Puromycin analogs: action of adrenocorticotropic hormone and the role of glycogen

The effect of the injection into rats of analogs of puromycin, 6-dimethylaminopurine, and the aminonucleoside of puromycin on the stimullation of steroidogenesis by adrenocorticotropic hormone was coin pared with that of puromycin and cycloheximide. This stimulation was blocked only by the antibiotics, which also inhibited adrenal protein synthesis. Glycogenolysis is not associated with the primary mechanism of the adrenocorticotropic hormone stimnulation of steroid hormone biosynthesis in rats.     

Pituitary gastrins occur in corticotrophs and melanotrophs

The gut hormone gastrin was identified in pituitary cells containing adrenocorticotropic hormone and alpha-melanocyte--stimulating hormone by region-specific immunocytochemistry and radioimmunoassay. Smaller amounts of gastrin were found in nerve fibers of the neural lobe and pituitary stalk. Since adrenocorticotropic hormone--like peptides occur in antropyloric gastrin cells, these data indicate a considerable similarity in peptide composition of pituitary and gastrointestinal endocrine cells and reinforces questions of multiple hormone production.     

Isolated adrenal cortex cells: hypersensitivity to adrenocorticotropic hormone after hypophysectomy

Cells from the adrenals of hypophysectomized rats (up to 28 days after operation) require less adrenocorticotropic hormone to induce one-half maximal rate of production of 3',5'-adenosine monophosphate than do cells from the adrenals of intact rats. A corresponding increase in sensitivity is reflected in the steroidogenic response to adrenocorticotropic hormone up to 2 days after hypophysectomy.     

Evidence for homologous actions of pro-opiocortin products

alpha-Melanocyte-stimulating hormone (alpha-MSH), a modified fragment of adrenocorticotropic hormone, derives from the same biosynthetic route as beta-endorphin and is stored by the same arcuate neurons. Microinjection of alpha-melanocyte-stimulating hormone and several related peptides into the periaqueductal gray matter significantly reduced responsiveness to pain and had a behavioral profile similar to that produced by beta-endorphin.     

Dexamethasone fails to suppress beta-endorphin plasma concentrations in humans and rhesus monkeys

In humans and rhesus monkeys, dexamethasone decreased concentrations of plasma cortisol but did not alter circulating beta-endorphin immunoreactivity. Contrary to current theory suggesting that pituitary beta-endorphin and adrenocorticotropic hormone are controlled by identical regulatory mechanisms for synthesis and release, our evidence suggests that in higher primates the established glucocorticoid feedback mechanism for the adrenocorticotropic hormone-cortisol system does not regulate beta-endorphin secretion in the same way.     

Identification of pro-opiomelanocortin-derived peptides in the human adrenal medulla

Extracts from adult human adrenals contained high concentrations of immunoreactive beta-endorphin and alpha-melanotropin. Lower quantities of immunoreactive adrenocorticotropic hormone could also be detected. Distribution studies showed the presence of pro-opiomelanocortin fragments in the adrenal medulla. No alpha-melanotropin, beta-endorphin, or adrenocorticotropic hormone could be found in adrenal extracts from several other mammalian species. Analysis of the beta-endorphin-like immunoreactivity using region specific radioimmunoassays interfacing with gel filtration and reverse-phase high-performance liquid chromatography showed the majority of the beta-endorphin-like material to exist as nonacetylated beta-endorphin-(1-31) with a small percentage of lipotropin-sized molecules. The alpha-melanotropin-like immunoreactivity cochromatographed on gel filtration and reverse-phase high-performance liquid chromatography with desacetyl alpha-melanotropin. The data suggest that pro-opiomelanocortin is expressed in the adrenal medulla of humans but is not detectable in the adrenal glands of many other mammalian species.     

Isolated adrenal cells: adrenocorticotropic hormone, calcium, steroidogenesis, and cyclic adenosine monophosphate

Corticosterone production by isolated adrenal cells in response to adrenocorticotropic hormone is reduced when the cells are incubated in a medium that contains no calcium. This reduction is associated with an equal reduction of accumulation of cyclic adenosine monophosphate. Production of corticosterone and accumulation of cyclic adenosine monophosphate are increased when the calcium concentration in the medium is increased (from zero to 7.65 millimolar). This is in contrast to the situation in "subcellular membrane fragments" of adrenal tissue where high calcium in the medium (> 1.0 millimolar) inhibits cyclic adenosine monophosphate accumulation. We propose that adenyl cyclase in the intact plasma membrane is located in a compartment wherein calcium concentration is low and remains unaffected by the concentration of calcium in the extracellular space. It is proposed that, as the concentration of calcium in the incubation medium is increased from zero to 7.65 millimolar, the strength of the signal generated by the interaction of adrenocorticotropic hormone with its receptor and transmitted to the adenyl cyclase compartment is proportionately increased.     

Establishment of four functional, clonal strains of animal cells in culture

The single-cell plating technique was used to develop four clonal cell lines that perform organ-specific functions after being serially cultured for prolonged periods. These strains include steroid-secreting Leydig cells, melanomacells that form pigment, and two strains from a hormone-secreting rat pituitary tumor. One of the cell lines from the pituitary tumor secretes growt hormone, while another line derived from the same tumor secretes a substance similar to adrenocorticotropic hormone.     

Daily variation in concentration of cortisol in plasma in intact and hypophysectomized gulf killifish

A daily variation in concentration of cortisol in plasma is synchronized by a 12-hour daily photoperiod in intact as well as in hypophysectomized fish. The daily rhythm in concentration of the adrenal steroid does not depend on a daily rhythm in the concentration of pituitary adrenocorticotropic hormone.     

Inhibition of aldosterone production by an atrial extract

Crude extracts of rat atria reduced the basal amount of aldosterone released from rat zona glomerulosa cells and partially inhibited aldosterone stimulation by adrenocorticotropic hormone and angiotensin II. The destruction of this activity by trypsin suggests that the active factor is a peptide, possibly atrial natriuretic factor. These data suggest that atrial natriuretic factor affects sodium excretion by the kidneys both directly and through the inhibition of aldosterone production.     

Inhibition of adrenocorticotropic hormone secretion in the rat by immunoneutralization of corticotropin-releasing factor

Intravenous administration of rabbit antiserum to ovine corticotropin-releasing factor (CRF) markedly reduced the CRF-induced rise of plasma adrenocorticotropic hormone (ACTH) in intact nonstressed adult male rats while blocking more than 75 percent of the ACTH release observed in rats exposed to ether stress. Furthermore, antiserum to CRF significantly lowered ACTH levels in adrenalectomized animals. These results suggest that endogenous CRF plays a physiological role in regulating ACTH secretion.     

Release of multiple hormones by a direct action of interleukin-1 on pituitary cells

Exposure to bacterial endotoxins has long been known to stimulate the release of anterior pituitary hormones; administration of endotoxin was at one time a common clinical test of anterior pituitary function. Endotoxin is a potent stimulus for production of the endogenous pyrogenic protein, interleukin-1 (IL-1), by macrophages and monocytes. The possibility that IL-1 has a direct effect on the secretion of hormones by rat pituitary cells in a monolayer culture was investigated. Recombinant human IL-1 beta stimulated the secretion of adrenocorticotropic hormone, luteinizing hormone, growth hormone, and thyroid-stimulating hormone. Increased hormone secretion into culture supernatants was found with IL-1 concentrations ranging from 10(-9) M to 10(-12) M. Prolactin secretion by the monolayers was inhibited by similar doses. These concentrations of IL-1 are within the range reported for IL-1 in serum, suggesting that IL-1 generated peripherally by mononuclear immune cells may act directly on anterior pituitary cells to modulate hormone secretion in vivo. Incubation of IL-1 solutions with antibody to IL-1 neutralized these actions. These pituitary effects of IL-1 suggest that this monokine may be an important regulator of the metabolic adaptations to infectious stressors.     

Radioreceptor assay of adrenocorticotropic hormone: new approach to assay of polypeptide hormones in plasma

Biologically active iodine-125-labeled adrenocorticotropic hormone (ACTH) binds specifically to ACTH receptors extracted from adrenals. Unlabeled ACTH at 1 picogram per milliliter significantly displaces labeled ACTH from these receptors. This system, which appears to be applicable to all polypeptide hormones, provides a rapid and sensitive method for measurements of biologically active ACTH in dilute whole plasma.     

Normalizing effect of an adrenocorticotropic hormone (4-9) analog ORG 2766 on disturbed social behavior in rats

Short-term isolation increased the frequency of social interactions in rats tested in pairs, while pairs of rats placed in an unfamiliar test cage and subjected to a high level of illumination spent less time in active social contact. These changes in social behavior elicited by environmental manipulations were counteracted by treatment with the adrenocorticotropic hormone (4-9) analog ORG 2766. The peptide's normalizing effect may be mediated by endogenous opioid systems.     

Divergent biological effects of adenosine and dibutyryl adenosine 3',5'-monophosphate on the isolated fat cell

Adenosine 3',5'-monophosphate stimulated production of carbon dioxide and lipid from glucose, whereas its dibutyryl derivative inhibited this conversion. Addition of the dibutyryl derivative to the isolated fat cell further stimulated lipolysis induced by adrenocorticotropic hormone, whereas addition of adenosine 3',5'-monophosphate inhibited this lipolysis. Hence, measured by these two parameters, the biologic properties of adenosine 3',5'-monophosphate and its dibutyryl derivative are distinctly different.     

Adenosine 3',5'-monophosphate, adrenocorticotropic hormone, and adrenocortical cytosol protein synthesis

In cultures of mouse adrenocortical tumor cells (Sato's minimal deviation Y-1 clonal strain), the acceleration of steroid biosynthesis after exposure to adrenocorticotropic hormone or cyclic adenosine 3',5'-monophosphate is maximum within 15 to 60 minutes and precedes any significant increase in labeling of protein with [4,5-(3)H]leucine. However, when cytosol proteins are separated by acrylamidegel electrophoresis, rapid changes in the amount and labeling of several protein fractions are evident in less than 30 minutes and are no longer evident within 60 minutes. This finding supports the proposal that the effects of tropic hormones and their intracellular mediators involve rapid selective effects on protein synthesis.     

Corticotropin-releasing activity of monokines

Hepatocyte-stimulating factor and interleukin-1 are proteins produced by monocytes in response to inflammatory challenge. Neither of these monokines had direct effects on steroid production by cultured adrenocortical cells. Both monokines stimulated pituitary cells (AtT-20) to release adrenocorticotropic hormone; interleukin-1 was equipotent with a combination of corticotropin-releasing factor and arginine vasopressin, and hepatocyte-stimulating factor was at least three times as effective. The synthetic glucocorticoid, dexamethasone, inhibited production of hepatocyte-stimulating factor by cultured monocytes. These results indicate an axis between monocytes and pituitary and adrenocortical cells which may play a role in regulating host defense.     

板栗子房内源激素含量与空苞形成关系的研究

采艇控制授粉方法分析了板栗授粉前后子房内源激素含量的变化。结果表明,授粉刺激了板栗子房内源ＧＡ１／３、ｉＰＡ８含量及（ＧＡ１／３＋ｉＰＡｓ）／ＡＢＡ值增加,并降低了子房内源ＡＢＡ含量。未授粉子房和正常授粉子房在授粉前后内源激素含量及变化趋势上的差异,与空苞栗子房和正常栗子房间同一时期的差异基本相似,且未授粉子房内激激素含量变化与空苞栗一致,因此可认为板栗子房授粉不良是空苞形成的重要原因。     

Corticotropin-releasing factor-producing neurons in the rat activated by interleukin-1

Intraperitoneal administration of human recombinant interleukin-1 (IL-1) to rats can increase blood levels of corticosterone and adrenocorticotropic hormone (ACTH). The route by which IL-1 affects pituitary-adrenal activity is unknown. That the IL-1-induced pituitary-adrenal activation involves an increased secretion of corticotropin-releasing factor (CRF) is indicated by three lines of evidence. First, immunoneutralization of CRF markedly attenuated the IL-1-induced increase of ACTH blood levels. Second, after blockade of fast axonal transport in hypothalamic neurons by colchicine, IL-1 administration decreased the CRF immunostaining in the median eminence, indicating an enhanced release of CRF in response to IL-1. Third, IL-1 did not stimulate ACTH release from primary cultures of anterior pituitary cells. These data further support the notion of the existence of an immunoregulatory feedback circuit between the immune system and the brain.     

日本海马（Hippocampus japonicus）仔鱼期脑垂体发育的组织学研究

本文研究了日本海马（Ｈｉｐｐｏｃａｍｐｕｓｊａｐｏｎｉｃｕｓ）仔鱼期脑垂体形态变化和激素分泌细胞的分化。１日龄仔鱼脑垂体的形态已建成，属于前后型，类同于海马成体脑垂体。腺垂体内各种激素分泌细胞均未分化，根据细胞大小和排列方式可区分出ＲＰＤ、ＰＰＤ和ＰＩ三个区域。神经垂体只见于ＲＰＤ和ＰＰＤ交界的背上方。５日齿仔鱼腺垂体内ＧＨ细胞已分化，占ＰＰＤ的２／３，其他激素分泌细胞未见分化。１０日龄仔鱼脑垂体内除ＧＨ细胞外，未见其他种类激素分泌细胞分化。１５日龄仔鱼脑垂体ＲＰＤ内ＡＣＴＨ细胞已分化，ＰＰＤ和ＰＩ内除ＧＨ细胞外，其他种类激素分泌细胞均未分化。３０日龄仔鱼ＲＰＤ、ＰＰＤ和ＰＩ内各种激素分泌细胞都已分化，共有６种激素分泌细胞，分别是促肾上腺皮质激素（ＡＣＴＨ）分泌细胞，催乳激素（ＰＲＬ）分泌细胞，生长激素（ＧＨ）分泌细胞、促甲状腺激素（ＴＳＨ）分泌细胞、促性腺激素（ＧＴＨ）分泌细胞和促黑激素（ＭＳＨ）分泌细胞。