In order to elucidate the mechanism of thyroid hormone action on the ovary, direct effects of L-thyroxine (T4) or L-triiodothyronine (T3) on steroidogenic enzyme induction were investigated in vitro using a monolayer culture system of porcine granulosa cells obtained from small follicles. The cells were cultured in the absence or presence of porcine FSH (20ng/ml) for 6 days, with or without T4 or T3, under sparsely (4%) serum supplemented condition. The mechanism of thyroid hormone action on the granulosa cells was studied by testing the capability of thyroid hormone to enhance the steroidogenesis in response to exogenously provided substrates. Concomitant treatment with FSH (20ng/ml) and T4 (10(-7) M) caused a further increased production of progesterone in response to the addition of pregnenolone compared to that in the absence of pregnenolone. The same treatment with FSH and T4 also caused a further increased production of estrone in response to the addition of androstenedione. Concomitant treatment with 10(-9) MT3 demonstrated similar stimulatory effects on the steroidogenesis in cultured granulosa cells. T4 or T3 alone without FSH was incapable of exhibiting these stimulatory effects. Furthermore, aromatase activity in cultured granulosa cells assessed by the release of tritiated water from [1 beta-3H, 4-14C] androstenedione was significantly higher in the cells treated concomitantly with FSH (20ng/ml) and T4 (10(-7) M) than that in the cells treated with FSH alone. These results suggest that thyroid hormone synergizes with FSH and increases FSH-mediated induction of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) and aromatase activity in immature granulosa cells. Since the effective dose of T4 and T3 observed in our studies is in the physiological range of circulating total levels of T4 and T3, it can be concluded that the synergism between FSH and thyroid hormone is of physiological importance to the full expression of FSH actions in the functional differentiation of immature granulosa cells.

Retinoids are compounds that can elicit specific biological responses by virtue of their binding to and activating a specific receptor or a set of receptors. Retinoids produce various specific biological effects, including induction of terminal differentiation, regulation of cell proliferation, regulation of gene expression and regulation of the activity of specific enzymes in cells. In this article, the effects of retinoids on gene expression are reviewed. Among these effects suppression of myc expression and induction of EGF-receptor mRNA expression are considered to be closely related to regulation of cell proliferation. The effects of retinoids on cell growth are discussed on the basis of these two actions: myc mRNA suppression and EGFR mRNA induction. The mode of retinoidal action seems to be similar to that of steroids, as many investigators suggest. The molecular mechanism of retinoidal action is considered to be the formation of a retinoid-receptor complex and its interaction with regulatory elements of DNA. The possibility of application of the methodology used in the investigation of steroidal action to the study of retinoidal action is also discussed.

The accumulation of (2''R)-4'-O-tetrahydropyranyladriamycin (THP) was studied in rats received intravenous administration of 14C-THP at a dose of 0.5 mg/kg/day for 14 consecutive days by determining blood and tissue levels and the excretion of the radioactivity. The radioactivity levels in plasma and blood cells after the multiple administration were higher than those after single administration. The half-life of the radioactivity after the multiple administration was longer in the blood cells but not in the plasma than the half-life after a single administration. Tissue levels of the radioactivity after the multiple injection were 2 to 4 times as high as the levels after a single injection except for the brain and testes in which a large accumulation of the radioactivity was observed. However, little accumulation of unlabeled THP was found in most tissues when determined by HPLC. The accumulation of radioactivity in tissues, therefore, was due to metabolites of THP. The disposition of 14C-THP was also examined in rats which had previously received unlabeled THP (0.5 mg/kg/day) for 13 days. The pretreatment did not affect the disposition of 14C-THP seriously, although the pretreatment raised tissue levels slightly and a rebound of plasma level of 14C-THP, and lowered the fecal excretion ratio. No induction of hepatic drug metabolizing enzymes was observed in rats after repeated administrations of THP for consecutive 14 days.

To investigate the mechanisms of the tumor promoter, 12-0-tetradecanoyl phorbol 13-acetate (TPA), chromosomal change, [3H]-thymidine incorporation, DNA histogram pattern, and the cellular contents of protein, RNA, and DNA were analyzed with in vivo-in vitro assay to ethylnitrosourea (ENU) induced transplacental neurogenic carcinogenesis. The earlier appearance of chromatid breaks and exchanges was found in the ENU group treated with TPA than that in the ENU group treated with or without acetone. From the findings of cellular DNA contents and DNA histogram pattern, the rapidly increased percentage of G2-M phased population and the rapid increase of cellular DNA contents were found in the ENU group treated with TPA compared to the ENU group. And the more rapid increase of [3H]-thymidine incorporation was found in the ENU group treated with TPA than that in the ENU group. The findings of chromosomal changes, DNA histogram pattern, [3H]-thymidine incorporation, and cellular DNA content in the control group did not differ from that in the control group treated with TPA. Above results seem to be indicated that TPA might modulate the metabolism of nucleic acids and the regulation of gene expression damaged initially by ENU.

The in vitro antibacterial activities of cefoperazone (CPZ) against clinical isolates including various beta-lactamase-producing strains were studied and compared with those of cefotiam (CTM). CPZ had a broad spectrum against Gram-negative and Gram-positive bacteria. Especially, CPZ showed apparently more potent antibacterial activities than CTM against Enterobacter cloacae, Serratia marcescens, and Pseudomonas aeruginosa. However, CPZ was less active than CTM against Staphylococcus aureus and Proteus mirabilis. The stability and affinity of CPZ for various types of beta-lactamase were also studied. CPZ was more resistant to hydrolysis by typical cephalosporinase (CSase) and cefuroximase (CXase) than CTM, but was less stable to penicillinase (PCase). CPZ often showed higher affinity to beta-lactamases than CTM. The study for the inducer-activity revealed that CPZ hardly induced CSase production in E. cloacae and Proteus vulgaris while CTM highly induced in both strains. CPZ was more active against CSase-producers than CTM, especially against strains which inducibly produced the enzyme. It was speculated that this activity was responsible for the superior stability to CSase and low inducer-activity for CSase production.

The effect of M7310U, a new non-steroidal analgesic anti-inflammatory agent, on liver microsomal drug-metabolizing enzymes was investigated. Rats were treated orally with M73101 (100, 200, 500 mg/kg), henylbutazone (PZ, 200 mg/kg), aminopyrine (AM, 100 mg/kg) or phenobarbital sodium (PB, 100 mg/kg) once daily for 2 weeks and then were observed for 2 weeks during which treatment was not given. On treatment with M73101, PZ, AM and PB, the liver enlarged but was restored to normal 1 week after the last administration. The rate of increase in the case of M73101 was lower than that seen with the reference compounds. M73101 markedly increased the content of microsomal protein, cytochrome P-450 or b5 and NADPH cytochrome C reductase, aniline hydroxylase and AM demethylase activity, but these increments returned to the normal level 1 week after the last administration. The serum concentration of M73101 after repeated administration (200 mg/kg, p.o.) for 1 week was lower than that after a single administration. Furthermore, M73101 increased Vmax for both aniline hydroxylase and AM demethylase, whereas it increased Km only for aniline hydroxylase. M73101 did not enhance the lipid peroxidation. Our observations suggest that the enlargement of rat liver seen with M73101 was due to the induction of drug-metabolizing enzymes and that this agent can probably be classified as a phenobarbital-type inducer.

Kanechlor (KC)-300, 400, 500, and 600 consisting of polychlorinated biphenyls (PCB) containing 43, 48, 55, and 61% chlorine respectively, were administered in a single dose of 100 mg/kg to mice and rats. The effect of PCB was investigated by determining pentobarbital sleeping time, liver microsomal hemoprotein contents, PCB level and gaschromatography (GC) pattern in tissue. Pentobarbital sleeping time was prolonged 2 to 4 times longer than that of control level after 3 to 4 hr of KC treatment in both ICR and ddN strain mice and KC-300 was the most effective. Forty-eight hr after treatment, however, this sleeping time was half that of the control. Sleeping time in ICR strain mice returned to control level 8 days after the treatment with KC-300 and KC-500, but the decrease in sleeping time continued in ddN mice. Conversely, the prolongation of sleeping time in rats was only 20% the control level at 3 hr after KC-300 treatment, but the shortening of sleeping time was more marked than in mice. Both the prolongation of sleeping time in mice treated with KC-300 and the shortening of sleeping time in rats treated wiht KC-500 were more rapidly effected when an oral dose rather than when a intraperitoneal one was given. Induction of liver microsomal cytochrome P-450 level was maximum in rats treated with KC-600 and increase of hemoprotein level and shortening of sleeping time were proportional to the chlorine content of PCB. The CO-difference spectrum of microsomes from rats treated with KC had an absorbance maximum at 448 nm. Direct relationship between storage of PCB in adipose tissue and the induced effect by KC has also been demonstrated in rats. PCB level in the liver of rats was higher for about 8 hr after KC-500 treatment given orally and was lower than the PCB level in adipose tissue after 8 hr. The GC-pattern of PCB stored in tissues was different from that of standard KC, indicating that all components were not metabolized at the same rate and that the components of the KC with the longer retention time were metabolized to a lesser degree than those with the shorter retention time.