Cyclic AMP-phosphodiesterase and epidermal mitosis.

The relationship between cyclic AMP-phosphodiesterase (cAMP-PDE) inhibition and inhibition of epidermal mitosis was examined for several compounds using a soluble, low Km PDE activity from hairless mouse skin and the G2 mouse ear mitosis assay. Orders of potency determined at IC50 levels (concentrations required for 50% inhibition) were SQ 20009 greater than RO 20-1724 greater than papaverine greater than bufexamac greater than indomethacin greater than theophylline greater than p-biphenylylacetic acid greater than or less than glycyrrhetinic acid for inhibition of both PDE and mitosis. The disproportionately high antimitotic potency of puromycin relative to PDE inhibition was believed to reflect effects on protein biosynthesis. Activity of the three nonsteroidal anti-inflammatory agents (bufexamac, indomethacin, and p-biphenylylacetic acid) was unrelated to their effect on prostaglandin synthesis in homogenates of hairless mouse skin. The results suggest that the epidermal antimitotic activity of the compounds tested is related to their inhibition of cAMP-PDE and provide additional support for cAMP as a regulator of the G2 stage of the epidermal cell cycle.

Inhibition of rabbit platelet phosphodiesterase activity and aggregation by calcium channel blockers.

Rabbit platelet cyclic AMP phosphodiesterase is inhibited by the three calcium channel blockers nifedipine, diltiazem, and verapamil with IC50's of 100 microM, 100 microM and 420 microM, respectively. Also, platelet aggregation induced by 4 microM ADP is inhibited by those compounds. Verapamil is the most potent aggregation inhibitor with an IC50 of 260 microM while diltiazem and nifedipine have IC50's of 630 microM and 840 microM, respectively. All three compounds display a maximum inhibition of 80-85%. Diltiazem and PGD2 potentiate the antiaggregatory activity of each other in that the inhibitions occurring in the presence of the combination of the two (at varying concentrations) exceed the calculated sums of the inhibitions produced by each alone. On the other hand, the antiaggregatory activities of verapamil or nifedipine, are additive with that of PGD2 in that no significant differences exist between the observed inhibitions produced by the combinations and the calculated summed values of the individual inhibitions. Our data suggest, therefore, that in addition to lowering intracellular calcium ions, which are required for platelet aggregation, the three calcium channel blockers inhibit the breakdown of cyclic AMP thereby promoting antiaggregation.

Multiple sites of interaction between prostaglandins and non-steroidal anti-inflammatory agents.

Several non-steroidal anti-inflammatory agents (NSAIA) are shown to inhibit the net production of prostaglandin (PG)- like activity from arachidonic acid by a cell-free preparation of guinea-pig lung. Moreover, these agents also antagonize PGE-1-induced contractions of the isolated gerbil colon. The anti-spasmogenic effects are reversible and specific. At high concentrations, indomethacin and mefenamic acid interfere with the binding of PGE-1 to a broken cell preparation of rat epididymal adipocytes. Taken together the data indicate that NSAIA interact with prostaglandins at multiple sites and are consistent with the suggestions reported previously that NSAIA may have multiple in vivo actions.

Prostaglandin E antagonist activity of 11-deoxy-16,16-trimethyleneprostaglandin E1.

11-Deoxy-16,16-trimethyleneprostaglandin E1 is a potent inhibitor of prostaglandin E-induced contractions of the gerbil colon. The antagonism is directed specifically against the prostaglandin E receptor and is not manifested when contractions are induced by either prostaglandin F2 alpha or acetylcholine.

Effect of various pharmacological agents on prostaglandin induced increases in microvascular permeability.

The anti-histamines, pyrilamine and chlorpheniramine, the serotonin antagonist, methysergide, the beta-adrenolytic, phenoxybenzamine and the anti-cholinergic, atropine, antagonized the prostaglandin E1 induced increases in vascular permeability. None of the non-steroidal anti-inflammatory agents acted as antagonists at these doses.

Enhanced insulin secretion and calcium uptake by Zucker "fatty" rat islets.

The relationship of the net uptake of calcium to insulin secretion by pancreatic islets isolated from Zucker "fatty" rats and their lean counterparts was studied. Islets from "fatty" rats secreted 1.5 to 3 times as much insulin as did the lean rat islets over a glucose concentration range of 0 to 27.7 mM. Over the same glucose concentration range, calcium accumulation was 2-fold greater in islets from the "fatty" rats than from the others. Both insulin secretion and calcium uptake were 2 to 3 fold greater for islets from the "fatty" rats than those from the lean animals over an extracellular calcium concentration range of up to 5 mEq/L. The data indicate that for islets isolated from Zucker "fatty" rats insulin hypersecretion in response to glucose and extra-cellular calcium is associated with enhanced calcium accumulation.

Growth hormone stimulation of amino acid transport and utilization by the perfused rat liver.

The effects of growth hormone, administered in vivo or added in vitro, on amino acid transport and utilization have been studied in perfused livers of normal and hypophysectomized rats. A perfusion system employing a nonrecirculating medium was used in all of the studies. Two nonmetalbolizable amino acid analogues, alpha-aminoisobutyric acid (AIB) and 1-aminocyclopentane carboxylic acid (cycloleucine) were used to study transport. Accumulation of AIB increased linearly over a 60-min perfusion period, reaching distribution ratios of between 1 and 2 for both groups of animals. Treatment of both normal and hypophysectomized rats with growth hormone 60 min prior to the start of perfusion increased AIB distribution ratios by up to 84 and 108%, respectively. Accumulation of cycloleucine was linear for only about 20 min of perfusion and then plateaued. Steady state distribution ratios of this analogue ranged between 1 and 2 for both groups of animals. Growth hormone treatment had no apparent effect on the time necessary to reach these steady state levels, but significantly increased them in livers of both normal and hypophysectomized rats by 16 and 42%, respectively. Studies designed to analyze the kinetic properties of these hormone effects revealed that growth hormone treatment caused 2-fold i-crease in the maximum velocities of both the AIB and cycloleucine transport systems. The substrate concentration for half-maximal transport velocity was increased slightly for both systems by growth hormone. Direct effects of growth hormone were demonstrated in studies where livers of hypophysectomized rats were perfused under conditions simulationg those of experiments in which the hormone was administered in vivo. Following an initial 45-min period of perfusion the medium during the 20 min. Growth hormone added to the medium during the entire 65-min perfusion at a concentration of 1 mug per ml caused a 30% increase in the cycloleucine distribution ratio. Under similar experimental conditions growth hormone directly stimulated three hepatic pathways of amino acid utilization: (a) incorporation of [14C]valine into protein, (b) urea formation and (c) conversion of 14-C-amino-acids to labeled glucose. Intracellular concentrations of seven amino acids, including threonine, serine, proline, glycine, alanine, lysine, and arginine, were increased significantly in livers perfused with medium containing growth hormone...

Potent and selective effects of suprofen on uterine prostaglandin synthesis.

Suprofen is a non-narcotic, peripheral analgesic that exhibits potent prostaglandin (PG) synthesis inhibitory activities in a variety of subcellular tissue preparations and in vivo. The results of the present study show suprofen to be significantly more potent than either ibuprofen (6-fold) or aspirin (1000-fold) as an inhibitor of PG production by cell-free preparations of guinea pig uteri. It is selectively more potent against the production of PGF2 alpha and PGE2 than against the formation of 6-keto PGF1 alpha, the stable metabolite of prostacyclin. Suprofen is markedly more potent inhibiting the conversion of arachidonic acid to PGF2 alpha than is ibuprofen (30 times) or aspirin (1250 times). Taken together with the important role PGF2 alpha plays in the etiology of dysmenorrhea and the observation (Hahn et al., 1982) that suprofen is more potent and effective than a number of other PG synthesis inhibitors, including ibuprofen and aspirin, at reducing in vivo guinea pig uterine contractions induced by arachidonic acid, the results of the present study suggest a mechanism to support the clinical findings that suprofen is a very effective treatment for the signs and symptoms of dysmenorrhea.

Prostaglandin E antagonist activity of 11, 15-bisdeoxy prostaglandin E1 and congeners.

d,l-11, 15-bisdeoxy PGE1 and certain of its congeners were shown to inhibit gerbil colon contractions induced by l-PGE1. While some of these compounds were selectively antagonistic of PGE1-induced contractions, others additionally inhibited the gerbil colon agonist activities of l-PGE2alpha and acetylcholine. The PGE1 inhibitory activity was apparently competitive in nature. With relatively weak potencies, the bisdeoxy PGE congeners displaced 3H-PGE1 from a fat cell binding site, suggesting competition for a common, putative receptor. Structure-activity relationships and potential utility of these analogs are discussed.

The pharmacological properties of fenbufen. A review.

gamma-Oxo(1,1'-biphenyl)-4-butanoic acid (fenbufen) was shown to be an orally and parenterally effective nonsteroidal antiinflammatory, analgesic and antipyretic agent in a variety of animal species. Like other clinically active antiinflammatory drugs such as acetylsalicylic acid (ASA), indometacin and phenylbutazone, fenbufen has demonstrated potent activity in a variety of laboratory test systems including carageenin edema (rats), UV erythema (guinea pigs), adjuvant arthritis (rats), urate synovitis (dogs), phenylquinone writhing (mice), and yeast-induced pyresis (rats). In general, fenbufen was less potent than indomethacin and more potent than ASA, and appeared of special interest because of its high analgetic efficacy and long duration of antiinflammatory and analgetic action. While shown to have ulcerogenic potential in rats at toxic doses, fenbufen was less potent than indometacin in this respect and had a superior margin of gastrointestinal safety in treatment of dogs with urate synovitis. One of fenbufen's major metabolites, 4-biphenylacetic acid (BPAA), was found to be potent inhibitor of prostaglandin (PG) synthesis both in vitro and in vivo with a variety of tissues tested. Fenbufen itself was devoid of this anti-PG-synthetase activity although it interacted with prostaglandins in other ways. These results, coupled with the fact that only BPAA showed pharmacological activities when applied locally, led to the conclusion that BPAA was the principle responsible for fenbufen's antiinflammatory action. Fenbufen thus appears to be a pro-drug capable of circumventing at least some of the gastric toxicity usually incurred when compounds, which are themselves capable of inhibiting PG synthesis, are introduced directly into the stomach. Fenbufen's relatively low gastric toxicity in dogs and humans seems to substantiate this hypothesis. The pharmacological evidence indicates that fenbufen should be a highly effective and clinically useful antiinflammatory, analgetic and antipyretic drug.

Altered susceptibility of arthritic rats to the gastric lesion-inducing effects of aspirin or ethanol and the antilesion effect of rioprostil.

It is well known that nonsteroidal antiinflammatory agents produce gastric mucosal lesions in both laboratory animals and man. However, the effect of an arthritic condition on their susceptibility to ulcerogenic agents and on the efficacy of antiulcer agents is less definitive. As a model to explore these questions, the effect of oral administration of aspirin or ethanol on gastric lesion formation was examined in rats with or without established adjuvant-induced polyarthritis. In addition, the antilesion efficacy of rioprostil, a primary alcohol prostaglandin E1 analog, was evaluated in both groups of rats. The results demonstrated that arthritic rats were more sensitive to the lesion-inducing effect of aspirin, but were more resistant to the lesion-inducing effect of ethanol when compared to normal rats. An increase in endogenous gastric prostaglandin production in arthritic rats may account for their relative resistance to ethanol. Aspirin inhibited the prostaglandin synthetic capacity of the stomach in both normal and arthritic rats, which may be responsible for eliminating the relative resistance of arthritic rats to gastric irritation. Rioprostil effectively prevented aspirin or ethanol-induced lesion formation in both arthritic and nonarthritic rats, but its potency against either irritant was decreased in arthritic rats.

Inhibition of prostaglandin-mediated ocular inflammatory responses by 4-biphenylacetic acid.

4-Biphenylacetic acid (BPAA),a prostaglandin-synthesis inhibitor, was tested for its effects on prostaglandin-related, laboratory models of ocular inflammation. Topically applied, BPAA inhibited arachidonic acid, but not prostaglandin E-induced increases in rabbit intraocular pressure (IOP). BPAA inhibited the IOP response to alkali burn and altered IOP changes following paracentesis. In vitro, BPAA inhibited prostaglandin production from arachidonic acid in cell-free preparations of rabbit uvea. It is suggested that BPAA may be useful for the therapy of ocular inflammatory disease.

Suprofen: the pharmacology and clinical efficacy of a new non-narcotic peripheral analgesic.

Suprofen is a potent, peripherally-acting, non-narcotic analgesic agent. The mechanism of action of the compound involves inhibition of prostaglandin biosynthesis and, perhaps, direct antagonism of the peripheral, pain inducing actions of prostaglandins, bradykinin and other pain mediators. Suprofen at a dose of 200 mg appears to be equal or greater in efficacy as an analgesic modality than those of ibuprofen, propoxyphene, naproxen and diflunisal or a combination of 650 mg aspirin plus 60 mg codeine. Its clinical utility has been amply demonstrated in the treatment of a number of types of pain including general and orthopedic surgery, episiotomy, post-partum pain, dysmenorrhea, dental pain and musculoskeletal disorders. Suprofen represents a new class of orally effective nonnarcotic analgesics with potential for effective clinical use in the treatment of pain.

Tissue selectivity and variability of effects of acetaminophen on arachidonic acid metabolism.

Acetaminophen has variable effects on prostaglandin synthesis depending on the tissue preparation used. The present study was designed to determine the effects of acetaminophen on arachidonic acid metabolism in different tissues simultaneously removed from the same animals treated with the compound. The ex vivo conversion of 14C-arachidonic acid into 14C-prostaglandins was monitored in homogenates or slices of tissues to which no exogenous cofactors were supplied. Administered orally at doses of 100-300 mg/kg to guinea pigs, acetaminophen stimulated prostaglandin production by cell-free preparations of stomach, but had no effect in lung or kidney medulla. At doses ranging from 25-300 mg/kg, p.o., to rats, acetaminophen stimulated stomach, but inhibited cerebral cortex prostaglandin production. These same effects were mimicked qualitatively when acetaminophen was added in vitro at 10(-4)M to 10(-2)M to similar preparations. In addition, at these same high concentrations, acetaminophen inhibited 5-lipoxygenase activity in cultured RBL-1 cells. It is speculated that the multiple and tissue variable effects that acetaminophen had on arachidonic acid metabolism depend on the inherent cofactors associated with each tissue type.

Whole body surface electron irradiation in the treatment of mycosis fungoides. An evaluation of 200 patients.

The records of 200 patients with generalized cutaneous mycosis fungoides treated with whole body surface electron irradiation were reviewed. Type of skin lesion appeared to be the most important factor with respect to both survival and generalized skin disease-free interval. High-dose irradiation did not seem to influence prognosis significantly compared with a relatively conservative dose. The "cure" rate for the entire group was 7%. For a more homogeneous dose distribution, the eight-field technique is now used instead of the original four-field method. A new formula is proposed to standardize the reporting of doses.

Pharmacologic and pharmacokinetic characteristics of norgestimate and its metabolites.

Biotransformation, pharmacologic, and pharmacokinetic studies of norgestimate and its metabolites indicate that 17-deacetyl norgestimate, along with the parent drug, contributes to the biologic response. The postulated metabolic pathway, which is based on the identification of urinary products had indicated that three metabolites of norgestimate, 17-deacetyl norgestimate, 3-keto norgestimate, and levonorgestrel, might participate in the response. The pharmacologic evaluation of these metabolites demonstrates that only 17-deacetyl norgestimate has a pharmacologic profile consistent with that of norgestimate, and significant concentrations of this metabolite have been measured in the serum of women after the administration of norgestimate. These studies indicate that 17-deacetyl norgestimate contributes to the pharmacologic response to norgestimate.

Anticandidal activities of terconazole, a broad-spectrum antimycotic.

Terconazole is a new triazole ketal derivative with broad-spectrum in vitro and in vivo antifungal activities. This study further characterizes the effects of terconazole in vitro on yeast cell growth, viability, and morphology. Terconazole inhibited the growth of Candida albicans ATCC 44859 in a concentration-related manner, but with modest effects noted at levels from 10(-8) to 10(-5) M when the yeast was grown on media favoring the cell form. The inhibitory potency of terconazole on yeast cell viability varied with the strain and species of Candida tested. The susceptibility of C. albicans ATCC 44859 to terconazole was markedly enhanced when the yeast was grown on Eagle minimum essential medium, which favors mycelium formation. The effects of terconazole on the morphology of yeast cells (grown on Eagle minimum essential medium) were shown by phase-contrast and electron microscopy. There is a progression of changes, from loss of mycelia formation at 10(-8) M terconazole through complete necrosis at 10(-4) M.