Protein deficiency and drug interactions: A Review

Combined effects of caffeine and malnutrition on the newborn rat's myocardium

We hypothesized that the pathological effects on the neonatal rat heart could be aggravated by Cu deficiency due to the combined effects of caffeine exposure and malnutrition. Upon birth, pups were mixed and randomly picked; 8 pups were assigned to each dam and then divided into 4 groups. Group 1 dams received a normal diet containing 20% protein. Group 2 dams were fed 20% protein diet supplemented with caffeine (4 mg/100 g BW). Group 3 dams received 6% protein diet as a malnourished group, and group 4 dams received 6% protein diet supplemented with caffeine (4 mg/100 g BW). On postnatal day 10, dams and pups were killed. Group 2 tended to have a decrease in the Cu levels of dams' plasma and milk and in pups' plasma and heart tissue compared to those of group 1. This pattern was not observed consistently between groups 3 and 4. Transmission electron microscopy of group 2 pups' hearts revealed a degree of disruption in the mitochondria compared to normal mitochondria seen in group 1. There was no consistent change in the mitochondria of group 4 compared to group 3. The caffeine level observed in all categories of group 4 (dams' plasma and milk, pups' plasma and heart tissue) was lower than those in group 2. Although malnutrition affected body weight and heart weight, combined effects of caffeine and malnutrition on Cu content in the neonatal heart was relatively minor compared to the well nourished group. This well nourished group showed that the effects of caffeine on Cu were more consistent, resulting the changes of mitochondria.

Combined effects of caffeine and malnutrition during pregnancy on suckling behavior in newborn rats

Six groups of pregnant dams were fed a 20%, 12%, and 6% protein diet with and without caffeine (2 mg/100 g b.wt.), starting on day 7 of gestation. At day 18 of gestation, randomly selected dams of each group were used to record prenatal fetal behavior. The remaining dams were continuously fed their respective diets until the birth of their pups. Upon delivery, newborn pups from the dams fed a 20%, 12%, or 6% protein diet with caffeine were placed with foster dams that the dietary regimen during gestation was a 20%, 12%, or 6% protein diet, respectively. Dams fed a noncaffeine diet, along with their newborns, were fed their respective diets until day 15. Suckling behavior tests for newborns were conducted on days 2, 8, and 15. On day 15, both nondeprived and deprived newborn rats were studied. Caffeine in combination with a malnourished diet has different effects on general activity in prenatal stages compared to postnatal stages. Our findings support the view that prenatal exposure to caffeine may produce greater effects because: a) caffeine and its metabolites pass freely into the embryo and attain a concentration slightly lower than in the maternal plasma; and b) caffeine may be poorly metabolized during pregnancy, causing an accumulation in the fetal tissues. Prenatal caffeine at the dosage we have used in combination with malnutrition may produce lasting metabolic alterations in the nervous system related to the emergence of suckling behavior and general motor activity.

Effects of caffeine on the DNA and protein synthesis of the protein-energy malnourished neonatal cardiac muscle cells in culture

1. The growth of cardiac cells derived from newborn rats whose dams were either malnourished or malnourished with caffeine during pregnancy was inhibited in culture over the period of 5 days as compared to that of the normally nourished cells. 2. Cells derived from malnourished rats with caffeine added to their diets showed a greater inhibition than those from the malnourished rats not given caffeine. 3. Both DNA and protein synthesis showed an inhibition due to caffeine in a dose-dependent manner using normally nourished cells. 4. In the presence of exogenous 2 mM caffeine, the degree of percent inhibition of DNA and protein synthesis of cells derived from rats malnourished with caffeine was less than that from the rats with malnutrition alone. 5. The present data indicated that malnutrition combined with caffeine during pregnancy exerted a greater negative effect on the nature of cell growth than malnutrition alone and these cells became less sensitive to exogenous caffeine.

The effects of age, sex and diet on the clastogenic action of cyclophosphamide in mouse bone marrow

7-week-old and 12-week-old mice of both sexes received either a control or protein-deficient diet for 3 weeks. Afterwards, they were given a single dose of cyclophosphamide (0.5 mg/10 g b.wt.) before being sacrificed. The relationship between age and the clastogenic action of cyclophosphamide can be observed in the bone marrow cells of male mice but not in those of female mice. 12-week-old males on a 75% protein-deficient diet have a lower frequency of cells with cyclophosphamide-induced chromosome aberrations than has the control group. On the contrary, 7-week-old males and females, and 12-week-old females, show that protein-deficient diets act synergistically with the clastogenic action of cyclophosphamide. These results are discussed taking the metabolism of the drug into account. Animal age also plays a role in the formation of chromosome rearrangements; this type of aberration is significantly more frequent in younger animals of both sexes than in older ones exposed to the drug.

Combined effects of moderate ethanol consumption and a low-protein diet during gestation on brain development in BALB/c mice

We investigated whether or not moderate ethanol consumption during gestation would interact with the effects of a low-protein diet in affecting brain development in BALB/c mice. The independent variables included fetal body and brain weights and cross-sectional area in midsagittal sections of the corpus callosum (CC) and anterior commissure (CA). Pregnant animals were fed either ethanol 12% v/v or an isocaloric sucrose solution from days 5 to 19 of gestation, when fetal development was assessed. In addition, the animals were fed semisynthetic isocaloric diets containing either 8 or 20% casein. All animals were pair-fed to those in the group receiving ethanol and 20% casein; an additional control group was fed lab chow ad libitum. There was clearly an interactive effect of diet and ethanol consumption on blood alcohol concentrations: those in the low-protein group were significantly higher than in the normal-protein group. Similarly, the effect on body weight in the group receiving low protein plus ethanol was greater than the additive effect of either treatment alone, although this may have been due partly to differences in litter size. Brain weight in this group was also significantly less than in the other three groups, which did not differ from each other. Covariance analysis, adjusting brain weight for body weight, suggested a brain-sparing effect of low protein but not ethanol. Neither treatment affected the incidence of the CC being absent at midline. The low-protein treatment decreased the cross-sectional area of both the CC and CA; the effect on the CC was independent of brain weight. There was no effect of ethanol on either of those measures.

Influence of age, sex, pregnancy and protein-calorie malnutrition on the pharmacokinetics of salicylate in rats

The influence of age, sex, pregnancy and protein-calorie malnutrition (PCM) on the plasma t1/2, plasma clearance (Clp) and apparent volume of distribution (Vd) of sodium salicylate (62 mumol kg-1) was determined in Sprague-Dawley rats. Female and male rats of five different age groups (ages in weeks: pups 1, weanling 3, young 8-9, adult including pregnant 14-15, old 56-60) including three age groups with PCM (8-9, 14-15 and 56-60 weeks old) were used. Plasma and urinary salicylates were assayed by h.p.l.c. Plasma t1/2 was longer and Clp smaller in pups than in weanling and young rats and comparable to values for old rats; Vd of salicylate in pups was larger than in any other group of rats. Plasma t1/2 was longer and Clp as well as Vd of salicylate were smaller in adult females than in males of comparable age. Relative to nonpregnant adult females, Vd of salicylate in pregnant rats was larger but plasma t1/2 and Clp were unchanged. In all groups of rats studied, PCM decreased the plasma t1/2 and increased the Clp of salicylate; Vd was unchanged. Changes in salicylate pharmacokinetics were not due to any differences in serum protein-salicylate binding or to serum testosterone levels. Ovariectomy decreased the plasma t1/2 of salicylate but castration of male rats had no significant effect. Administration of testosterone to ovariectomized female rats exerted no significant effect on salicylate pharmacokinetics. It is concluded that the physiological state and the nutritional status can modify salicylate pharmacokinetics; in so far as the rat model reflects the human situation, these variables should be taken into account for a rational salicylate therapy.

Infectious diseases and aging: immunologic perspectives

Four theories of aging provide a basis for understanding both the aging process and the primary alterations in host defenses that may occur with age. The immunologic theory of aging may be especially important in this regard, since immunologic defects may be responsible for many manifestations of aging, and a decline in immune function may also underlie the increased susceptibility of the aged to infection. However, multiple factors are probably responsible for the aging process and for changes in host defenses. Although several studies attempting to enhance the immune response of elderly persons and perhaps extend lifespan are in progress, no factor at present appears to be as important in this regard as three underutilized immunizations for influenza, pneumococcal infection, and tetanus.

Effect of pretreatment with sodium phenobarbital on the toxicity of soman in mice

Pretreatment with sodium phenobarbital induces hepatic microsomal enzymes which are responsible for the metabolic breakdown of a large number of endogenous and exogenous chemical compounds. A previous study [K. P. DuBois and F. K. Kinoshita, Proc. Soc. exp. Biol. Med. 129, 699 (1968)] reported that phenobarbital pretreatment reduced the toxicity of various organophosphorus anticholinesterases; however, the exact mechanism for the increased detoxification was not investigated. In this study, the effect of phenobarbital pretreatment on the toxicity of soman was investigated. Male mice were injected daily for 4 days with sodium phenobarbital (100 mg/kg, i.p.) and used in the various experiments 24 hr after the last injection. Phenobarbital pretreatment produced a significant increase in liver weight and decreased the sodium pentobarbital (75 mg/kg, i.p.) induced sleep-time to 41 min compared to 141 min in controls. The lethality of soman was reduced following phenobarbital pretreatment. In control mice, the soman 24 hr LD50 values (microgram/kg) were 130, 393 and 42 following s.c., i.p. and i.v. administration, respectively, whereas in phenobarbital-pretreated mice the soman 24 hr LD50 values (microgram/kg) were 261, 746 and 63 following s.c., i.p. and i.v. administration respectively. Acetylcholinesterase activity was increased in the plasma (90%) but not in brain or diaphragm following phenobarbital pretreatment. Liver somanase activity was not affected. Liver aliesterase and serum aliesterase were both increased significantly following phenobarbital pretreatment. An increase in the amount of nonspecific binding sites for soman (esterases in liver and plasma) and not an increase in the metabolism of soman in vivo probably accounts for the protection afforded by phenobarbital pretreatment in mice.

Drug-pyridoxal phosphate interactions

In this review it has been pointed out that vitamin B6 and its vitamers can be involved in many interactions with a number of drugs, as well as with the actions of various endocrines and neurotransmitters. Nutritional deficiencies, especially of vitamins and proteins, can affect the manner in which drugs undergo biotransformation, and thereby may also modify the therapeutic efficacy of certain drugs. The differences between nutritional vitamin B6 deficiency and the hereditary disorder producing pyridoxine dependency are discussed. In addition to a pyridoxine deficiency being able to adversely affect drug actions, the improper supplementation with vitamin B6 can in some instances also adversely affect drug efficacy. A decrease by pyridoxine in the efficacy of levodopa used in the treatment of Parkinsonism is an example. The interrelationships and enzymatic interconversions among pyridoxine vitamers, both phosphorylated and non-phosphorylated, are briefly discussed, particularly regarding their pharmacokinetic properties. The ways in which the normal biochemical functions of vitamin B6 may be interfered with by various drugs are reviewed. (1) The chronic administration of isoniazid for the prevention or treatment of tuberculosis can produce peripheral neuropathy which can be prevented by the concurrent administration of pyridoxine. An acute toxic overdose of isoniazid causes generalized convulsions, and the intravenous administration of pyridoxine hydrochloride will prevent or stop these seizures. (2) The acute ingestion of excessive monosodium glutamate will, in some individuals, cause a group of symptoms including among others headache, weakness, stiffness, and heartburn, collectively known as the 'Chinese Restaurant Syndrome.' These symptoms can be prevented by prior supplementation with vitamin B6. The beneficial effect is ascribed to the correction of a deficiency in the activity of glutamic oxaloacetic transaminase, an enzyme that is dependent on pyridoxal phosphate. Some interesting relationships are pointed out between vitamin B6, picolinic acid, and zinc. It is postulated that the intestinal absorption of zinc is facilitated by picolinic acid, a metabolite of tryptophan. The derivation of picolinic acid from tryptophan depends on the action of the enzyme kynureninase, which is dependent on pyridoxal phosphate; therefore, the adequate absorption of zinc is indirectly dependent on an adequate supply of vitamin B6. The formation of pyridoxal phosphate, on the other hand, appears to be indirectly dependent on Zn2++ which activates pyridoxal kinase.(ABSTRACT TRUNCATED AT 400 WORDS)