Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Any biological function is at least bimolecular and its evolution therefore is at least dual, with variations in two lines of molecules. The hormone specificity results from a particular fit between the three-dimensional structure of the agent and that of the receptor but, because receptors are not known at the structural level, a discussion on the evolution of the polypeptide hormones is mainly limited to the possible progressive changes of the latter. As for other proteins (enzymes, oxygen carriers etc.) two degrees of complexity can be distinguished according to whether the hormone comprises one or several polypeptide chains. Protein assembly can bring new biological properties, each subunit playing a particular role. In this case, the 'internal' evolution (chain-chain interactions) overlaps the 'external' evolution (hormone-receptor contacts). The 'monomeric' hormones present the following problems: evolution of the prohormone and of the converting enzyme (for insulin), duplication and differentiation of two lines of hormones either by amino acid substitutions (neurohypophysial hormones and neurophysins) or by substitutions and size modifications (corticotropin and lipotropin), duplication and fusion leading to internal homology in the single polypeptide chain (somatotropin, prolactin, placental lactogen). The 'dimeric' hormones lead to several problems: successive duplications giving different subunits, selective associations between subunits, unequal rates of evolution of the subunits, the function of each subunit (lutropin, follitropin, thyrotropin, choriogonadotropin). An attempt is made to integrate the evolution of polypeptide hormones in the frame of the evolution of proteins.
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PMID:Molecular evolution of the polypeptide hormones. 78 77

Human placental villus tissue contains opioid receptors and peptides. Kappa opioid receptors (the only type present in this tissue) were purified with retention of their binding properties. The purified kappa receptor is a glycoprotein with an apparent molecular weight of 63,000. Two opioid receptor mediated functions were identified in trophoblast tissue, namely regulation of acetylcholine and hormonal (human chorionic gonadotrophin and human placental lactogen) release. Placental content of kappa receptors increases with gestational age. Term placental content of kappa receptors correlates with route of delivery (higher in those abdominally obtained). Opioid use and/or abuse during pregnancy affects placental receptor content at delivery, as well as its mediated functions. Opioid peptides identified in placental extracts were beta-endorphin, methionine enkephalin, leucine enkephalin and dynorphins 1-8 and 1-13. Dynorphin 1-8 seem to be the predominant opioid peptide present in placental villus tissue.
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PMID:Properties and functions of human placental opioid system. 130 34

The role of a high CRH level in normal pregnancy remains unknown. Therefore we evaluated the concentrations of CRH and the related hormones in patients with pregnancy-induced hypertension. Fourteen women with pregnancy-induced hypertension, aged 20-39, at 30-39 gestational week, were investigated. The control group consisted of 20 healthy pregnant women matched according to gestational age. Plasma CRH beta-endorphin-like immunoreactivity, cortisol, and human placental lactogen were measured by radioimmunoassay, ACTH by an immunoradiometric method. It was found that in hypertensive patients the mean CRH concentration was significantly higher (4257 +/- 840 (SEM) ng/l) than that in healthy pregnant women (1083 +/- 227 ng/l, p less than 0.001). The concentration of ACTH, however, was only slightly higher 65.0 +/- 6.0 vs 50.7 +/- 2.5 ng/l p less than 0.025, whereas the differences in beta-endorphin, cortisol and human placental lactogen were not significant. In both groups there was no correlation between the CRH level and those of the related hormones. In healthy pregnant women the CRH level closely correlated with gestational age (r = 0.76, p less than 0.001), whereas in patients with hypertension no such correlation was present (r = 0.29). We assume that the marked enhancement of plasma CRH in pregnancy-induced hypertension is probably caused by its decreased breakdown in ischemic placental tissue, but its increased synthesis in the placenta and its indirect counterregulatory hypotensive role must also be considered.
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PMID:Enhancement of plasma corticotropin-releasing hormone in pregnancy-induced hypertension. 214 45

This article reviews the current state of our knowledge about the hormonal basis of maternal behavior in the rat. Considered are the ovarian hormones estrogen and progesterone, the pituitary hormones beta-endorphin and prolactin, and the hormone oxytocin, secreted by several hypothalamic nuclei and associated brain regions. The hormones of pregnancy, estrogen and progesterone, prime the female to respond to a terminal rise in estrogen that stimulates a high level of maternal responsiveness even before parturition begins. Studies on the role of prolactin, using hypophysectomy, prolactin release blockers and anterior pituitary and prolactin replacement, indicate that prolactin is required for the ovarian hormones to be effective in stimulating maternal behavior. During the latter half of pregnancy, placental lactogen may displace prolactin in this role. Although prolactin serves as a chronic stimulus for maternal behavior, it also may act over a short period. Oxytocin stimulates maternal behavior in a specific strain of rat, but not in other strains, and only when administered introcerebroventricularly (ICV) in estrogen-primed females. The decline in the high brain levels of beta-endorphin around parturition has been proposed as a requirement for the onset of maternal behavior; morphine blocks the onset of maternal behavior and disrupts ongoing maternal behavior and maternal aggression in lactating females. However, blocking beta-endorphin action at parturition interferes with pup cleaning and eating of the placenta as well.
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PMID:Hormonal basis during pregnancy for the onset of maternal behavior in the rat. 296 17

In oat cell (small cell) carcinoma and, to some extent, in other histological types of lung cancer, improved forms of treatment have resulted in prolongation of survival and even cure. Progress is hampered by the lack of reliable biochemical markers such as those which have completely changed the management and outlook in testicular and gestational carcinoma. Carcinoembryonic antigen (CEA) has been of some value. Raised circulating levels of calcitonin and of adrenocorticotropic hormone (ACTH) are found in many patients with lung cancer but have not proved as useful for monitoring disease progression. It is probable that since lung tumors form a heterogeneous population, production of markers varies with histological type. Our approach has been to affinity purify those polyclonal antisera to potential lung tumor markers which are not yet available as monoclonal hybridoma antibodies and to examine 10 representative resection specimens of each of the four common carcinoma types--squamous, adeno-, large cell, and small cell using an indirect immunoperoxidase localization technique on formalin-fixed paraffin-embedded sections. Substances localized included CEA, epithelial membrane antigen, calcitonin, alpha and beta subunits of human chorionic gonadotropin, and human placental lactogen.
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PMID:Biological markers in lung cancer: an immunocytochemical approach. 618 9

In roughly 10 patients with lung cancer of various histologic types, the levels of hormones adrenocorticotropin (ACTH), calcitonin, parathormone, beta-choriogonadotropin (HCG), human placental lactogen (HPL), growth hormone (HGH), and prolactin were determined by radioimmunoassay. The ACTH level was elevated in 30% of patients with oat cell carcinoma and in 26% of patients with large cell carcinoma. Calcitonin levels were increased in 48% of patients with oat cell carcinoma. Elevated levels of HCG were found in 33% of patients with oat cell carcinoma, in 26% of patients with large cell carcinoma, and in 19% of patients with squamous cell carcinoma. Parathormone was increased in 32% of patients with squamous cell carcinoma in 27% of patients with oat cell carcinoma, and in a few patients with large cell carcinoma. Prolactin, HCG and HPL were present only in single cases. Elevated levels of at least one hormone were found in 65.2% of all patients, and in 78% of the patients with oat cell carcinoma. Serial determinations of ACTH and calcitonin showed that these hormones are useful for monitoring therapy in lung patients. There was no relation between hormone levels and the clinical stage of disease.
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PMID:Ectopic hormones in lung cancer patients at diagnosis and during therapy. 624 92

Placental peptides, such as human chorionic gonadotropin (hCG) and human placental lactogen (hPL), which have marked homologies to pituitary peptides, were described in the early part of this century. Recently, the presence in placenta of additional peptides previously demonstrated as occurring in other tissues, such as brain and pituitary, has been reported. Their presence in placenta has been attributed to similar embryological origin of the tissues which share these peptides, although this has by no means been proven. Placental concentrations of these recently described peptides are several orders of magnitude lower than described for their original sites of production. In many instances, definitive characterization of structural identity with their extraplacental counterparts has not been performed, but has been based on indirect evidence obtained by immunoassay or immunocytochemistry. Evidence of placental synthesis has been obtained for hCG, hPL, and pro-opiomelanocortin (the precursor molecule for adrenocorticotropic hormone (ACTH), B-lipotropin (B-LPH), alpha-melanocyte-stimulating hormone (alpha-MSH), beta-endorphin, and other thus far uncharacterized peptides). Possible functions for the recently described peptides might include actions on the maternal or fetal systems or local (paracrine) actins affecting other placental constituents, although to date no definitive physiological roles have been demonstrated.
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PMID:Placenta as a source of 'brain' and 'pituitary' hormones. 627 87

Detailed endocrinological studies were performed during and after the eighth pregnancy of a 38-year-old woman who had eight spontaneous pregnancies after the onset of hypopituitarism secondary to massive postpartum hemorrhage. Hormonal replacement therapy was not provided during seven pregnancies and all terminated in spontaneous abortions. Studies of pituitary function during and after the eighth pregnancy demonstrated that the patient had measurable amounts of growth hormone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), thyrotropin (TSH), adrenocorticotropin (ACTH), and prolactin in her plasma under basal conditions but that these hormones did not increase approximately in response to pregnancy, stress, and specific stimuli. Evaluation of placental function at 26 weeks gestation by measurement of estradiol, progesterone, human placental lactogen, and chorionic gonadotropin revealed no abnormality. Hormone replacement therapy during the eighth pregnancy was associated with the delivery of normal premature infant at 32 weeks gestation. In addition to these studies, a critical review of the literature was undertaken to more clearly define the clinical and laboratory features of pregnancy in Sheehan's syndrome.
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PMID:Pregnancy in Sheehan's syndrome. Report of a case and review. 699 98

Prolactin plays major roles in maintaining the corpora lutea of pregnancy and in the synthesis of milk during lactation. The hypothalamic mechanisms involved in these functions have been investigated. Mating leads to a surge of prolactin and programs daily surges during early pregnancy. The expression of Fos-immunoreactivity shows that mating activates several hypothalamic nuclei, particularly the arcuate nucleus and medial preoptic area. In the arcuate nucleus, mating is associated with Fos expression in beta-endorphin neurons, and infusion of naloxone blocks both mating-induced and diurnal prolactin surges. Tyrosine hydroxylase-immunoreactive dopamine neurons appear not to participate in surge generation. However, after day 10 of gestation the secretion of placental lactogens suppresses prolactin secretion via activation of dopamine neurons without involvement of beta-endorphin neurons. Intracerebroventricular implantation of placental lactogen-secreting cells will block pregnancy prolactin surges, increase Fos expression in dopamine neurons, and increase tyrosine hydroxylase activity. During lactation the mechanisms regulating dopamine and beta-endorphin neurons are further modified. In early lactation a prolactin-induced increase in tyrosine hydroxylase activity leads to negative feedback, but this effect is lost by mid-lactation. Overriding this negative feedback is the inhibitory effect that suckling has on dopaminergic activity. This may involve beta-endorphin-mediated inhibition of dopamine neurons, as naloxone causes a marked increase in tyrosine hydroxylase activity and suppression of circulating prolactin. However, removal of tonic dopamine inhibition is not sufficient to account for the high levels of prolactin attained during lactation, and additional releasing factors are probably involved. In situ hybrization histochemistry for the most recent candidate, prolactin-releasing peptide, suggests that this may involve brain stem neurons that co-localize noradrenaline. Thus, prolactin secretion during pregnancy and lactation involve complex interactions of regulatory factors and plasticity of neuronal responsiveness.
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PMID:Regulation of prolactin secretion during pregnancy and lactation. 1158 29

The human placenta performs various, important functions essential for the maintenance of pregnancy and development of the fetus. Its secretory diversity surpasses any of the other endocrine organs. The placenta is provided with precursors of hormones by the mother as well as by the fetus. It synthesizes and secretes steroid and protein hormones, growth factors, cytokines. The paper is the review of the present knowledge of steroid hormones (progesterone, estrogens), in particular their synthesis and functions in fetoplacental unit. The protein hormones (chorionic gonadotropin, placental lactogen) are also discussed. The last findings concerning placental gonadotropin-releasing hormone, corticotropin-releasing hormone, leptin, activin, inhibin, follistatin and urocortin are presented. The endocrinology of the placenta is considered to be a progressive field of science. The performed studies elucidate the role of the newly identified hormones in the placenta. It is believed, that research on endocrinology of the placenta contributes to the development of perinatology and, moreover, they improve the prenatal care.
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PMID:[The endocrinology of the human placenta]. 1504 14


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