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The cooperative action of sodium orthovanadate (a putative protein-phosphotyrosine phosphatase inhibitor) and rutin (an effective superoxide scavenger) on the nitric oxide (NO) production of J774A.1 mouse macrophage cells has been investigated. Orthovanadate alone caused a mild but significant increase in NO production of the cells at its highest concentration used (500 microM). Orthovanadate and rutin together caused a significant increase in the nitrite level of the supematants of the J774A.1 cells after a 24-hour incubation period, in a concentration dependent manner. The optimal doses for orthovanadate and rutin were 50 microM and 100 microM, respectively. This cooperative action of rutin and orthovanadate was totally inhibitable by catalase, reduced glutathion, N-acetylcystein, cycloheximide, pyrrolidine dithiocarbamate (a putative NF-kappaB inhibitor), genistein and tyrphostin-AG126 (two protein tyrosine-kinase inhibitors). Superoxide dismutase had no inhibitory effect. Orthovanadate and rutin (only together) could induce the oxidation of 2',7'-dichlorofluorescein-diacetate, a marker of hydrogen peroxide. This effect was inhibitable by reduced glutathion, a hydrogen peroxide specific scavenger. These findings suggest, that orthovanadate can induce the production of NO by J774A.1 macrophages not only by inhibition of protein tyrosine-phosphatases, but, using it with rutin, by increasing the level of hydrogen peroxide in the cells.

Ipriflavone [CAS No.: 35212-22-7] is a novel drug used in the treatment of osteoporosis successfully. However, its mechanism of action has not been fully clarified yet. We investigated the effects of ipriflavone and its metabolites (I, II, III, V, VI, VII) on lipopolysaccharide (LPS)-induced nitric oxide (NO) release from RAW-264.7 mouse macrophage cells. Our data show that the LPS-induced NO release from RAW-264.7 cells was significantly inhibited by ipriflavone metabolite-III [7-isopropoxy-3-(4-hydroxyphenyl)-4H-1-benzopyran-4-one], [CAS No.: 97846-18-9] in a dose (3 x 10(-8)-10(-5) M)-dependent manner. Ipriflavone itself and its other metabolites had much lower inhibitory effect on the LPS-induced NO release from RAW-264.7 cells. The IC50-value of ipriflavone metabolite-III (1.0 x 10(-6) M) was between the IC50-values of the two reference compounds dexamethasone (4.0 x 10(-8) M) and NG-Nitro-L-arginine (L-NNA, 7.5 x 10(-5) M). Our finding suggests that some of the beneficial effects of ipriflavone in the treatment of osteoporosis might be mediated by its metabolite-III.

It has been demonstrated that the novel antihypertensive compounds GYKI-12743 showed a potassium channel opening effect as studied in rabbit ear arteries with 86Rb+ as K+ marker. GYKI-12743 produced a concentration dependent 86Rb+ efflux in the same concentration range as the well-known K(+)-channel openers, pinacidil and cromakalim.

In CFY rats pseudopregnancy (PSP) was induced by mechanical stimulation of cervix uteri. On the days 1 or 7 of PSP indvelling catheter was built in one of the jugular veins and blood was collected daily until 7th or 14th days of PSP respectively, meanwhile the animals were daily injected with clenbuterol (0.1 mg/kg bw), fenoterol (0.5 mg/kg bw), ritodrin (1.0 mg/kg bw), propranolol (2.0 mg/kg bw) or 1.0 ml/kg bw 0.9% NaCl subcutaneously. From the blood samples progesterone (P) and oestradiol-17 beta (E2) were determined by RIA. beta 2-adrenergic agonists did not influence the serum levels of P either in the first or in the second half of PSP and the propranolol failed to alter also the serum levels of P during the PSP. Clenbuterol and ritodrin, however, decreased the serum levels of E2 in the first half of PSP, while in the second half of PSP fenoterol and ritodrin elevated, the propranolol diminished it. It was supposed that in PSP rats beta 2-adrenergic mechanism has a more pronounced effects on the theca-interstitial cells than that of the luteal cells.

Using the pithed rat preparation it has been proven that GYKI-12743 exerted its alpha-adrenergic blocking action only at the postsynaptic vascular level in the cardiovascular system. This new molecule failed to antagonize the presynaptic alpha 2-adrenoceptors of the cardiac sympathetic nerve endings. Thereby it was possible to demonstrate the first vasoselective postsynaptic adrenoceptor antagonist which potentially might be interesting in the cardiovascular therapy.

Oestrous rats and golden hamsters were anesthetized with pentobarbital, one of the femoral arteries and veins and one of the ovarian veins were cannulated. Blood fractions were collected from the ovary. After the first two fractions synthetic adrenocorticotropic hormone (ACTH) or human chorionic gonadotropin (hCG) was injected i.v. Blood pressures and ovarian blood flow were continuously recorded. Progesterone (P) and oestradiol-17 beta (E2) were determined from the ovarian venous blood by radioimmunoassay (RIA). ACTH induced a temporary elevation in the ovarian blood flow, P and E2 secretion both in rats and hamsters. In rats and hamsters hCG induced a continuous elevation in P secretion but the ovarian blood flow and E2 secretion remained unchanged. Luteal cells from pseudopregnant rats or oestrous hamsters were dispersed with collagenase and incubated with ACTH or hCG. A sample of the cells was preincubated with polymixin-B, indomethacin or ibuprofen. P and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) contents of the medium and cyclic 3,5 adenosine monophosphate (cAMP) content of the cells were determined by RIA. ACTH stimulated the release of 6-keto-PGF1 alpha and the secretion of P from the luteal cells of both species, which was inhibited by indomethacin or ibuprofen, but ACTH did not alter the cAMP content of luteal cells. The polymixin-B prevented ACTH to stimulate P secretion, but it did not elevate the 6-keto-PGF1 alpha release, while the cAMP content of the cells remained unchanged. It is supposed that the polyphosphoinositol-Ca(2+)-protein kinase-C second messenger system is involved in the ACTH induced stimulation of P secretion.

We have summarized the data of our former experiments which clearly demonstrate that ACTH increases ovarian blood flow in various mammals. Furthermore, when the ovary is primed with gonadotropic hormones it stimulates secretion of 17 beta-oestradiol and progesterone.

Pseudopregnant rats were anaesthetized on day 5 of pseudopregnancy with pentobarbital and hypophysectomy or sham operation was performed. Polyethylene cannulas were inserted into one of the femoral arteries and utero-ovarian veins. Five-minute blood samples were collected from the ovary for 40 minutes. Following the first five minute blood fraction LH-RH, an agonistic analogue (D-Phe6, des Gly-NH10(2)-LH-RH-ethylamide) or an antagonistic analogue (Formyl-D-Tryp1,3, D-pCl-Ph2, D-Phe6LH-RH) were superfused into the ovarian bursa for 5 minutes in a volume of 50 microliters. Blood pressure, ovarian venous outflow and haematocrit were continuously measured. From the blood samples progesterone and oestradiol-17 beta were determined by RIA and the secretion rate was calculated. It was found, that LH-RH and its antagonistic analogue has no effect on the blood flow, progesterone (P) and oestradiol-17 beta (E2) secretion of ovary. However, an agonistic analogue of LH-RH induced a rapid elevation of blood flow, diminished vascular resistance in the ovary, and in a dose of 50 ng increased the secretion rate of E2. In sham operated animals the effects of agonistic analogue was similar to the effects of 1.0 IU of hCG.