The combination of lutropin (LH; luteinizing hormone) a and 13 subunits was examined in rat pituitaries incubated with [3S]methionine or [3S]sulfate. Combination was assessed by using antiserum directed against the 18 subunit. The data show that combination of most of the subuniits proceeds rapidly, well before the addition of sulfate and prior to the processing of asparagine-linked oligosaccharides to the complex form. Thus, combination appears to initiate in the endoplasmic reticulum and does not require those post~translational modifications. We observed that two forms of the LH-a subunit were processed-one that is secreted into the medium not associated with the LH (3 subunit and another secreted as part of the a-13 dimer. Both forms ofthe a subunit are sulfated, and the data suggest that subsequent to sulfate addition, secretion offree a subunit and the dimer occur independently by separate pathways.The pituitary hormones lutropin (LH), follitropin (FSH), and thyrotropin (TSH) are members ofa family ofstructurally similar glycoproteins that includes the placental hormone, human choriogonadotropin (hCG). Each hormone is composed of two dissimilar, noncovalently-associated subunits designated a and 3, which contain one or two asparagine-linked carbohydrate groups. Within a species, the amino acid sequences of the a subunits are identical, and the biological specificity of these hormones resides in their respective / subunits (1).Although the chemical structures ofthe a and P3 subunits are well characterized, only recently has information concerning the synthesis and processing ofthe subunits emerged. The subunits are translated from separate mRNAs (2-4), and high mannose oligosaccharide units are transferred to asparagine residues in the nascent chains as they cross the endoplasmic reticulum (5). After release ofthe completed subunits from the ribosomes, these oligosaccharides are processed by enzymes localized within the Golgi complex. Recent studies have detected sulfate covalently linked to oligosaccharides on the a and 3 subunits of LH and thyrotropin but not of choriogonadotropin (6,7). Thus, these hormones are subjected to several post-translational steps before they emerge from the cells.A crucial step in the production ofthese hormones is the joining ofthe subunits. The timing and location oftheir combination after synthesis has not been established, and it is not known if maturation of the oligosaccharide side chain or sulfation (or both) is required for coupling of the subunits. We have demonstrated that, in the anterior lobe of the rat pituitary, LH and thyrotropin subunits could be labeled intracellularly with F3S]sulfate and [35S]methionine (7). During this work we observed that antisera directed against the bovine LH-P subunit precipitated the intact hormone. This observation permitted us to analyze the a-P subunit combination event in cells.Here, we present evidence that the assembly ofLH subunits occurs within the first few minutes of protein synthesis, well before the mature hormone ...
Methylprednisolone or saline (placebo) solution was infused intravenously in 28 patients undergoing elective lobectomy for lung cancer. The state of the complement system during and after surgery and the effects of methylprednisolone on biologically active products of complement were studied by measurements of plasma C3a and C5a anaphylatoxins and leukocyte counts in peripheral blood perioperatively. In the placebo group plasma concentrations of C3a were significantly increased on postoperative days 1 and 2, whereas C5a had risen significantly 6 hours after surgery and on days 1 and 2. Methylprednisolone infusion during surgery eliminated the postoperative elevation of C3a and C5a. The postoperative leukocyte count in peripheral blood was higher in the methylprednisolone group than in the controls. The observations indicated that methylprednisolone may reduce the influx of leukocytes from peripheral blood into the airways by attenuating production of biologically active complements.
A calcium- and phospholipid-dependent protein kinase C subspecies purified from rat brain was inhibited by thiamylal, thiopentone, pentobarbitone, mepivacaine and bupivacaine. This was attributed to the inhibition of the activation process rather than to direct interaction with the active site of the enzyme. It is well established that unsaturated diacylglycerol markedly increases the affinity of protein kinase C for calcium ions. Kinetic analysis suggested that pentobarbitone brought about the inhibition by competing with the diacylglycerol diolein and that mepivacaine and bupivacaine competed with the phospholipid phosphatidylserine used in the assay. The possibility exists that the effects of local anaesthetics on the function of various tissues are due, in part, to an inhibitory action on protein kinase C.
The study reviews 18 infants and children with eventration of the diaphragm who were treated over a period of eight years. The affected diaphragm and pulmonary tissue were examined by light and electron microscopy. The 18 patients, ranging in age from 10 days to 6 years, were divided according to Thomas' classification into a group with the congenital (10 patients) and a group with the acquired type (8 patients). Fifteen of these patients underwent surgery with diaphragmatic plication. On microscopic examination, biopsies of the lung showed atelectasis and pneumonia. These pathological changes became increasingly diffuse and severe with age. The diaphragm in patients with the congenital type of eventration was occupied by diffuse fibroelastic tissue. In patients with the acquired type, the cross-striated muscles of the diaphragm showed degenerative changes such as fragmentation, and interstitial fibrosis of the diaphragm became prominent with age. The results of this clinical study suggest that, in order to reduce the pathological changes in the lung, early surgical plication should be performed even in patients with the acquired type, if respiratory and digestive symptoms are noted.
Intermediate lobes isolated from rat pituitary glands incorporated [35S]sulfate into pro-opiomelanocortin and other adrenocorticotropic hormone-containing peptides. Incubation of intermediate lobes in medium containing the arginine analog canavanine inhibited the cleavage of pro-opiomelanocortin into smaller products. Pro-opiomelanocortin that accumulated in the presence of canavanine was also sulfated.
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