Immunoreactive thyrotrophin-releasing hormone like material (IR-TRH LM) in human cord blood: high circulating serum levels but possible non-identity with hypothalamic TRH

1983 ◽  
Vol 104 (3) ◽  
pp. 319-326 ◽  
Author(s):  
J. M. Kaufman ◽  
A. Elewaut ◽  
A. Vermeulen
Keyword(s):  
Pregnant Women ◽  
Equilibrium Dialysis ◽  
Serum Samples ◽  
Human Cord Blood ◽  
In Vitro Degradation ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Cord Serum ◽  
Control Serum

Abstract. Levels of immunoreactive thyrotrophin-releasing hormone like material (IR-TRH LM) were measured in paired maternal and umbilical cord serum samples (n = 45) and in serum of non-pregnant women (n = 63), using a sensitive and specific radioimmunoassay. In all pairs IR-TRH LM in venous cord serum (mean 91.3 pg/ml, range 20–270) was markedly elevated as compared to maternal serum (mean 13.5 pg/ml, range 0–37, P < 0.001, the maternal levels being similar to those in non-pregnant women (mean 12.0 pg/ml, range 0–39, P > 0.1). In 23 cases IR-TRH LM was also measured in arterial cord serum: arterial and venous cord levels were highly significantly correlated (r = 0.904) with higher arterial levels in 22 out of 23 cases (mean 117.8 pg/ml, range 32–280 and 90.6 pg/ml, range 20–270, P < 0.001), suggesting that cord IR-TRH LM is not of placental origin. There was no correlation between individual levels of IR-TRH LM and either TSH, T4, T3 or FT4 levels in either maternal or cord serum. Agar gel electrophoresis and equilibrium dialysis of adult and cord serum pre-incubated with [125I]TRH or [3H]TRH revealed no protein binding. Cord IR-TRH LM was immunologically, as well as in paper electrophoresis and in gelfiltration, indistinguishable from synthetic and hypothalamic TRH. In vitro degradation of synthetic TRH was much slower in cord serum as compared to maternal and control serum (P < 0.001). In vitro degradation of cord IRTRH LM could not be demonstrated, neither by cord serum itself nor by adult serum, this in contrast to hypothalamus extracted TRH which was readily degraded by adult serum. Neither the presence of an inhibiting substance, nor methodological factors seem to account for the apparently different behaviour of cord IR-TRH. It is suggested that circulating IR-TRH could be closely related, but still different from tissue extracted and synthetic TRH.

AGE-RELATED CHANGES IN THE DEGRADATION OF THYROTROPHIN RELEASING HORMONE BY HUMAN AND RAT SERUM

1980 ◽  
Vol 86 (3) ◽  
pp. 397-402 ◽  
Author(s):  
NICKI WHITE ◽  
E. C. GRIFFITHS ◽  
S. L. JEFFCOATE ◽  
R. D. G. MILNER ◽  
M. A. PREECE
Keyword(s):  
Physiological Role ◽  
Serum Samples ◽  
Rat Serum ◽  
Thyrotrophin Releasing Hormone ◽  
Male And Female ◽  
Releasing Hormone ◽  
Clear Cut ◽  
Age Related ◽  
Age Related Changes

Changes in the rate of in-vitro degradation of thyrotrophin releasing hormone (TRH) in serum as related to age have been investigated in the rat and man. In rats, no inactivation was found up to the age of 15 days but thereafter an age-related increase in inactivation was detected with approximately 75% inactivation in 60 min at 40 days and reaching a maximum of 88–93% inactivation in adult male and female animals. The human serum samples studied (both male and female) showed a similar but less clear-cut pattern of inactivation of TRH compared with that found in the rat. A physiological role for these age-related changes in the degradation of TRH remains to be established but it has been concluded that the changes observed in both rat and man may be associated with growth and development, possibly by facilitating feedback control of thyrotrophin secretion through the degradation of TRH.

EFFECT OF THYROID STATUS ON THE THYROTROPHIN-RELEASING HORMONE-DEGRADING ACTIVITY OF RAT SERUM

1976 ◽  
Vol 71 (1) ◽  
pp. 13-19 ◽  
Author(s):  
N. WHITE ◽  
S. L. JEFFCOATE ◽  
E. C. GRIFFITHS ◽  
K. C. HOOPER
Keyword(s):  
Thyroid Hormone ◽  
Human Serum ◽  
Thyroid Function ◽  
Thyroid Status ◽  
Rat Serum ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Tsh Levels

SUMMARY The TRH-degrading activity of rat serum in vitro is five times more potent than that of human serum. In rats, it is significantly reduced in hypothyroidism (thiouracil-induced) and significantly increased in hyperthyroidism (T3 or T4-induced). This suggests a possible role in the regulation of adenohypophysial-thyroid function which is probably, in turn, dependent on thyroid hormone, rather than TSH, levels.

Stimulatory effect of thyrotrophin-releasing hormone (TRH) on the release of luteinizing hormone (LH) from rat anterior pituitary cells in vitro

1983 ◽  
Vol 61 (2) ◽  
pp. 186-189 ◽  
Author(s):  
Noboru Fujihara ◽  
Masataka Shiino
Keyword(s):  
Luteinizing Hormone ◽  
Anterior Pituitary ◽  
Pituitary Cells ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Anterior Pituitary Cells ◽  
Lh Release ◽  
Lh Rh

The effect of thyrotrophin-releasing hormone (TRH, 10−7 M) on luteinizing hormone (LH) release from rat anterior pituitary cells was examined using organ and primary cell culture. The addition of TRH to the culture medium resulted in a slightly enhanced release of LH from the cultured pituitary tissues. However, the amount of LH release stimulated by TRH was not greater than that produced by luteinizing hormone – releasing hormone (LH–RH, 10−7 M). Actinomycin D (2 × 10−5 M) and cycloheximide (10−4 M) had an inhibitory effect on the action of TRH on LH release. The inability of TRH to elicit gonadotrophin release from the anterior pituitary glands in vivo may partly be due to physiological inhibition of its action by other hypothalamic factor(s).

scholarly journals Genetic evidence for fetal origin of transcobalamin II in human cord blood

Blood ◽  
1983 ◽  
Vol 62 (1) ◽  
pp. 234-237 ◽  
Author(s):  
HJ Porck ◽  
M Frater-Schroder ◽  
RR Frants ◽  
L Kierat ◽  
AW Eriksson
Keyword(s):  
Cord Blood ◽  
Polyacrylamide Gel Electrophoresis ◽  
Maternal Serum ◽  
Control Group ◽  
Transplacental Passage ◽  
Healthy Male ◽  
Serum Samples ◽  
Human Cord Blood ◽  
Cord Serum ◽  
Transcobalamin Ii

Abstract Phenotypes of transcobalamin II (TC2) were determined in 95 maternal- cord serum pairs in order to identify the origin of TC2 in human cord blood. Unsaturated (apo) TC2 in serum was labeled with radioactive (57Co) cobalamin (CbI) and separated into isoproteins by polyacrylamide gel electrophoresis and autoradiography. Discordancy between the maternal and the cord serum type was observed in 45% of the pairs. The results demonstrated that, at the end of pregnancy, the fetus is capable of TC2 synthesis and that there is no detectable transplacental passage of maternal apo-TC2. Presence of maternal saturated (holo) TC2 in cord serum could be excluded in 9 informative discordant pairs by exchanging endogenously bound CbI with 57Co-CbI. Our finding that TC2 in human cord serum is of fetal rather than maternal origin suggests an essential role for fetal TC2 in CbI utilization and appears to contradict the hypothesis that transplacental passage of maternal TC2 may explain the normal fetal development in cases of congenital TC2 deficiency. The total immunoreactive TC2 content in 23 maternal serum samples collected at the end of pregnancy (812 +/- 175 pM CbI equivalent) was significantly higher than in the corresponding cord sera (605 +/- 148 pM; p less than 0.001) and did not significantly differ from the value in a control group of healthy male and female adults (841 +/- 192 pM). At the end of pregnancy, the apo-TC2 content in 12 maternal serum samples (760 +/- 347 pM) was significantly higher than in the corresponding cord sera (501 +/- 254 pM; p less than 0.05) and did not significantly differ from the value in the control group (747 +/- 137 pM).

Effects of synthetic mammalian thyrotrophin releasing hormone, somatostatin and dopamine on the secretion of prolactin and growth hormone from amphibian and reptilian pituitary glands incubated in vitro

1984 ◽  
Vol 102 (2) ◽  
pp. 175-180 ◽  
Author(s):  
T. R. Hall ◽  
A. Chadwick
Keyword(s):  
Rana Catesbeiana ◽  
Apparent Effect ◽  
Lower Vertebrate ◽  
Thyrotrophin Releasing Hormone ◽  
Factors Affecting ◽  
Releasing Hormone ◽  
Hypothalamic Extract ◽  
Pituitary Glands ◽  
Regulation Of Secretion

ABSTRACT Pituitary glands of grassfrog (Rana pipiens), bullfrog (Rana catesbeiana), clawed toad (Xenopus laevis) and two species of terrapin (Chrysemys picta and Pseudemys scripta) were incubated in medium containing hypothalamic extract (HE), thyrotrophin releasing hormone (TRH), somatostatin, dopamine, or combinations of these treatments. Prolactin and GH concentrations in the medium were determined by densitometry after polyacrylamide-gel electrophoretic separation. Hypothalamic extract stimulated secretion of both hormones in all species tested. Thyrotrophin releasing hormone stimulated secretion of prolactin and GH, showing a biphasic pattern of response. Dopamine had little effect alone, but inhibited HE-and TRH-stimulated release of prolactin, but not GH, in both amphibia and reptiles. Somatostatin by itself had no apparent effect on release of hormones, but it inhibited HE- and TRH-stimulated release of GH from both amphibian and reptilian pituitary glands. These results indicate that factors affecting mammals and birds also interact in the regulation of secretion of prolactin and GH in lower vertebrate species. J. Endocr. (1984) 102, 175–180

THE INFLUENCE OF OESTROGEN ADMINISTRATION IN VIVO ON IN VITRO PROLACTIN RELEASE

1979 ◽  
Vol 92 (3) ◽  
pp. 437-447 ◽  
Author(s):  
Sandford Jaques ◽  
Richard R. Gala
Keyword(s):  
Time Of Day ◽  
Ovariectomized Rat ◽  
Prolactin Release ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Stable Pool ◽  
Releasable Pool ◽  
Storage Pools

ABSTRACT The influence of oestrogen administered to the ovariectomized rat on the interaction between dopamine (DA) and thyrotrophin releasing hormone (TRH) on the release of radioimmunoassayable (RIA) and [3H] leucine incorporated into prolactin ([3H]PRL) was examined in vitro. Dopamine had a more marked suppressing effect on newly synthetized PRL (80 %), as determined [3H]PRL, than on total PRL (50 %), as determined by RIA-PRL. The administration of 5 μg of oestradiolbenzoate (OeB) for 7 days resulted in blocking the suppressing effect of DA when RIA-PRL was measured but not when [3H]PRL was measured. The administration of 5 μg of OeB enabled TRH to partially override the suppressing effect of DA and the degree of response was more marked when RIA-PRL was measured than when [3H]PRL was measured. The administration of 50 μg of OeB for 3 days enabled TRH to override the DA blockade of prolactin release to levels comparable to that of the control when RIA-PRL was measured but had little to no effect on [3H]PRL. The results are discussed in relation to the two storage pools of PRL in the pituitary and the data suggest that DA acts predominantly to suppress the newly synthetized, rapidly releasable pool. Oestrogen acts to block DA action on the older more stable PRL pool. The ability of TRH to override the DA blockade of PRL release depends upon the presence of oestrogen; here TRH acts predominantly on the older more stable pool of PRL. Oestrogen's action on disrupting the DA suppression of PRL release appears to be related to the time of day the hormone is administered subsequent to when the pituitary is exposed to DA in vitro.

Rapid assay for in vitro degradation of luteinizing hormone releasing hormone

1982 ◽  
Vol 127 (2) ◽  
pp. 418-425 ◽  
Author(s):  
H. Berger ◽  
H. Schäfer ◽  
E. Klauschenz ◽  
E. Albrecht ◽  
B. Mehlis
Keyword(s):  
Luteinizing Hormone ◽  
In Vitro Degradation ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Rapid Assay
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