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Biomedical subjects

F Di Carlo

Publications and source records attributed to F Di Carlo.

At least 37 records · Page 2Linked to original sources
PubMed1984

Effects of long-term administration of high doses of medroxyprogesterone acetate on hormone receptors and target organs in the female rat.

The changes in oestrogen, progesterone and prolactin receptor levels in target organs, and the macroscopic and microscopic modifications of uterus, ovary, adrenal and pituitary gland induced by long-term administration of high doses of medroxyprogesterone acetate (MPA) were investigated in female rats. Medroxyprogesterone acetate was injected i.m. for 30 days at daily doses of 7.5, 15 and 75 mg/kg. Oestrogen and/or progesterone-binding capacities were remarkably reduced at all doses of MPA used both in the uterus and pituitary gland. Furthermore, MPA caused a very evident reduction in the weight of pituitary glands, ovaries, adrenals and uterus. In all MPA-treated rats corpora lutea were absent from the ovaries, whereas the adrenals showed a significant reduction in the thickness of the cortex. In accordance with this, there was no evidence of ACTH-producing cells in the pituitary glands. Prolactin-producing cells were also absent, while GH-producing cells were present. Serum prolactin levels were significantly reduced at all doses of MPA used. A dramatic reduction of prolactin receptor concentrations was observed in the liver and the ovaries of MPA-treated rats. The results suggest that MPA acts as an antioestrogenic drug both by reducing the number of oestrogen receptors in target tissues and by changing the structure (and perhaps the function) of those organs (pituitary glands, ovaries and adrenals) which are, directly or indirectly, a source of oestrogens. The decreased synthesis of prolactin and the reduction of the number of prolactin receptors (which, on the contrary, are both increased by oestrogens) might be considered as additional antioestrogenic effects of MPA.

Adrenal Glands↗
PubMed1983

Effects of bromocriptine and dopamine on the binding of estradiol to its uterine cytoplasmic receptors.

The in vivo and in vitro effects of bromocriptine on the binding of estradiol 17 beta to its specific uterine receptors were studied in both mature and immature rats. A single i.p. injection of bromocriptine reduced the specific estradiol-receptor interaction in adult rats, while it resulted ineffective in prepubertal animals. The effect of bromocriptine in mature rats was dose-dependent and evident only when using a dose of at least 0.70 mg/kg. Experiments in vitro also showed that in mature rats bromocriptine affected the estradiol-receptor interaction inducing a decrease in binding, which is well correlated to the concentration used. On the contrary, no effect of bromocriptine in vitro was observed when using cytosol obtained from uteri of immature rats. Very similar results were obtained in experiments in vitro when using dopamine instead of bromocriptine. Our results suggest that apparently there are two forms of estrogen receptors, one present both in prepubertal and pubertal age and the other present only in mature animals. The latter is the type of receptor sensitive to both bromocriptine and dopamine and presumably develops under the control of hormonal factors, which are only present at puberty.

Animals↗
PubMed1983

Changes in the binding of oestradiol to uterine oestrogen receptors induced by some progesterone and 19-nor-testosterone derivatives.

The effects of two progesterone derivatives, namely medroxyprogesterone acetate (MPA) and chlormadinone, and two 19-nor-testosterone derivatives, namely norgestrel and norethisterone, on the binding of oestradiol to its cytoplasmic receptors in the rat uterus were compared. In experiments performed in vivo, the rats were given a single oral dose (15 mg/kg) of one of the four progestins and killed 1, 6, 24 and 48 h later. Norgestrel, norethisterone and MPA induced a prompt and remarkable decrease in oestradiol-receptor interaction 1 h after treatment. This reduction lasted almost unchanged for 24 h in rats treated with MPA or norgestrel, but was much lower in animals given norethisterone. In the hours that followed, the effect of MPA and norgestrel began to decrease, but was still detectable after 48 h, whereas the effect of norethisterone had disappeared by this time. The effect of chlormadinone was much less than that induced by both MPA and norgestrel 1, 6 and 24 h after treatment. On the other hand, this effect was less than that caused by norethisterone 1 h after administration, equal after 6 h and much greater after 24 and 48 h. In experiments performed in vitro, the different ability of the four progestins to interfere with the capacity of oestradiol to bind to its receptors was confirmed. In conclusion, all the synthetic progestins used were able to reduce the binding of oestradiol to its cytoplasmic receptors, although there was a clear difference between the progestins in the intensity and duration of this effect. This could be one of the mechanisms by which progestins modulate the activity of oestrogens in target tissues.

Animals↗
PubMed1983

The correlation between estrogen receptor status, axillary-node metastases and disease-free interval after surgery in primary breast cancer.

The prognostic value of estrogen receptor (ER) status in primary breast cancer was evaluated in 208 women subjected to Halsted radical mastectomy. The correlation between ER status, node involvement and disease-free interval after surgery was analyzed in detail. Forty-seven out of 127 ER-positive patients received hormonal adjuvant therapy, whereas the 81 ER-negative patients did not. Similar recurrence rates were found in ER-negative and untreated ER-positive patients, suggesting that the natural course of disease was not related to ER status. ER-positive patients who received hormonal adjuvant therapy showed a significantly longer disease-free interval than both ER-negative and untreated ER-positive patients, even though a higher frequency of node involvement was found in ER-positive tumors. Since only hormone-treated ER-positive patients showed a significantly lower recurrence rate, it is felt that ER status cannot be used as an independent prognostic factor.

Adult↗
PubMed1980

Effects of estrogens P-1496 and P-1560 on the binding of estradiol with rat uterine estrogen receptors.

The interference of two weak estrogens (P-1496 and P-1560) on the binding of estradiol with uterine estrogen receptors is comparatively studied. Both P-1496 and P-1560 decrease the estradiol binding capacity, but P-1560 is less effective than P-1496. Since P-1496 is a more potent estrogenic substance than P-1560, the results obtained confirm that the uterotrophic activity of estrogens is related to the binding capability to uterine estrogen receptors.

Animals↗
PubMed1978

Interference of gestagens and androgens with rat uterine oestrogen receptors.

The inhibitory effect of some gestagens and calusterone on the binding of oestradiol-17beta to its specific uterine receptors has been investigated in intact rats. Progesterone, medrogestone, clogestone, medroxyprogesterone acetate and calusterone reduce the specific oestradiol-receptor interaction in vitro; this effect is dose-dependent and does not differ significantly from one drug to the other. A more relevant decrease in the amount of oestradiol-17beta bound to specific receptors has been observed with calusterone. Progesterone, clogestone, medrogestone, medroxyprogesterone acetate and calusterone given orally induce a marked decrease (between 30 and 70% depending on the dose) in the binding capacity of oestradiol-17beta to specific uterine receptors in vivo. Results from a Scatchard plot analysis suggest that the interference with the binding of oestradiol-17beta caused by both progestogens and calusterone is due to a non-competitive interaction.

Animals↗
PubMed1978

Changes in the concentration of uterine cytoplasmic oestrogen receptors induced by doxorubicin and methotrexate.

The effects of doxorubicin and methotrexate on the oestradiol-induced depletion, replenishment and subsequent increase beyond the normal value (overshoot) in the number of uterine cytoplasmic oestrogen receptors were investigated in intact rats. Injection of doxorubicin (0.5 mg/kg, i.v.) or methotrexate (1mg/kg, i.m.) 5 min after a single i.p. injection of 10 ng oestradiol-17beta (which is able to induce a 50% depletion in the number of oestrogen receptors) caused a significant increase in the oestradiol-induced depletion. Both drugs inhibited the replenishment and the overshoot phases until 48 h after treatment, although the effect was more marked with doxorubicin. Experiments in vitro showed that both methotrexate and doxorubicin affected the capacity of oestradiol-17beta to bind to specific cytoplasmic receptors, inducing an increase in binding when used at low concentrations and a decrease at higher concentrations. The effects of doxorubicin and methotrexate on the depletion, replenishment and overshoot of oestrogen receptors seemed to be partly dependent on the inhibition of protein synthesis and partly due to direct action on the binding of oestradiol-17beta to its receptors.

Animals↗
PubMed1977

[Preliminary results of treatment of hormone-dependent metastatic carcinoma of the breast with the bromocriptin-medroxyprogesterone acetate combination].

A brief account of the concept of hormone dependence in breast neoplasia is followed by the presentation of results obtained with an association of medroxyprogesterone acetate (MAP) and 2-bromo-alpha-ergocriptine (CB 154) in 14 women with metastatic cancer of the breast, hormone dependent due to the presence of the cytoplasmic receptor for 17-beta-oestradiol. All patients, in fertile or premenopausal stage, were subjected to prior surgical ovariectomy. MAP was given i.m. at a dose of 1 g/day for 30 days and then 150 mg/day. In the same time 2.5 mg CB 154 were administered every 6 hr per os. Evaluation in accordance with the criteria proposed by the Coop Breast Cancer Group showed that rapid improvement was obtained in all cases, persisting (at the time of writing) for a minimum of 6 months to a maximum of 2 yr of observation. In addition, rapid disappearance of pain was noted, particularly in subjects with secondary bone lesions. Side-effects were in all cases of slight consequence and suspension of the treatment was never necessary. The mechanism of the two drugs and the advantages of their association are discussed.

Adult↗
PubMed1977

Production of casein and the presence of estrogen receptors in human breast cancer.

The relationship between the presence of estrogen receptors and casein (evaluated on a semiquantitative basis with a specific immunofluorescence method) was statistically analyzed in 50 cases of human breast carcinomas. No significant correlation was found between these two parameters, whereas a relationship was established between the production of casein and the degree of histological differentiation. The results of this study, like those of other studies, revealed a lack of correlation between the presence of estrogen receptors and the degree of histologic differentiation.

Breast Neoplasms↗