Biomedical subjects

K Bauer

Publications and source records attributed to K Bauer.

At least 73 records · Page 4Linked to original sources

PubMed1998

Postnatal body weight curves for infants below 1000 g birth weight receiving early enteral and parenteral nutrition.

UNLABELLED: No body weight curves are available for preterm infants < 1000 g birth weight receiving early enteral and parenteral nutrition. Postnatal weight changes of 136 infants with a birth weight < 1000 g were analysed retrospectively. Body weight curves for the first 30 days of life were generated for five separate birth weight groups (430-599 g, 600-699 g, 700-799 g, 800-899 g, 900-999 g). All infants had received intravenous glucose and amino acids from day 1 and intravenous lipids from day 2. Enteral feeding was started on day 1. Thus caloric intake (+/-SD) was advanced to 384+/-46 kJ/kg per day (92+/-11 kcal/kg/day) in the 1st week of life. In 136 preterm infants mean postnatal weight loss was 10.1%+/-4.6% of birth weight, birth weight was regained at a mean postnatal age of 11+/-3.7 days, but significantly earlier (7.8+/-3.5 days) in the lowest compared to the highest weight group. Mean subsequent weight gain was 15.7+/-7.2 g/ kg per day. This was accomplished by exclusive enteral nutrition from day 20 (median). CONCLUSION: Our body weight curves are more adequate to evaluate growth of preterm infants than older published reference values because they are based on infants treated according to current nutritional standards.

Enteral Nutrition↗

PubMed1998

Critical thinking's role in perioperative patient safety outcomes.

Despite education, training, tools, and standards, patient safety issues continue to be of concern when it comes to perioperative care. The problem of intraoperative injuries, therefore, may lie in perioperative nurses' implementation of safety measures that require critical thinking. This qualitative study lends insight into the critical thinking or decision-making processes of nurses who implement these perioperative safety measures. Findings from this data analysis have led to perioperative recommendations that may enhance patient safety outcomes.

Humans↗

PubMed1998

Region-specific expression of thyrotrophin-releasing hormone-degrading ectoenzyme in the rat central nervous system and pituitary gland.

Thyrotrophin-releasing hormone (TRH), a hypothalamic neuropeptide hormone and a putative neuromodulator/ neurotransmitter in the central nervous system is inactivated by the TRH-degrading ectoenzyme (TRH-DE), a TRH-specific metallopeptidase localized on the surface of neuronal brain cells in culture and on lactotrophic cells of the pituitary. After succeeding in cloning the cDNA of TRH-DE we now report on the cellular distribution pattern of this enzyme in rat brain, spinal cord and pituitary gland using in situ hybridization histochemistry. In the pituitary, TRH-DE mRNA was found both in the anterior and the neural lobe but not in the intermediate lobe. After treatment with triiodothyronine (T3) a dramatic increase in the mRNA levels of the TRH-DE and a decrease in the intensity of the TRH receptor could be observed in the anterior lobe of the pituitary. In brain, TRH-DE transcripts were predominantly found in neo- and allocortical regions with strongest signals in the olfactory bulb, the piriform cortex, the cerebral cortex, the granular layer of the cerebellar cortex and the pyramidal cells of the Ammon's horn. In the diencephalon, the highest TRH-DE mRNA levels were observed in the medial habenulae followed by several hypothalamic subregions. In the mesencephalon and brainstem, moderate signals were present in the superior colliculi, substantia nigra, dorsal raphe and in the periolivar region. In the spinal cord, TRH-DE mRNA positive neurons were present in all layers. The very distinct distribution of TRH-DE in the brain and the hormonal regulation of the adenohypophyseal enzyme support the concept that this peptidase serves very specialized functions.

Aminopeptidases↗

PubMed1998

The thyrotropin-releasing hormone-degrading ectoenzyme: the third element of the thyrotropin-releasing hormone-signaling system.

The peptidergic signal substance thyrotropin-releasing hormone (TRH) is inactivated by the TRH-degrading ectoenzyme (TRH-DE), a peptidase that exhibits an extraordinary high degree of substrate specificity and other unusual characteristics. There is no other ectopeptidase known capable of degrading this tripeptideamide, and vice versa, TRH is the only known substrate of this unique enzyme. Thus, studies on this enzyme may reveal new aspects on the function of the TRH signaling system. After succeeding in purifying this enzyme to homogeneity and cloning the cDNA encoding rat TRH-DE, molecular tools became available to study the expression of this enzyme by Northern blot analysis and in situ hybridization histochemistry. The stringent and tissue-specific regulation of the adenohypophyseal TRH-DE by estradiol and thyroid hormones strongly suggests that this enzyme may act as a regulatory element modulating pituitary hormone secretion. In brain, the expression of TRH-DE is not influenced by peripheral hormones but the distinct distribution pattern, and the high activities support the concept that in this tissue TRH-DE may act as a terminator of TRH signals.

Aminopeptidases↗

PubMed1998

Immunogenetic evidence for the phylogenetic sister group relationship of dogs and bears (Mammalia, Carnivora: Canidae and Crsidae). a comparative determinant analysis of carnivoran albumin, c3 complement and immunoglobulin micro-chain.

Thirty-seven antigenic determinants were identified in the albumins, the immunoglobulin micro- and IgG(Fc) chains, and the C3 proteins of 51 carnivoran (sub)species from 31 genera, and in 12 noncarnivoran mammals. In addition to 19 determinants plesiomorphic for Carnivora as an order, 18 synapomorphic epitopes of carnivoran families revealed nine phylogenetic reaction groups: (1) canids, (2) ursids, (3) the racoon, (4) the Weddell seal, (5) the lesser panda, (6) the harbour seal, (7) mustelids, (8) viverrids and hyaenas, and (9) felids. These data identify Canoidea (Canidae, Ursidae, Phocidae, Procyonidae, Ailuridae, Mustelidae) and Feloidea (Viverridae, Hyaenidae, Felidae) as two fundamentally differentiated lineages of Carnivora, and confirm the inclusion of seals among the former. The Ursidae are the sister group of the Canidae. The antigenic determinants in the studied proteins do not subdivide the Canidae, Ursidae and Felidae into immunologically differentiated lineages.

Albumins↗

PubMed1998

Effects of gestational and postnatal age on body temperature, oxygen consumption, and activity during early skin-to-skin contact between preterm infants of 25-30-week gestation and their mothers.

Temporary skin-to-skin contact between preterm infant and the mother is increasingly used in neonatal medicine to promote bonding. It is not known at which gestational age (GA) and postnatal age skin-to-skin contact outside the incubator is a sufficiently warm environment and is tolerated by preterm infants without a decrease in body temperature, oxygen consumption (VO2) increase, or unrest. We conducted a prospective clinical study of 27 spontaneously breathing preterm infants of 25-30-wk GA. Rectal temperature (Trecta), VO2 (indirect calorimetry), and activity were continuously measured in the incubator (60 min), during skin-to-skin contact (60 min), and back in the incubator (60 min) in wk 1 and 2 of life. In wk 1 the change in Trectal during skin-to-skin contact was related to GA (r=0.585, p=0.0027): infants of 25-27-wk GA lost heat during skin-to-skin contact, whereas infants of 28-30 wk gained heat and their mean Trectal during skin-to-skin contact was 0.3 degrees C higher than before (p < 0.01). No significant changes of VO2 or activity occurred. In wk 2 the infants' VO2 was higher than in wk 1, but VO2 during skin-to-skin contact was the same as in the incubator. Only small fluctuations in Trectal occurred. In wk 2 all infants slept more during skin-to-skin contact than in the incubator (p < 0.02). We conclude that, for preterm infants of 28-30-wk GA, skin-to-skin contact was a sufficiently warm environment as early as postnatal wk 1. For infants of 25-27-wk GA skin-to-skin contact should be postponed until wk 2 of life, when their body temperature remains stable and they are more quiet during skin-to-skin contact than in the incubator.

Adult↗

PubMed1998

Diagnostic challenges of hepatitis C virus infections.

In less than 10 years, tremendous progress has been made in our understanding of the biology of hepatitis C virus. Since it was defined as the causal agent of most hepatitis non-A, non-B infections in 1989, clinical laboratories now have access to powerful new techniques for the diagnosis of infection and control of therapy. Identification of the specific virus strain in the patients as well as measurement of the individual viral load and the prediction of a possible therapeutic success have become routine procedures. This effort is warranted because the treatment options are still limited, with alpha-interferon being the only approved drug. No new treatment regimens have emerged yet from the wealth of data from subtyping and quantitating.

Journal Article↗

PubMed1998

Restriction digest PCR (RD-PCR) for the analysis of gene mutations. Application to Ki-ras.

The Kirsten-ras (onco)gene codes for a GTP-binding membrane protein that is involved in signal transduction. Activated ras triggers a cascade of protein-phosphorylations that ultimately lead to cell proliferation. Ras-mutations are the main cause for adenocarcinomas of the pancreas besides some mutations in the tumor suppressor gene p53 and the c-erbB-2 oncogene. The site of ras mutations in pancreatic cancer is restricted to codon 12 that normally encodes a glycine. For analysis of codon-12 mutations, DNA is extracted from cells in pancreatic fluid and amplified by PCR. Because most of these cells originate from normal tissue with only a few tumor cells in the fluid, "enrichment PCR" must be utilized: In a first round of the PCR, ras sequences from all cells are amplified. By utilizing an appropriate restriction enzyme, wild-type sequences can be digested and the remaining fragments containing mutated sequences be amplified again. An artificial restriction site must be introduced by the 5'primer (...GGA CCT GGT...) for an enzyme (BstNI) (5'CC!WGG 3') to differentiate between wild-type sequence (...GGA GCT GGT...) (during amplification, the G is replaced by a C) and mutated sequences (_...GGA GCT (GTT), (CGT), (CCT), etc.). The necessary manipulations pose a considerable risk for contamination for the second round of the PCR procedure. Therefore, we considered whether it would be feasible to perform the restriction digest simultaneously with the first PCR reaction, and avoiding the second round altogether. The results of our experiments demonstrate that one tumor cell in 1000 normal cells can be determined readily, paralleling the results with the original two step-assay. The restriction enzyme used to enrich mutated sequences is stable long enough to be included into the PCR procedure. By this, wild-type sequence amplicons are digested while they are formed and mutated sequences can be enriched selectively.

Base Sequence↗

PubMed1997

Foot- and-mouth disease as zoonosis.

Man's susceptibility to the virus of foot- and-mouth disease (FMD) was debated for many years. Today the virus has been isolated and typed (type O, followed by type C and rarely A) in more than 40 human cases. So no doubt remains that FMD is a zoonosis. Considering the high incidence of the disease (in animals) in the past and in some areas up to date, occurrence in man is quite rare. In the past when FMD was endemic in Central Europe many cases of diseases in man showing vesicles in the mouth or on the hands and feet were called FMD. The first suggestion of a human infection with FMD was reported in 1695 by Valentini in Germany [7]. All reports before 1897, the year of the discovery of the virus of FMD by Loeffler and Frosch [2], were not of course confirmed either by isolation of the virus or by identification of immunoglobulins after infection. Nevertheless the successful self-infection reported by Hertwig in 1834 most likely seems to have been FMD in man: each of three veterinarians drank 250 ml of milk from infected cows on four consecutive days. The three men developed clinical manifestations. The diseases most often confused with FMD are infections with several viruses of the Coxsackie A group (this infection is referred to as "hand and mouth disease"), herpes simplex and sometimes vesicular stomatitis. Beginning in 1921 up to 1969 at least 38 papers were published, which described clinically manifest FMD in man in more than 40 proven cases. One further reported described an asymptomatic infection with FMD in man [10]. Criteria for establishing a diagnosis of FMD in man are the isolation of the virus from the patient and/or identification of specific antibodies after infection. Laboratory tests for diagnosis of human FMD are the same as for animals. Proven cases of FMD in man have occurred in several countries in Europe, Africa and South America. The type of virus most frequently isolated man is type O followed by type C and rarely A. The incubation period in man, although somewhat variable, has not been found to be less than two days and rarely more than six days.

Animals↗

PubMed1997

Serum levels of soluble CD44 variant isoforms are elevated in rheumatoid arthritis.

Serum levels of soluble CD44 variant proteins including sequences encoded by exon v5 and exon v6 (sCD44v5, sCD44v6) were determined in patients with inflammatory rheumatic diseases: 56 with rheumatoid arthritis (RA+) and 31 with miscellaneous inflammatory rheumatic diseases (MIRD). There were very significantly higher serum levels of sCD44v5 and sCD44v6 in patients with RA+ than in those with MIRD (RA+ to MIRD: sCD44v5: 81 +/- 54 ng/ml to 33 +/- 13 ng/ml; sCD44v6: 237 +/- 124 ng/ml to 166 +/- 53 ng/ml; both P << 0.001). In RA+ elevated serum levels of sCD44v5 were correlated with the inflammatory activity of disease. In 17 patients with RA+ three or four follow-up measurements of sCD44v5 were performed within 6 months. The development of sCD44v5 serum levels reflected the clinical course of disease in the patients investigated.

Adult↗

PubMed1997

Correction factors of 3H-beta-self-absorption for quantitative autoradiography of different cell types in the brain of pre- and postnatal mice.

Interferometric and morphometric studies were performed on seven types of brain cells of deparaffinised and Feulgen-stained brain sections of pre- and postnatal mice in order to find out to what extent 3H-beta-self-absorption factors (c.f.s) of karyoplasm and perikaryal cytoplasm change as the animals' age increases. This is important when comparing grain numbers of different cell types among mice of different age in quantitative autoradiographic studies after application of tritium-labelled substances. While optical path differences (o.p.d.s) of euchromatin and cytoplasm decreased in large neurons postnatally, heterochromatic o.p.d.s remained more or less unchanged. The fraction of euchromatin (fEu) and heterochromatin (fHe) changed specifically in relation to cell type with increasing age, i.e. mostly heterochromatin increased postnatally. Within a given age, c.f.s, calculated from o.p.d.s, fEu and fHe, varied up to a maximum factor of 2.16 for karyoplasm and a factor of 1.19 for cytoplasm between different cell types. A significant decrease of c.f.s postnatally was found only for the cytoplasm of cortical and hippocampal pyramidal cells and for cerebellar Purkinje cells. The c.f.s of karyoplasm remained more or less unchanged with increasing age of the mice. The calculation of relative c.f.s makes these c.f.s applicable for every other autoradiographic study using 3H-labelled substances.

Animals↗

PubMed1997

Body temperatures and oxygen consumption during skin-to-skin (kangaroo) care in stable preterm infants weighing less than 1500 grams.

BACKGROUND: More and progressively smaller preterm infants are taken out of the incubator and placed skin to skin on their mother's chest to promote bonding, despite concerns that the infants are exposed to cold during this intervention. OBJECTIVE: To test the hypothesis that skin-to-skin care is a cold stress for preterm infants weighing less than 1500 gm, with a decrease in rectal temperature, a decrease in peripheral skin temperature, or an increase in oxygen consumption compared with conditions monitored during incubator care. STUDY DESIGN: We studied 22 stable, spontaneously breathing preterm infants weighing less than 1500 gm (appropriate in size for gestational age), who had their first skin-to-skin care in the first week of life. We continuously measured rectal temperature, peripheral skin temperature (foot), and oxygen consumption (indirect calorimetry) for 1 hour in a thermoneutral incubator, during 1 hour of skin-to-skin care, and for another hour in the incubator. Mean values for the three periods were compared by analysis of variance. RESULTS: During skin-to-skin care the mean rectal temperature was 0.2 degree C (p < 0.01) and the peripheral skin temperature was 0.6 degree C (p < 0.01) higher than during the preceding hour in the incubator. Back in the incubator, body temperatures returned to values recorded before skin-to-skin care. Oxygen consumption during skin-to-skin care (6.1 +/- 0.9 ml/kg per minute) was not significantly higher than in the incubator (5.8 +/- 0.8 ml/kg per minute). CONCLUSION: For stable preterm infants weighing less than 1500 gm and less than 1 week of age, 1 hour of skin-to-skin care is not a cold stress compared with care in a thermoneutral incubator.

Body Temperature↗

PubMed1997

Comparison of face mask, head hood, and canopy for breath sampling in flow-through indirect calorimetry to measure oxygen consumption and carbon dioxide production of preterm infants < 1500 grams.

Complete sampling of expired air is essential for accurate O2 consumption(CO2 production) [VO2(VCO2)] measurements with flow-through indirect calorimetry. In preterm infants complete sampling is critical, because only low sampling flows can be used. The accuracy of the various breath sampling systems at low flows and their patient compatibility is untested. We therefore measured 1) the accuracy of VO2(VCO2) measurements with a face mask, a head hood, and a canopy in vitro at low sampling flows; 2) the effect of breathing on measurements with the face mask; and 3) the effect of breath sampling systems on activity and body temperature of preterm infants. VO2(VCO2) were measured with a Deltatrac II. In vitro we used a methanol miniburner incorporated into a doll, which could simulate low VO2(VCO2) and tidal breathing. In vivo we studied seven preterm infants < 1500 g. With the face mask VO2(VCO2) measurements were accurate at a flow of 3 L/min (error -1 +/- 0.8%), when tidal volume was < 15 mL/breath and the distance between mask and manikin < 1 cm. With hood and canopy VO2(VCO2) were underestimated at a flow of 3 L/min (error -13 +/- 1% and -14 +/- 5%), and results were markedly influenced by body position. For accurate measurements, the hood needed a flow of 4.5 L/min, the canopy 8.3 L/min. In vivo the face mask did not increase heart rate, respiration, activity, or rectal temperature, but hood and canopy increased rectal temperature by 0.3-0.4 degree C. For VO2(VCO2) measurements in infants < 1500 g, a face mask should be used, which is accurate at low flows and does not change body temperature. Accuracy at low flows and patient compatibility of breath sampling systems should be evaluated and reported for VO2(VCO2) measurements in preterm infants.

Body Temperature↗

PubMed1997

Thyrotropin-releasing hormone gene expression by anterior pituitary cells in long-term cultures is influenced by the culture conditions and cell-to-cell interactions.

It has been suggested that TRH, synthesized by anterior pituitary (AP) cells in long-term monolayer cultures, may act as a paracrine or autocrine regulator. Because local control through messenger molecules depends on the cellular microenvironment, we were interested in studying the synthesis of TRH by AP cells in different culture systems and under various conditions. When AP cells were cultured as monolayers in medium containing 10% FCS for long periods of time (up to 3 weeks), a considerable increase in TRH content and prepro-TRHmessengerRNA (preproTRHmRNA) levels could be demonstrated by RIA and Northern blot analysis, whereas the cellular content of the TRH-like peptide pyroGlu-Glu-Pro-NH2 decreased with time in culture to undetectable levels. The release of TRH could be stimulated by depolarizing concentrations of K+ (55 mM), by the Ca++ ionophore A23187, and by GnRH, but not by CRH or GRF, indicating that TRH is stored in gonadotropes. Moreover, a combined in situ hybridization and immunocytochemical analysis demonstrated colocalization of LH in preproTRHmRNA-positive AP cells. When AP cells were cultured as reaggregates in the same (FCS-containing) medium, only a marginal increase in TRH content and preproTRHmRNA levels was observed. Irrespective of the culture systems and the culture conditions used, TRH gene expression was not observed when FCS was omitted. These results indicate that TRH gene expression more likely reflects derepression, rather than induction, of the TRH gene.

Animals↗

PubMed1997

3,5-diiodo-L-thyronine stimulates type 1 5'deiodinase activity in rat anterior pituitaries in vivo and in reaggregate cultures and GH3 cells in vitro.

Local deiodination of L-thyroxine (T4) to the active thyroid hormone T3 via two 5'deiodinase isoenzymes (5'DI and 5'DII) plays an important role for various T3-dependent functions of the anterior pituitary (AP). Recently, it was reported that 3,5-T2, the 5'deiodination product of T3, acts as a specific agonist in the feedback mechanism on TSH secretion at the pituitary level. We now examined the effects of 3,5-T2 on pituitary 5'deiodinase activities in vivo in male, adult rats and in vitro using rat AP reaggregate cultures and the somatomammotroph cell line GH3. 5'DI activity in the AP was transiently increased after a single injection of 3,5-T2. Serum TSH levels declined, and 24 h after 3,5-T2 application, betaTSH steady-state mRNA levels in the APs were markedly lower. In reaggregate cultures of the AP, 3,5-T2 stimulated 5'DI activity 24 h after application, dose-dependently. Compared with 5'DI activities, those of 5'DII were an order of magnitude lower, in vivo as well as in vitro, and were rapidly and transiently decreased by the higher dose of 3,5-T2. GH3 cells responded to 3,5-T2 and T3 by an 1.7-fold stimulation of 5'DI activity. Stimulation of DNA-binding was demonstrated in electrophoretic mobility shift assays for a specific RXR-containing protein complex with a DR+4 thyroid hormone response element of the human type 1 5'DI promoter using nuclear extracts from GH3 cells treated with 3,5-T2. In summary, 3,5-T2 and T3 exert direct thyromimetic effects on 5'DI activity and TSHbeta expression at the pituitary level. 5'DI is regulated by its substrate(s) and/or products and may serve an important function within the modulation of thyroid hormone-dependent gene expression in the AP.

Analysis of Variance↗

PubMed1997

Regulation of the adenohypophyseal thyrotropin-releasing hormone-degrading ectoenzyme by estradiol.

TRH is inactivated by the TRH-degrading ectoenzyme, a TRH-specific metallopeptidase. At the pituitary level, this enzyme is stringently regulated by thyroid hormones. We describe here gender-related differences and the effect of estradiol (E2) on the expression of this enzyme in the anterior pituitary. Compared with male rats, only about one third of the enzymatic activities and the messenger RNA levels were found in the anterior pituitary of female rats, whereas the TRH receptor transcript levels were found inversely related. When male rats received a single injection of 0.5 microg E2/100 g BW, the enzymatic activity decreased to 65% of control values within 14 h, preceded by a decrease of the transcript levels to 25% of control within 6 h. Basal values were reached again 24-48 h after the injection. E2 had no effect on the expression of the enzyme in the brain. In vivo and with GH3 cells in vitro, E2 effectively counteracted the increase in enzymatic activity induced by T3, whereas neither testosterone nor progesterone, aldosterone, or dexamethasone showed any significant effects. Because the expression of the adenohypophyseal TRH-degrading ectoenzyme is tightly regulated by both T3 and E2 with adequate dynamics, we conclude that this peptidase serves integrative functions for the control of TRH-stimulated hormone secretion.

Aminopeptidases↗

PubMed1997

Significant elevation of tumour-associated isoforms of soluble CD44 in serum of normal individuals caused by cigarette smoking.

While performing a prospective study on sCD44 variant isoforms as tumour markers in certain malignancies, we detected relevant differences in the control group between non-smokers and smokers. For a detailed evaluation of these findings, serum levels of sCD44 variant proteins, including sequences encoded by exon v5 and exon v6, respectively, were adjusted to sex, age and smoking habit. We were able to demonstrate a significant elevation of serum levels of sCD44v5 and sCD44v6 in normal individuals due to cigarette smoking (non-smokers to smokers: sCD44v5: 33 +/- 11 microg/l to 62 +/- 30 microg/l; sCD44v6: 142 +/- 34 microg/l to 232 +/- 86 microg/l). Stepwise multiple linear regression analysis of the concentrations of sCD44v5 and sCD44v6 on the possible influence factors sex, age and smoking habit revealed cigarette smoking as the only factor influencing these isoforms (both p << 0.001). Further investigations have to elucidate a possible clinical importance of these findings in smokers. However, in patients with suspected or proven malignancy the diagnostic specifity of sCD44v5 and sCD44v6 is diminished due to this observation.

Antigens, Neoplasm↗

PubMed1997

Urinary excretion of the TRH-like peptide pyroglutamyl-glutamyl-prolineamide in rats.

TRH-like immunoreactivity (TRH-LI) was estimated in methanolic extracts of rat tissues and blood by RIA using antiserum 4319, which binds most peptides with the structure pGlu-X-ProNH2, or antiserum 8880, which is specific for TRH (pGlu-His-ProNH2). TRH-LI (determined with antiserum 4319) and TRH (determined with antiserum 8880) contents were 8 and 8 ng/g in brain, 216 and 222 ng/g in hypothalamus, 6.5 and 6 ng/g in pancreas, 163 and 116 ng/g in male pituitary, 105 and 77 ng/g in female pituitary, 1 and 0.1 ng/g in salivary gland, 61 and 42 ng/g in thyroid, 12 and 3 ng/g in adrenal, 3 and 0.3 ng/g in prostate, and 11 and 0.8 ng/g in ovary respectively. Blood TRH-LI (antiserum 4319) and TRH (antiserum 8880) levels were 31 and 18 pg/ml in male rats, and 23 and 10 pg/ml in female rats respectively. Unextracted serum obtained from blood kept for at least 1 h at room temperature no longer contained authentic TRH but still contained TRH-LI (males 20.3 +/- 3.1, females 15.9 +/- 3.0 pg/ml; means +/- S.E.M.). Isocratic reverse-phase HPLC showed that TRH-LI in serum is largely pGlu-Glu-ProNH2 (< EEP-NH2), a peptide previously found in prostate and anterior pituitary. In urine, TRH-LI (antiserum 4319) and TRH (antiserum 8880) levels were 3.21 +/- 0.35 and 0.32 +/- 0.04 ng/ml in male rats and 3.75 +/- 0.22 and 0.37 +/- 0.04 ng/ml in female rats respectively (means +/- S.E.M.). Anion-exchange chromatography on QAE-Sephadex showed that urine of normally fed rats contains both basic/neutral TRH-LI (b/n TRH-LI) and acidic TRH-LI (aTRH-LI) in a ratio of approximately 40:60, and further analysis by HPLC indicated that aTRH-LI represents < EEP-NH2. Analysis of food extracts and urine from fasted rats demonstrated that b/n TRH-LI is derived from food particles spilled by the rats during urine collection, while aTRH-LI is endogenously produced. While urinary aTRH-LI levels were higher in female than in male rats (2.99 +/- 0.41 vs 2.04 +/- 0.20 ng/ml), the daily urinary excretion was similar in both sexes (females 15.6 +/- 1.4, males 19.5 +/- 2.0 ng/day). Intravenously injected < EEP-NH2 disappeared from serum with a half-life of approximately 1 h, and was recovered unchanged and quantitatively in urine. In contrast, when < EEP-NH2 was administered with food, only approximately 0.5% was recovered in urine. The urinary clearance rate of serum TRH-LI amounted to 0.52 +/- 0.10 ml/min in males and 0.34 +/- 0.05 ml/min in females. In view of the presence of < EEP-NH2 in the anterior pituitary gland, and the regulation of its content in parallel with gonadotrophins, we examined the possibility that serum < EEP-NH2 is of pituitary origin and correlates with gonadotrophin secretion. However, treatments that alter pituitary < EEP-NH2 content and gonadotrophin release had no effect on serum TRH-LI or urinary aTRH-LI. In conclusion, the TRH-like peptide < EEP-NH2 is present in rat serum and is excreted into the urine. Moreover, < EEP-NH2 in serum and urine is not derived from rat food and is probably not of pituitary origin.

Adrenal Glands↗