Lithium and twenty-four hour rhythms of serum corticosterone, prolactin and growth hormone in pigmented eye rats

Lithium, a widely used substance for the treatment of manic-depressive illness, has been reported to alter the phase relationships of a variety of biological rhythms. We have previously found that lithium affects serum melatonin differently in albino compared to pigmented eye rats. The present study was undertaken to investigate the effect of lithium on pituitary rhythms in pigmented eye rats. Six point 24 hour maps were generated throughout a 12 hour light/12 hour dark lighting regime on separate groups of individually housed adult male Long Evans rats (with pigmented eyes), maintained for six weeks on ad lib water and either normal lab chow or lab chow supplemented with 50 mM/Kg of lithium chloride. Animals were sacrificed by rapid decapitation with care to ensure that blood samples were obtained from subjects in the resting, undisturbed state. Plasma lithium levels were 0.57 +/- 0.02 mEq/1. In comparison to normal controls, lithium treatment suppressed body weight by 19%, and increased water intake by 100%. Absolute corticosterone levels were not altered by lithium, but the 24-hour pattern was significantly changed. Growth hormone levels were significantly reduced by lithium treatment without alteration of the 24-hour pattern. Prolactin levels were significantly reduced by lithium and the normal 24-hour variation was attenuated. Comparison of these effects of lithium in pigmented eye rats with similar data from albino rats suggests that the effects on growth hormone, body weight and water intake were similar; however, the effects on prolactin and corticosterone differed.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of single oral dose administration of a hydantoin prostaglandin analogue BW 245C in man

Following an open pilot study, BW 245C , a hydantoin prostaglandin analogue, was given by mouth in an aqueous solution to six healthy volunteers. The subjects received BW 245C 50 and 150 micrograms and placebo on separate occasions according to a double blind randomised design. Heart rate, blood pressure and, using visual analogue scales, facial flushing, abdominal discomfort and headache, were measured before dosing, at 15 minute intervals after dosing for 2 hours and at 30 minute intervals for a further 2 hours. Platelet aggregation responses to ADP and to collagen were measured before dosing and at 15 minutes, 45 minutes, 2 hours and 4 hours after dosing. Cutaneous bleeding time was measured before and 45 minutes after dosing. 150 micrograms BW 245C produced significant (p less than 0.05) facial flushing over the period from 15 to 120 minutes after dosing. Heart rate increased slightly but significantly (p less than 0.05) in response to both doses of 245C only at 75 minutes after dosing. Systolic and diastolic blood pressures were unchanged by either dose of BW 245C . Platelet aggregation responses to ADP were significantly (p less than 0.05) inhibited only at 120 minutes after 150 micrograms BW 245C . Aggregation responses to collagen were significantly (p less than 0.05) inhibited 45 and 120 minutes after 150 micrograms BW 245C and also at 120 minutes after 50 micrograms BW 245C . Bleeding time was unchanged in response to either dose of BW 245C . There was no change in headache or abdominal discomfort scores following either dose of BW 245C . Nausea was reported after 7 out of 12 administrations of BW245C but not after placebo. Nasal congestion was experienced by two subjects receiving 150 micrograms BW 245C and muscle tension and stiffness, especially of the jaw muscles, was also reported following administration of BW 245C but not of placebo. BW 245C is active when given by mouth and has similar pharmacodynamic effects to prostacyclin in man.

Lithium in pigmented eye rats: effects of dose and time of day on drinking, body weight, retinal and blood distribution

Lithium has been implicated in chronobiology (Seggie, et al., 1982, 1983). Previous work was done in Wistar rats, an Albino species, which lack the enzyme for synthesis of eye pigment. This pigment is important in regulation of light cued rhythms. The present project extends observations to Long Evans rats, a strain which has a pigmented eye. Groups of adult male rats were fed one of three diets: (1) normal laboratory chow; (2) a low lithium diet: lab chow supplemented with 30 mM/kg lithium chloride; and (3) a high lithium diet: lab chow supplemented with 50 mM/kg lithium chloride. Adult male rats were house individually with free access to diet and water under a 12 hour light/12 hour dark schedule. After six weeks on the diets, body weight, water intake, plasma, red blood cell and retinal lithium and retinal weight were measured every 4 hours throughout the 24 hour cycle following sacrifice by rapid decapitation. Plasma lithium levels on the high diet were 0.57 +/- 0.02 mEq/l and did not evidence a diurnal rhythm. Plasma lithium levels on the low diet were 0.35 +/- 0.01 mEq/l and evidenced a small, but significant diurnal rhythm with levels lowest just before darkness and normal food intake. Red blood cell lithium levels were significantly higher than plasma levels at 0.83 +/- 0.02 and 0.52 +/- 0.02 mEq/l for the high and low diets. Low diet, but not high diet red blood cells lithium levels evidenced a significant rhythm with a pattern similar to that seen in plasma lithium levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Lithium and melatonin in pigmented eye rats: effects of dose and time of day

Lithium has been suggested to exert some of its theraputic effects by modifying the function of the retinal-hypothalamic pineal pathway that is essential for the chronobiology of an organism (Seggie et al., 1983). Previous work was done in Wistar rats, an Albino species which lacks the enzyme for synthesis of eye pigment. This pigment is important in the regulation of light cued rhythms. The present project investigated effects of lithium in a pigmented eye strain. Adult male Long Evans rats were maintained individually on a 12 hour light/12 hour dark schedule with free access to water and one of three diets: (1) normal laboratory chow; (2) a low lithium diet: lab chow supplemented with 50 mM/kg of lithium chloride. Body weight and water intake were measured after six weeks on the diets. In Experiment I, separate groups of rats were sacrificed by rapid decapitation every 4 hours in the light/dark cycle. In Experiment II, animals were sacrificed every 90 min. between 12:00 and 20:00 hours during the dark cycle. Blood and pineal glands were collected for lithium determination and assay of melatonin by RIA. In Experiment I, plasma lithium levels were 0.35 +/- 0.01 and 0.57 +/- 0.02 mEq/1 for the low and high diets. Serum and pineal melatonin evidenced the expected diurnal rhythms. The diets had no effect on these parameters except at 14:00 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of cytochalasin H on the embryonic endodermal cells of Microhyla ornata

Cytochalasin H (CH) like CB causes disaggregation of embryonic endodermal cells and reduces their adhesivity to the glass surface. These cells reaggregate on removal of the drug from the medium. Reversibility depends on the duration of drug treatment. The mechanism of drug action is explained.