FEMALE ENDOCRINE CONTROL MECHANISMS DURING THE NEONATAL PERIOD

1972 ◽  
Vol 71 (3) ◽  
pp. 431-442 ◽  
Author(s):  
K.-D. Schulz ◽  
A. Harland ◽  
H. Haarmann
Keyword(s):  
Protein Synthesis ◽  
Guinea Pigs ◽  
Neonatal Period ◽  
Post Partum ◽  
Endocrine Function ◽  
Leucine Incorporation ◽  
Control Mechanisms ◽  
Endocrine Control ◽  
Rna And Protein Synthesis

ABSTRACT The present investigations deal with the in vivo effect of different doses of exogenous LH on the RNA- and protein-synthesis in the cerebral cortex, hypothalamus, pituitary, liver, ovary, uterus and adrenal gland of newborn guinea pigs. An increase of 3H-uridine and 3H-leucine incorporation was noted only in the ovary and the uterus. All the other organs showed no response. As early as 1 hour after the injection, LH induced a statistically significant stimulation of amino-acid incorporation into the proteins of the ovary. 2 hours later similar observations were made on the uterus reflecting an induction of uterotrophic steroid biosynthesis in the ovary in response to LH. The lowest effective dose was 5 IU LH/100 g body weight. Furthermore the experiments gave evidence for the dependence of oestrogen synthesis on the ovarian protein formation. The experimental data support the assumption that the ovary of newborn animals is not refractory to stimulation by gonadotrophic hormones. The ovary of newborn guinea pigs shows a relatively low sensitivity against RNA- and protein-synthesis inhibiting substances such as actinomycin and cycloheximide as compared to the liver. The mode of action of LH on the ovary seems to be identical during post partum life and advancing sexual maturation. The existing ovarian gonadotrophin sensitivity indicates that the hypothalamus or possibly the pituitary is primarily responsible for the functional immaturity of the endocrine ovarian control mechanisms during the neonatal period. The restricted functional capacity of the neonatal hypothalamus is characterized by the resistence of this organ to hormones regulating the hypothalamic endocrine function via short and long feedback mechanisms.

FEMALE ENDOCRINE CONTROL MECHANISMS DURING THE NEONATAL PERIOD

1973 ◽  
Vol 74 (1) ◽  
pp. 144-156 ◽  
Author(s):  
K.-D. Schulz ◽  
S. August
Keyword(s):  
Protein Synthesis ◽  
Adrenal Gland ◽  
Neonatal Period ◽  
Ovarian Response ◽  
Control Mechanisms ◽  
Endocrine Control ◽  
Rna And Protein Synthesis ◽  
Uterine Proteins ◽  
Cis And Trans

ABSTRACT The purpose of this paper is to report on the in vivo effect of different doses of cis- and trans-clomiphene on the RNA and protein synthesis in the ovary, liver, adrenal gland and uterus of newborn guinea pigs. After the sc injection of either isomer the biochemical parameters were determined at different time intervals. Both isomers induced an increase of the RNA- and protein-synthesizing activity in the uterus, but failed to do so in the ovary, liver and adrenal gland. According to data reported here and also by other investigators it may be assumed that the lack of ovarian response to the treatment with cis- or trans-clomiphene is primarily due to the functional immaturity of the female hypothalamus and/or pituitary during the neonatal period. Both isomers failed to modify the pattern of gonadotrophin release, as shown by the constancy of the ovarian RNA and protein synthesis after the administration of either of the isomers. In the uterus, both cis- and trans-clomiphene strikingly imitated the biochemical stimulation produced by natural oestrogens. In contrast to oestradiol-17β, both clomiphene isomers showed a later onset and longer duration of the oestrogenic activity. The first increase of the amino acid incorporation into uterine proteins was noted after 5 hours in the cis-clomiphene treated group and after 8 hours in the trans-clomiphene treated animals as compared to 1 hour when oestradiol-17β was used. This difference seems to be due to a delayed transfer of the cytoplasmic oestradiol receptor to the nucleus after the injection of cis- or trans-clomiphene. As compared to oestradiol-treated animals, the clomiphene injection provoked a prolonged elevation of the uterine protein-synthesizing activity, most likely reflecting an effect of the enterohepatic recirculation of both isomers.

FEMALE ENDOCRINE CONTROL MECHANISMS DURING THE NEONATAL PERIOD

1972 ◽  
Vol 70 (2) ◽  
pp. 396-408 ◽  
Author(s):  
K.-D. Schulz ◽  
H. Haarmann ◽  
A. Harland
Keyword(s):  
Protein Synthesis ◽  
Reproductive System ◽  
Rna Synthesis ◽  
Neonatal Period ◽  
High Dose ◽  
Female Reproductive System ◽  
Endocrine Control ◽  
Hypothalamic Region ◽  
Rna And Protein Synthesis ◽  
Physiological Dose

ABSTRACT The present investigation deals with the oestrogen-sensitivity of the female reproductive system during the neonatal period. Newborn female guinea pigs were used as test animals. At different times after a single subcutaneous injection of a physiological dose of 0.1 μg or an unphysiologically high dose of 10 μg 17β-oestradiol/100 g body weight, the RNA- and protein-synthesis was examined in the hypothalamic region, pituitary, cerebral cortex, liver, adrenal gland, ovary and uterus. With a physiological dose an increase in organ weight, protein content, RNA-and protein-synthesis was found only in the uterus. These alterations turned out to be dose-dependent. In addition to the findings in the uterus an inhibition of the aminoacid incorporation rate occurred in the liver following the injection of the high oestradiol dose. As early as 1 hour after the administration of 0.1 μg 17β-oestradiol an almost 100% increase in uterine protein synthesis was detectable. This result demonstrates a high oestrogen-sensitivity of this organ during the neonatal period. All the other organs of the female reproductive system such as the hypothalamus, pituitary and ovary did not show any oestrogen response. Therefore the functional immaturity of the uterus during post partem life is not the result of a deficient hormone sensitivity but is correlated with the absence of a sufficient hormonal stimulus at this time. The investigation on the effects of actinomycin resulted in different reactions in the uterus and liver. In contrast to the liver a paradoxical actinomycin effect was found in the uterus after treatment with actinomycin alone. This effect is characterized by a small inhibition of RNA-synthesis and a 50% increase in protein synthesis. The treatment of the newborn test animals with actinomycin and 17β-oestradiol together abolished the oestrogen-induced stimulation of the uterine RNA-and protein-synthesis. Consequently, the effect of oestrogens during the neonatal period is also connected with the formation of new proteins via an increased DNA-directed RNA-synthesis.

Use of an in Vitro Protein Synthesizing System to Test the Mode of Action of Chloracetamides

Weed Science ◽  
1980 ◽  
Vol 28 (3) ◽  
pp. 334-340 ◽  
Author(s):  
Luanne M. Deal ◽  
J. T. Reeves ◽  
B. A. Larkins ◽  
F. D. Hess
Keyword(s):  
Protein Synthesis ◽  
Sand Culture ◽  
Leucine Incorporation ◽  
Insoluble Protein ◽  
In Vitro System ◽  
A Cell ◽  
Protein Incorporation ◽  
Vitro Protein

The effects of chloracetamides on protein synthesis were studied both in vivo and in vitro. Four chloracetamide herbicides, alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide], metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide], CDAA (N–N-diallyl-2-chloroacetamide), and propachlor (2-chloro-N-isopropylacetanilide) were tested for inhibition of [3H]-leucine incorporation into protein. Incorporation of3H-leucine into trichloroacetic acid (TCA)-insoluble protein was inhibited in oat (Avena sativaL. ‘Victory’) seedlings grown in sand culture and treated 12 h at 1 × 10−4M with these chloracetamides. The herbicides were also tested in a cell-free protein synthesizing system containing polyribosomes purified from oat root cytoplasm. These herbicides had no effect on the rates of polypeptide elongation nor on the synthesis of specific polypeptides when herbicides (1 × 10−4M) were added directly to the system. Polypeptide formation was inhibited 89% when 1 × 10−4M cycloheximide was added during translation. Cytoplasmic polyribosomes were isolated from oat roots treated 12 h with 1 × 10−4M herbicide. Translation rates and products were not altered when these polyribosomes were added to the in vitro system. Protein synthesis is inhibited when tested in an in vivo system; however, the inhibition does not occur during the translation of mRNA into protein.

Polyglutamate Forms of Folate in Resting and Proliferating Mammalian Tissues

1975 ◽  
Vol 48 (1) ◽  
pp. 67-73 ◽  
Author(s):  
A. Lavoie ◽  
Edith Tripp ◽  
K. Parsa ◽  
A. V. Hoffbrand
Keyword(s):  
Protein Synthesis ◽  
Folic Acid ◽  
Partial Hepatectomy ◽  
Resting Cells ◽  
Mammalian Tissues ◽  
Pteroylglutamic Acid ◽  
Rna And Protein Synthesis ◽  
Blast Cells ◽  
Liver Folate

1. Tritiated folic acid (pteroylglutamic acid) was injected into rats whose livers were undergoing regeneration after partial hepatectomy, and into normal control rats. 2. The major form of labelled liver folate was found to be pteroylpentaglutamate in both hepatectomized and normal rats and there was no difference in the proportion of pteroylpentaglutamate to other forms of folate in the regenerating or resting liver. 3. Folate concentrations were also measured in leucocytes from normal and leukaemic patients. 4. Pteroylpolyglutamates constituted the main form of folate in both sets of cells. There was again no difference in proportion of pteroylpolyglutamate to pteroylmonoglutamate forms of folate between normal mature cells and primitive blast cells. 5. It is therefore suggested that pteroylpolyglutamates, which constitute nearly all the folates in cells actively synthesizing DNA and protein as well as in resting cells, probably act as the coenzymes in vivo for the folate-dependent reactions in DNA, RNA and protein synthesis in mammalian systems.

scholarly journals Synthesis of mitochondrial protein in the flight muscles of the Colorado beetle. Differentiation in vivo between extra- and intra-mitochondrial contributions to the amino acid incorporation into mitochondrial protein

1973 ◽  
Vol 136 (3) ◽  
pp. 795-802 ◽  
Author(s):  
A. K. M. Bartelink ◽  
C. A. D. De Kort
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Mitochondrial Protein ◽  
Leucine Incorporation ◽  
Amino Acid Incorporation ◽  
Linear Rate ◽  
Synthesis Conditions ◽  
Acid Incorporation ◽  
Flight Muscles

By using cycloheximide, an inhibitor of cytoplasmic protein synthesis, conditions were investigated to estimate in vivo the extra- and intra-mitochondrial contributions to the synthesis of organelle protein in the flight muscles of Colorado beetles. With 4-day-old beetles about 15% of the [14C]leucine incorporation into mitochondrial protein is resistant to the action of cycloheximide. The incorporation into cytosol protein is inhibited by more than 99.5% with cycloheximide. During the first hour after precursor administration the incorporation into mitochondrial protein proceeds, in both the presence and the absence of cycloheximide, at a more-or-less linear rate with time. The cycloheximide-resistant amino acid incorporation is sensitive to the inhibitor of mitochondrial protein synthesis, chloramphenicol. The uncertainties inherent in the use of cycloheximide were discussed in arriving at the conclusion that about 15% of the mitochondrial protein is formed inside the organelle.

scholarly journals Synthesis of proteins from [35S]methionine by guinea pig megakaryocytes in vivo and time course of appearance of newly synthesized proteins in platelets

Blood ◽  
1990 ◽  
Vol 76 (5) ◽  
pp. 887-891 ◽  
Author(s):  
BP Schick
Keyword(s):  
Protein Synthesis ◽  
Guinea Pigs ◽  
Time Course ◽  
Protein Pattern ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Molecular Weights ◽  
Sds Page ◽  
Relationship Of

The relationship of protein synthesis to megakaryocyte maturation has been studied in guinea pigs in vivo. Guinea pigs were injected with a single dose of [35S]methionine. Megakaryocytes and platelets were isolated daily for 4 days, and proteins from both cells were isolated by DEAE-Sephacel chromatography and analyzed by sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) and fluorography. All proteins in megakaryocytes corresponding to stained bands on the SDS- PAGE gels were radiolabeled at 3 hours after injection. The greatest loss of radioactivity from the megakaryocytes occurred between 1 and 3 days after injection. Only trace labeling of platelet proteins was seen at 3 hours, representing almost entirely three bands at molecular weights 47,000, 52,000, and 66,000. At 24 hours only about 13% of the maximal labeling was present, but not all proteins were labeled. The maximal labeling was at 3 days. The pattern of labeling of platelets at 3 days was identical to that of megakaryocytes at 3 hours. The protein pattern of nonmegakaryocytic marrow cells was different from that of the platelets and megakaryocytes. Data presented here suggest that most protein synthesis in megakaryocytes is completed at least 24 hours before release of the platelets to the circulation, and suggest some specificity in the proteins that are synthesized at the terminal stages of maturation.

THYROXINE STIMULATION OF AMINO ACID INCORPORATION INTO MITOCHONDRIAL PROTEIN: DIFFERENCES BETWEEN IN VIVO AND IN VITRO EFFECTS

1973 ◽  
Vol 72 (4) ◽  
pp. 684-696 ◽  
Author(s):  
Amirav Gordon ◽  
Martin I. Surks ◽  
Jack H. Oppenheimer
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Mitochondrial Protein ◽  
Leucine Incorporation ◽  
Mitochondrial Protein Synthesis ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Stimulation Of

ABSTRACT The in vivo and in vitro stimulation of rat hepatic mitochondrial protein synthesis by thyroxine (T4) was compared. In confirmation of Buchanan & Tapley (1966). T4 added to isolated mitochondria rapidly stimulated [14C] leucine incorporation into mitochondrial protein. The in vitro stimulation was reversed after T4 was removed by incubating the mitochondria with bovine serum albumin (BSA). The decrease in T4 stimulation of protein synthesis appeared proportional to the T4 removed by BSA. Thus, it appears probable that exchangeable T4 controls the in vitro system. In contrast, the increase in mitochondrial protein synthesis which was observed 3 to 4 days after pretreatment of hypothyroid rats with labelled and non-radioactive T4 was not reversed by BSA treatment. Moreover, mitochondrial radioactivity could not be extracted with albumin. The in vivo phenomenon does not, therefore, appear to be related to exchangeable hormone in the mitochondria. Furthermore, the estimated quantity of T4 associated with mitochondria after in vivo stimulation was at least two orders of magnitude less than that required to produce comparable stimulation of mitochondrial protein synthesis in vitro. These findings strongly suggest that in vitro and in vivo stimulation of amino acid incorporation by T4 may be mediated by different biochemical mechanisms.

HORMONAL REGULATION OF RNA AND PROTEIN SYNTHESIS IN THE MOUSE MAMMARY GLAND BEFORE AND DURING LACTATION

1971 ◽  
Vol 50 (2) ◽  
pp. 281-291 ◽  
Author(s):  
M. R. BANERJEE ◽  
FERNE M. ROGERS ◽  
D. N. BANERJEE
Keyword(s):  
Protein Synthesis ◽  
Mammary Gland ◽  
Hormonal Regulation ◽  
Rna Synthesis ◽  
Mouse Mammary Gland ◽  
Synthetic Activity ◽  
Tissue Homogenate ◽  
Mammary Tissue ◽  
Leucine Incorporation

SUMMARY As measured by [3H]uridine incorporation in vivo, the low rate of RNA synthesis in the mammary gland of virgin C3H and BALB/c mice increased sixfold in the mammary tissue of 15-day pregnant mice. In the 5-day lactating gland, RNA synthesis was ten times higher than that in virgin mammary tissue. On the 10th day of lactation this increased RNA synthetic activity in the mammary gland was considerably reduced but was still twice that of the mammary tissue of virgin mice. Twenty-four hours after adrenalectomy, RNA synthesis in lactating glands was reduced by over 80%, whereas in the mammary gland before lactation, it was reduced by 20–30% only. A single i.p. injection of 250 μg of cortisol led to a threefold increase of RNA synthesis within 1 to 2 h in lactating glands of adrenalectomized mice; this was followed by a decline. Incorporation of [3H]leucine into trichloroacetic acid-insoluble material from lactating mammary tissue was used as a measure of'total protein' synthesis, and [3H]leucine radioactivity determined in Ca2+−rennin precipitate of 105000 g supernatant of lactating mammary tissue homogenate was used as a measure of casein synthesis. Adrenalectomy caused a 50% reduction of 'total protein' synthesis, whereas synthesis of 'casein-like' phosphoprotein virtually stopped after the operation. The injection of cortisol into adrenalectomized mice induced a selective increase of [3H]leucine incorporation into the casein of lactating glands. The results indicate that RNA synthesis in the mammary tissue is more dependent on adrenal hormones during the functional than the structural state of differentiation. The hormonal regulation of RNA synthesis and its role in milk protein synthesis in the mammary gland in vivo is discussed.

scholarly journals A possible mechanism of inhibition of protein synthesis by dimethylnitrosamine

1967 ◽  
Vol 105 (2) ◽  
pp. 625-631 ◽  
Author(s):  
S. Villa-Treviño
Keyword(s):  
Protein Synthesis ◽  
Messenger Rna ◽  
Transfer Rna ◽  
The State ◽  
Leucine Incorporation ◽  
Mechanism Of Inhibition ◽  
Nuclear Rna ◽  
Inhibition Of Protein Synthesis ◽  
Hepatic Protein Synthesis

1. The incorporation of [14C]leucine into liver proteins of rats was measured in vivo at various times after treatment of the animals with dimethylnitrosamine and was correlated with the state of the liver ribosomal aggregates. Inhibition of incorporation ran parallel with breakdown of the aggregates. 2. Inhibition of leucine incorporation into protein and breakdown of ribosomal aggregates were not preceded by inhibition of incorporation of [14C]orotate into nuclear RNA of the liver. 3. Evidence was obtained of methylation of nuclear RNA in the livers of rats treated with [14C]dimethylnitrosamine. 4. Zonal centrifugation analysis of radioactive, nuclear, ribosomal and transfer RNA from livers of rats treated with [14C]dimethylnitrosamine revealed labelling of all centrifugal fractions to about the same extent. 5. It is suggested that methylation of messenger RNA might occur in the livers of dimethylnitrosamine-treated rats and the possible relation of this to inhibition of hepatic protein synthesis is discussed.

Effect of acute food restriction on pulmonary growth and protein turnover in preterm guinea pigs

1992 ◽  
Vol 262 (2) ◽  
pp. E240-E245
Author(s):  
F. J. Kelly ◽  
J. C. Fussell ◽  
T. D. Postle
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Guinea Pigs ◽  
Food Restriction ◽  
Chain Elongation ◽  
Free Access ◽  
Repair Capacity ◽  
Reduced Body ◽  
Immature Lung

The effects of food restriction on the growth and protein turnover of the immature lung were investigated. Preterm guinea pigs, delivered by cesarean section at 65 days gestation (term = 68 days), were given free access to a lactating dam or restricted from feeding for 48 h. Food restriction resulted in significantly reduced body and lung (P less than 0.05) weight compared with fed controls. The rate of pulmonary protein synthesis determined in vivo was reduced by 33% in the food-restricted pups (28.9 +/- 10.2 vs. 19.4 +/- 4.5%, P less than 0.05 for control and food-restricted pups, respectively), whereas the calculated rate of protein breakdown remained unchanged. The inhibition of protein synthesis was accounted for by a 36% decrease in ribosomal efficiency (11.03 +/- 2.61 vs. 7.04 +/- 1.26%, P less than 0.01 for control and food-restricted pups, respectively), whereas ribosomal capacity was unaltered. Polyribosomal analysis indicated an increase in the proportion of RNA present in polysomes and a fall in the free monomer pool (26%), suggesting that food restriction blocked translation by reducing the rate of peptide chain elongation. This finding was confirmed by the analysis of ribosome transit times, which indicated a significant increase in the elongation rate in the lungs from food-restricted pups (0.51 +/- 0.11 vs. 0.94 +/- 0.19 min, P less than 0.05 for control and food-restricted pups, respectively). These results imply that nutrient supply plays an important role in protein deposition and hence growth and repair capacity of the immature lung.

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