Treatment with oestradiol-17 beta did not inhibit the selective release of FSH after the administration of hCG, suggesting that the abrupt decrease in secretion of oestradiol-17 beta from the grafted ovary is not involved in the occurrence of the FSH surge.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between characteristics of immunoreactive LH/FSH cells and the levels of gonadotropin in the female rat

Morphological and functional changes of pituitary LH/FSH cells in the female rat were investigated using the parameters on the radioimmunoassay, immunohistochemistry and ultrastructure. Changes in immunostainability, populations of intensely immunostained LH and FSH cells and total volume of secretory granules were correlated with the changes in pituitary LH and FSH contents during the estrous cycle. The immunohistochemical feature of gonadotropin release is the transformation of intensely immunostained gonadotrophs into the weakly stained ones. Secretory granules of small diameter (less than 150 nm) were numerous just before LH and FSH surges then sharply declined along with LH and FSH surges. The number of secretory granules of large diameter (larger than 150 nm) also decreased when LH and FSH surges took place. Then the number increased progressively until 17.00 h on the day of diestrus, corresponding to the increase in pituitary LH and FSH contents. It is suggested that small secretory granules are a release pool while large ones are a reserve pool.

Inhibin activity in ovarian venous plasma during pregnancy, pseudopregnancy and lactation in the rat

Inhibin activity in ovarian venous plasma and concentrations of FSH and LH in peripheral plasma were examined in rats during pregnancy, pseudo-pregnancy and lactation and correlated with the status of the ovarian follicular population. Inhibin activity was assessed in terms of its ability to suppress the 48 h secretion of FSH in a dispersed anterior pituitary cell culture system. FSH and LH were measured by radioimmunoassay. Inhibin activity in ovarian venous plasma was always detected when Graafian follicles were present, such as Days 3, 5 and 10 of pseudopregnancy, Days 5, 10, 20 and 21 of pregnancy, Days 3, 5 and 10 of lactation in mothers with 2 pups and Days 0, 10, 15 and 20 of lactation in mothers with 8 pups. Inhibin activity in ovarian venous plasma was undetectable whenever healthy antral follicles were absent, such as Days 15 of pregnancy and Days 2, 3, 4 and 5 in lactating rats with 8 pups. No FSH surge occurred during these periods of low inhibin activity in ovarian venous plasma, in striking contrast to normal cyclic rats. These results indicate that inhibin activity in ovarian venous plasma of rats varies with the number of healthy antral follicles during the luteal phase. Ovarian inhibin in conjunction with other factors such as steroid hormones or the suckling stimulus may be involved in the regulation of FSH secretion in the luteal phase of the rat.

Induction of superovulation in prepubertal female rats by anterior pituitary transplants

Transplants of 26-day-old rats of an anterior pituitary gland from adult intact or castrated male, 20-day-old or adult ovariectomized female donors (all of which contained large amounts of FSH) resulted in superovulation in recipients on the morning of Day 29. Transplants of the gland from 20-day-old males and adult cyclic females could not advance the time of first ovulation or induce superovulation. In the rats in which superovulation could be induced, a marked increase in plasma FSH was noted in recipients shortly after transplantation and the high levels of plasma FSH were maintained until at least 12 h after grafting. These rats also showed preovulatory surges of LH and FSH 54 h after grafting. No obvious elevation of plasma FSH was noted over 72 h in recipients in which superovulation could not be induced. These findings suggest that the final maturation of follicles for superovulation is induced by a transient release of a large amount of FSH from the grafted pituitary gland and that the sex of the pituitary donor has no bearing on this phenomenon.

An inverse relationship between inhibin and follicle-stimulating hormone during the period of ovulation induced by human chorionic gonadotrophin in dioestrous rats

To investigate the mechanism of the selective surge of FSH during the period of ovulation induced by human chorionic gonadotrophin (hCG) in dioestrous rats, inhibin activity in ovarian vein plasma was determined at varying time-intervals after treatment with hCG using the primary monolayer culture system of anterior pituitary cells. Inhibin activity in ovarian vein plasma had already decreased 6 h after injection of hCG, when concentrations of FSH in the plasma were still low in three of four animals. Inhibin activity further decreased 12-18 h after hCG, when a selective surge of FSH occurred. Inhibin activity increased to the level before hCG treatment 24 h after the treatment, when ovulation was completed and the FSH surge terminated. These results suggest that the selective surge of FSH occurs as a consequence of the decrease in inhibin secretion from the ovary, which is perhaps due to the ovulation dose of hCG altering the functional activity of the granulosa cells in the large Graafian follicles.

Mechanisms of suppression of ovarian follicular development during lactation in the rat

To determine the mechanisms responsible for the suppression of follicular development in the lactating rat, in vivo and in vitro determinations of steroid and peptide hormones combined with the histological size-distribution of ovarian follicles were compared among three groups of post-parturient rats nursing 0, 2 or 8 pups. From Days 4 to 12 (day of parturition = Day 0 of lactation), in dams nursing 8 pups, follicles larger than 401 microns in diameter were absent, whereas follicles of this size were always present in mothers nursing 0 or 2 pups. The in vitro production rates of estradiol-17 beta (E2) and testosterone (T) by nonluteal ovarian tissues (NLO) were consistently lower in dams nursing 8 pups than in mothers nursing 0 or 2 young, correlating with the histological observations. Serum E2 and 20 alpha-dihydroprogesterone (20 alpha-OHP) in rats with 8 pups were significantly lower, whereas serum progesterone (P) was significantly increased compared to the values in dams nursing 0 or 2 pups. In mothers nursing 8 pups, the corpora lutea (CL) of lactation, formed at postpartum ovulation, produced in vitro significantly greater amounts of P but significantly lesser amount of E2 compared to the other groups. Serum luteinizing hormone (LH) was consistently lower in dams nursing 8 pups than in dams nursing 0 or 2 pups. There was, however, no significant difference in serum follicle-stimulating hormone (FSH) among the 3 types of postparturient rats. Throughout lactation serum values of FSH were within the range of diestrous levels during the estrous cycle. Serum levels of prolactin (Prl) in dams nursing 8 pups were strikingly higher compared to dams nursing 2 pups. The administration of small doses of human chorionic gonadotropin (hCG) or ovine LH twice daily from Days 2 to 5 to lactating rats nursing 8 pups induced the maturation of follicles capable of ovulating. These findings indicate that during the first half of lactation the strong suckling stimulus reduces serum LH directly or indirectly via high levels of serum Prl and P, which in turn inhibit follicular maturation. During the second half of lactation, the suckling stimulus wanes, Prl and P decline and serum LH recovers to basal cyclic values which are reflected in the initiation of follicular maturation.

Superovulation induced by a single pituitary gland transplanted beneath the kidney capsule in adult rats

Different numbers of rat pituitary glands, taken from male and female rats before and after puberty, were transplanted into various sites in female rats at different stages of the oestrous cycle. Ovulation was checked by counting ova in oviducts on the next expected day of ovulation. Ovulation was induced by transplantation beneath the kidney capsule in early dioestrus of half, one or three glands from 35- to 41-day-old male rats (18.6+/-3.1 (S.E.M.), 32.6+/-2.8 and 49.8+/-4.8 ova shed respectively). The transplantation of glands from mature female rats did not induce supraovulation but inhibited the expected ovulation. The most effective stage for inducing superovulation was early dioestrus and, to a lesser extent, most effective stage for inducing superovulation was early dioestrus and, to a lesser extent, oestrus; transplantation during late dioestrus was ineffective. The effective sites of transplantation were beneath the kidney capsule and intramuscularly but not subcutaneously. Representative pituitary glands from 35- to 41-day-old male rats and adult female rats were assayed for LH and FSH content to interpret the mechanisms of superovulation . The pituitary glands from the male rats contained larger amounts of LH and especially of FSH than those found in the female rats. The experiments indicated that superovulation can be induced successfully by the transplantation of a single pituitary gland from male and immature female rats without any additional treatment with human chorionic gonadotrophin; the failure of the female pituitary transplants to induce superovulation may be due to the insufficient content of LH and FSH.

Postovulatory steroidogenesis after PMS-induced ovulation in immature female rats

Thirty-day-old rats given a single subcutaneous injection of 5 IU pregnant mare serum gonadotropin (PMS) at 0900 h ovulated on the morning of day 33 (= estrus). However, the second ovulation did not occur until 9.4 days later. To determine the mechanism responsible for the delay in the second ovulation, in vivo and in vitro determinations of steroid and peptide hormones were compared between PMS-primed immature rats and adult cyclic rats. In PMS-primed rats, the corpora lutea (CL) produced progesterone for 2 days longer (until day 36) than the CL of the adult rat. Serum levels of 20 alpha-dihydroprogesterone, testosterone, and estradiol in PMS-primed rats were significantly lower than the corresponding values in adult rats. Serum LH was consistently lower in the PMS-primed rats. An increase in serum FSH occurred on days 36-37, which may be responsible for maturation of the follicles destined to ovulate at the second ovulation. On day 37, the nonluteal ovary of the PMS-primed rats also began to produce in vitro appreciable amounts of testosterone and estradiol. These findings suggest that the greater levels of prolactin and/or low levels of luteinizing hormone during estrus in PMS-primed rats may be responsible for the prolonged secretion of progesterone by the CL. This in turn inhibits follicular maturation, indirectly by lowering serum LH, which is reflected in reduced ability of the follicles in vitro to produce testosterone and estradiol until the CL regress.

A neglected problem: kinetic size constancy

Size constancy in three-dimensional motion, "kinetic size constancy", was investigated by measuring both perceived size and perceived distance under monocular and binocular viewing conditions. It was found that forward-motion facilitated a tendency to see an object with an approximately constant size and made it possible to perceive veridically the distance to the object (distance constancy). The size-distance invariance hypothesis, expressed in the form S'/D'=K theta n, was found to hold in the present experimental situation. In contrast to static size constancy, with kinetic size constancy there is no requirement for separate depth cues if a focal stimulus changes along its vertical and horizontal dimensions and this results in the perception of a shape.

Acute effects of exogenous progesterone on follicular steroidogenesis in the cyclic rat

The effects of exogenous progesterone (P) on follicular steroidogenesis and serum gonadotropins in the cyclic rat were determined using in vivo and in vitro approaches. A single sc injection of 800 micrograms progesterone at 0900 h on diestrus II (day 0) consistently postponed ovulation by 24 h in 4-day cyclic rats, with no change in the ovulation rate. The preovulatory surges in serum LH and FSH were delayed by 1 day and occurred on day 2 in the P-treated animals. After the injection of 800 micrograms P at 0900 h on diestrus II, peak serum levels of P were reached 3 h later and thereafter decreased to basal levels by 1500 h on day 1. Within 1 h after injecting P, serum LH and FSH decreased to values below control levels; serum LH did not recover during the next 48 h, whereas serum FSH returned to basal levels within 6 h. An abrupt fall in serum 17 beta-estradiol occurred within 1 h after the administration of P. This drastic decline in serum estradiol was paralleled by temporally related decreases in serum LH and FSH but not by changes in serum testosterone. By 0900 h on day 1 (24 h after P injection), serum and estradiol returned to values within the range observed on diestrus II, then gradually increased to proestrous values by day 2. Within 3 h after the administration of P, the initial content and the in vitro production rate of P, testosterone, and 17 beta-estradiol by antral follicles decreased in the P-treated animals compared to that in follicles of control animals, whereas the follicular content the production rate of 20 alpha-dihydroprogesterone were unaffected. Thus, in the cyclic rat, the inhibitory effects of exogenous P on follicular steroidogenesis are mediated in this dose range through the hypothalamic-pituitary axis, especially via lowering serum LH.

Pituitary function during pseudopregnancy and lactation in the rat

Plasma concentrations of FSH on Days 1, 2, 3, 8 and 9 of lactation (day of parturition = Day 0) were significantly higher than on the corresponding day of pseudopregnancy (day of vaginal plug = Day 1). Pituitary FSH content on Days 4-12 of lactation was also significantly higher than in pseudopregnant rats. However, pituitary LH content on Days 2-12 of lactation was significantly lower than in pseudopregnancy, whereas plasma concentrations of LH were almost similar. Two consecutive injections of LH-RH (100 ng/rat, i.v.), 60 min apart, resulted in a significant release of FSH in lactating rats (Days 3 and 15) in response to the second injection of LH-RH, but there was no increase in pseudopregnant rats on Day 3. The first and second injections of LH-RH produced significantly less release of LH on Days 3 and 15 of lactation than on Day 3 of pseudopregnancy. These results indicate that FSH secretion is not suppressed by suckling whereas the suckling stimulus is a potent inhibitor of LH.

Absence of prolactin surge during the period of premature ovulation induced by human chorionic gonadotropin or luteinizing hormone releasing hormone in diestrous rats

The concentration of plasma prolactin during the period of premature ovulation induced by human chorionic gonadotropin (HCG) or luteinizing hormone releasing hormone (LH-RH) in diestrous rats was determined at 3 hr intervals from 1700 hr on the day of diestrus (day 0) to 2300 hr on the day of proestrus (day 1). Premature ovulation was induced by either a single injection of 10 IU HCG at 1700 hr on day 0 or three injections of 1 microgram LH-RH at 1 hr intervals from 1700 to 1900 hr on day 0. In saline-treated controls, the concentration of prolactin in plasma was low during diestrus but increased on the afternoon of proestrus with a peak value at 1700 hr, followed by an abrupt decline at 2300 hr on the same day. However, there was no significant rise in the plasma prolactin level throughout the period of observation in HCG-treated rats. In the LH-RH treated group, the prolactin level in plasma did not change until 1100 hr on day 1, but significantly increased at 1400 hr on the same day then declined by 2300 hr, though no significant difference was observed at any time when compared to HCG-treated rats. These results indicate that no prolactin surge occurred during the period of premature ovulation.