Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The manifestations of endocrine derangements in the musculoskeletal system in infancy and childhood are disturbances in growth and maturation and in adulthood are disturbances in maintenance and metabolism. Hypercortisolism during skeletal immaturity suppresses growth. In the adult, hypercortisolism leads to osteoporosis, osteonecrosis, and muscle wasting. Deficiency of growth hormone during skeletal development results in short stature. An excess of growth hormone in a skeletally immature individual results in gigantism, an excess in a skeletally mature individual results in acromegaly. Patients with gigantism have extreme height with normal body proportions. Musculoskeletal manifestations of acromegaly include soft-tissue thickening, vertebral body enlargement, characteristic hand and foot changes, and enthesal bony proliferation. Hyperthyroidism causes catabolism of protein and loss of connective tissue, which manifest as muscle wasting. Deficient levels of thyroid hormone cause defects in growth and development. Severe growth retardation from congenital hypothyroidism is rare because neonatal screening recognizes the disorder and leads to early treatment. The skeletal manifestation of hypergonadism in children is precocious growth and early skeletal maturation. Although the initial precocious growth spurt results in a tall child, early closure of the growth plates results in a short adult. Hypogonadism in the prepubertal child results in delayed adolescence and delayed skeletal maturation. Diabetes mellitus in childhood results in decreased growth, a phenomenon presumed to be secondary to nutritional abnormalities. Generalized osteoporosis and short stature are common. In the adult, generalized osteoporosis may accompany insulin-dependent diabetes mellitus if obesity is absent. Calcification of interdigital arteries of the foot is common in diabetics and uncommon in other conditions. Additional skeletal manifestations relate to complications of diabetes such as peripheral neuropathy and diabetic foot disease.
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PMID:Radiologic manifestations in the musculoskeletal system of miscellaneous endocrine disorders. 198 24

The dwarf mutation in mice interferes with the development of those anterior pituitary cells responsible for production of thyroid stimulating hormone, growth hormone, and prolactin. Myosin isozyme transitions in both cardiac and skeletal muscle were also found to be affected in this mutant. Electrophoresis of native myosins demonstrated that the fetal (V3) to adult (V1) ventricular cardiac isozyme transition was completely blocked in dwarf mice; in contrast, the neonatal to adult fast myosin transition in hind limb skeletal muscle was slowed but not totally inhibited. The persistence of neonatal myosin heavy chain for up to 55-75 d after birth in dwarf mice, as compared with 16 d in normal mice, was directly demonstrated by polypeptide and immunopolypeptide mapping. Morphological examination of 18-36-d-old dwarf skeletal muscles by optical and electron microscopy revealed a relative immaturity, but no signs of gross pathology were evident. Immunocytochemical analysis showed that the abnormal persistence of neonatal myosin occurs in most of the fibers. Multiple injections of thyroxine restored a normal isozyme complement to both cardiac and skeletal muscles within 11-15 d. Therefore, the effects of the dwarf mutation on myosin isozymes can be explained by the lack of thyroid hormone in these animals. Because the synthesis of growth hormone is not stimulated by thyroid hormone in dwarf mice as it would be in normal animals, these results demonstrate that thyroid hormone promotes myosin isozyme transitions independent of growth hormone production.
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PMID:Hereditary pituitary dwarfism in mice affects skeletal and cardiac myosin isozyme transitions differently. 401 84

Studies of the maturation of hypothalamic control of adenohypophyseal hormone secretion are reviewed with particular reference to the somato-tropic axis in the ovine fetus. In the ovine fetus, circulating growth hormone concentrations are 20-fold higher than postnatal concentrations falling in the 72 h prior to delivery. These high fetal growth hormone concentrations are postulated to reflect an immaturity of hypothalamic control mechanisms. Synthetic human growth hormone releasing factor (10 micrograms/kg) markedly stimulates fetal circulating growth hormone release between 77 and 135 days of gestation. The response decreases with advancing maturation. Thus fetal growth hormone release is not under maximal stimulation. Fetal growth hormone, thyrotropin and gonadotropin release is pulsatile in nature and the growth hormone and thyrotropin pulses have exaggerated amplitudes compared to the postnatal pattern. It is suggested that in each case, this enhanced pulsatility is a consequence of immature feedback loops. Stereotaxic lesioning of the fetal median eminence at 110 days of gestation abolishes the pulsatility of fetal growth hormone release. However the basal secretion of growth release remains elevated in some fetuses compared to postnatal growth hormone concentrations. The basis for this high basal rate of secretion is speculative but it is postulated to reflect immaturity of inhibitory control mechanisms, in particular of the negative feedback loop. Neuropharmacological studies of circulating growth hormone release in the perinatal period are reviewed. These demonstrate that the potential for many neurotransmitters to influence fetal circulating growth hormone release has differentiated by midgestation. However antagonist studies have not demonstrated a tonic role for any stimulatory neurotransmitters, only for the inhibitory neurotransmitter, GABA. Growth hormone does not exert a major influence upon fetal growth. Studies of the ontogeny of growth hormone receptors in the ovine liver show that somatotropic receptors are first detected in the newborn lamb suggesting receptor immaturity as the basis for this lack of an effect of growth hormone in utero. The two insulin-like growth factors, IGF-I and IGF-II show different patterns of secretion in the perinatal period. IGF-I levels are low in utero, rise gradually through gestation with a marked postnatal rise perhaps related to the development of hepatic growth hormone receptors. IGF-II levels are high in the fetus and fall over the 3 days prior to delivery but are not affected by fetal decapitation. The role of placental lactogen as a stimulus of fetal IGF-II secretion is suggested.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Functional maturation of the neuroendocrine system in the perinatal period: studies of the somatotropic axis in the ovine fetus. 674 30

The discovery of leptin has generated an extraordinary interest in the field of obesity but also in the understanding of the relationship between metabolic status and the neuroendocrine system. Following the initial demonstration that leptin administration to fasting mice can 'protect' neuroendocrine secretions and prevent the changes that are associated with fasting, the concept has emerged that a normal leptin secretion is a prerequisite for normal neuroendocrine secretions. Several unfavorable metabolic situations are associated with low plasma leptin, increased secretion of hypothalmic neuropeptide Y (NPY), and hypogonadism, and a causal relationship has been evoked. Severe dietary restriction in juvenile female rats is associated with low plasma leptin and sexual immaturity. Cessation of food restriction leads to immediate increase in plasma leptin followed 4 days later by vaginal opening. If food restriction is maintained, central leptin infusion can induce sexual maturation, thus demonstrating that leptin can act as a signal for the onset of puberty. In untreated type-I diabetic rats, hypogonadism is associated with very low plasma leptin and increased hypothalmic NYP synthesis and oestrous cyclicity. Fasting rapidly inhibits growth hormone (GH) secretion in association with low plasma leptin and elevated hypothalmic NPY. Central infusion of leptin to fasting rats was able to completely prevent the collapse of GH secretion and to maintain a normal low NPY synthesis. In summary, normally elevated plasma levels appear to be a prerequisite for normal GH and gonadotropin secretion in the rat. Degradation of metabolic conditions results in a rapid reduction of circulating leptin that could represent the signal for several alterations of neuroendocrine secretions. At the level of the hypothalamus, leptin could act on NPY neurons to transduce part or all of this 'metabolic' message. The possibility that changing plasma levels for leptin also affect peripheral endocrine targets, such as pituitary, ovary, adrenal or pancreas, is likely since these endocrine organs express functional long-term leptin receptors.
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PMID:Metabolic control of sexual function and growth: role of neuropeptide Y and leptin. 972 77

Changes of growth hormone receptivity in the ovary during the reproductive cycle were studied in rainbow trout (Oncorhynchus mykiss). A method for characterizing growth hormone receptors in crude ovary homogenate was required for this. Binding of radiolabelled recombinant rainbow trout growth hormone (125I-labelled rtGH) to crude ovary preparation was dependent on ovarian tissue concentration. The sites were specific to growth hormone, with no affinity for prolactins and gonadotrophins. Similar high affinities for 125I-labelled rtGH were obtained with crude ovary (4.2 x 10(9) +/- 0.3 mol l-1) and crude liver preparations (4.9 x 10(9) +/- 0.1 mol l-1) at all stages of ovogenesis, and with ovarian membrane preparations (8.2 x 10(9) mol l-1) tested at the beginning of vitellogenesis. Ovarian growth hormone receptor concentration was highest during the early phases of follicular development (endogenous vitellogenesis: 315-310 fmol g-1 ovary) and decreased regularly during oocyte and follicular growth (exogenous vitellogenesis) to reach a minimal value at oocyte maturation (42 fmol g-1 ovary). In postovulated fish, binding was at a similar level (297 fmol g-1 ovary) to that found in endogenous vitellogenesis. Conversely, the absolute binding capacity of the whole ovary was low from immaturity to early exogenous vitellogenesis (0.1-0.6 pmol per pair of gonads), increased slowly during vitellogenesis and more markedly during rapid oocyte growth and at the time of final maturation (10.8 pmol per pair of gonads). In postovulated fish, the absolute binding capacity decreased partially (4.4 pmol per pair of gonads). Mean hepatic growth hormone receptor concentration did not vary with the reproductive stage for most of the cycle (3.0-4.5 pmol g-1 liver) except in endogenous vitellogenesis where significantly higher concentrations were observed (6.7 pmol g-1 liver). Individual ovarian growth hormone receptor concentrations were correlated with hepatic growth hormone receptor concentrations, indicating that they are regulated in a similar way. We conclude that growth hormone receptors are present in the ovary during the entire ovarian cycle in rainbow trout, probably mainly in somatic cells as indicated by the same concentration of binding sites in immature and in postovulated fish. Growth hormone is potentially important during oocyte recruitment in vitellogenesis and initiation of growth and during final follicular maturation.
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PMID:Growth hormone receptors in ovary and liver during gametogenesis in female rainbow trout (Oncorhynchus mykiss). 1043 33

Although extensive data are available on the impact of nutrient and protein administration on growth, plasma amino acids, and nitrogen balance in the newborn and growing infants, relatively few studies have carefully examined the dynamic aspects of protein metabolism in vivo and particularly in the micropremie or ELBW infant. These studies show that the very preterm infants, either because of immaturity or because of the intercurrent illness, have high rates of protein turnover and protein breakdown. This high rate of proteolysis is not as responsive to nutrient administration. Intervention strategies aimed at promoting nitrogen accretion, such as insulin, human growth hormone, or glutamine, have not thus far resulted in enhanced protein accretion and growth. This may be, in part, due to limitations in delivery of adequate calorie and nitrogen.
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PMID:Protein metabolism in the extremely low-birth weight infant. 1069 May 63

It is proposed an animal model consisting of young male, L-tryptophan-deprived, namely 5-HT-free rats since their ontogenesis. This was obtained by feeding their mothers with a L-tryptophan-free (tf) diet since the day 1 of pregnancy. They were studied and compared with control rats of the same ages fed with a complete diet. Already at birth tf-litters were significantly underdeveloped as compared to the control newborn rats. Postnatal growth was in the tf-rats so poor that it worsened into a stricking dwarfism characterized by physical immaturity, muscular hypotrophy with alterations of motor activity and impairment of the hypothalamo-pituitary-axis. A radioimmunological study of growth hormone (GH) showed in tf-rats dramatic low plasma levels of the hormone, thus confirming the existence of serotonergic hypothalamo-pituitary pathways for GH in normal animals. By histological and ultrastructural examinations, hypotrophy and degenerative alterations of the muscle fibers could be observed. The possible causes for this finding are extensively considered and discussed.
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PMID:Effects of a tryptophan deficient diet on the morphology of skeletal muscle fibers of the rat. Preliminary observations at neuroendocrinological and submicroscopical levels. 1132 86

Proliferating cells in the male rat anterior pituitary at 1, 3, 5, and 8 weeks of age were labeled with bromodeoxyuridine (BrdU) and studied by light and electron microscopic immunocytochemistry using anti-BrdU. They decreased in number from 402+/-31/mm(2) at 1 week to 50+/-1.5/mm(2) at 8 weeks, while their cell area increased by about twofold during this period. They had a slightly higher nucleus/whole cell (N/C) ratio than non-proliferating cells. According to their ultrastructure we classified them into granular and agranular cells. The percentage of granular cells ranged from 73% to 82% of all the proliferating cells during the period studied. They had many granules of various sizes and shapes, and some contained growth hormone and prolactin. Agranular cells, constituting 18-27% of proliferating cells, were small and had a high N/C ratio, indicating their immaturity. Moreover, they showed several features of folliculo-stellate (FS) cells: they showed no secretory granules in the cytoplasm, extended thin cytoplasmic processes, and sometimes they constructed a follicle among them. These results suggest: (1) the majority of proliferating cells were mature cells producing anterior pituitary hormone(s) and (2) most of the agranular proliferating cells maybe FS cells. The possibility of the latter is discussed.
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PMID:Proliferating cells in the rat anterior pituitary during the postnatal period: immunoelectron microscopic observations using monoclonal anti-bromodeoxyuridine antibody. 1294 35

Sprague-Dawley rats that had been subjected 2 months previously to partial resection (10 per cent) of the small intestine and an equal number of control rats were injected with tritiated thymidine and sacrificed at intervals during the subsequent 16 hours. Segments of duodenum, jejunum and ileum were prestained by the Feulgen technique and radioautographed. The proportion of crypt cells bearing labeled nuclei, the percentage of labeled crypt cells in mitosis and the appearance of labeled crypt cells on the villi were determined. Comparison of control and resected rats showed that (a) the proportion of intestinal crypt cells incorporating thymidine was considerably greater and uniformly high throughout the shortened intestine, (b) the life cycle of crypt cells was slightly reduced, and was uniform throughout the shortened intestine, and (c) the time during which cells were retained in crypts was markedly reduced. On the basis of persistent, generalized increase in the production of crypt cells, and on prior evidence that the epithelial cells of shortened intestine continue to have a brief life span and evidence of metabolic immaturity, the existence of a humoral factor, tentatively called "intestinal epithelial growth hormone," is postulated.
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PMID:POPULATION DYNAMICS OF INTESTINAL EPITHELIA IN THE RAT TWO MONTHS AFTER PARTIAL RESECTION OF THE ILEUM. 1408 56

Morbidity and mortality of preterm neonatal calves are higher than of calves born at normal term, possibly and in part due to immaturity of physiological functions. Physiological parameters were therefore studied during the first week of life in seven preterm calves, born on day 277 of gestation after dams were injected prostaglandin F2alpha and flumethason. Calves were fed colostrum of the first milking for the first 3 days and from day 4 to day 7 the same colostrum diluted with milk replacer. Body weight increased during the first week of life by 2.2 kg. Heart rate and respiratory rate were always relatively high, whereas values of rectal temperature, blood gases, haematological, metabolic and endocrine traits were in the range and behaved similarly as is the experience in full-term neonatal calves. Major exceptions were glucose and insulin, the concentrations of which barely rose postprandially, and growth hormone, the responses of which to growth hormone releasing factor analogue 1-29 were extremely variable and in part very small. In conclusion, calves born 2 week before normal term that survived the first week of life, although physiologically immature, were well able to handle ingested nutrients and to control their metabolism.
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PMID:Physiological traits in preterm calves during their first week of life. 1537 20


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