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R S Yalow

Publications and source records attributed to R S Yalow.

At least 19 recordsLinked to original sources
PubMed1992

Isolation and amino acid sequences of opossum vasoactive intestinal polypeptide and cholecystokinin octapeptide.

Evolutionary history suggests that the marsupials entered South America from North America about 75 million years ago and subsequently dispersed into Australia before the separation between South America and Antarctica-Australia. A question of interest is whether marsupial peptides resemble the corresponding peptides of Old or New World mammals. Previous studies had shown that "little" gastrin of the North American marsupial, the opossum, is identical in length to that of the New World mammals, the guinea pig and chinchilla. In this report, we demonstrate that opossum cholecystokinin octapeptide, like that of the Australian marsupials, the Eastern quoll and the Tamar wallaby, is identical to the cholecystokinin octapeptide of Old World mammals and differs from that of the guinea pig and chinchilla. However, opossum vasoactive intestinal polypeptide differs from the usual Old World mammalian vasoactive intestinal polypeptide in five sites: [sequence; see text].

Amino Acid Sequence↗
PubMed1991

Rhesus monkey gastroenteropancreatic hormones: relationship to human sequences.

The amino acid sequences of the gastroenteropancreatic peptides of Old World mammals are generally well-conserved. However, only the glucagons and vasoactive intestinal polypeptides (VIP) have been shown to be identical among the species studied to date. Rhesus monkey (Macaca mulatta) insulin has been shown to be identical with human insulin. The question addressed in this study is whether other gastroenteropancreatic peptides are identical to the human peptides. Purification and sequencing of glucagon, pancreatic polypeptide, VIP and insulin confirmed their identity with the corresponding human peptides. However, the 17 amino acid monkey gastrin is identical to dog gastrin and differs from human gastrin by substitution of methionine for leucine at position 5 from the N-terminus and alanine for glutamic acid in position 10. If additional rhesus monkey tissues become available, it would be of interest to determine whether other gastrointestinal peptides also differ from the corresponding human peptides.

Amino Acid Sequence↗
PubMed1990

Purification of bovine cholecystokinin-58 and sequencing of its N-terminus.

Molecular cloning of cholecystokinin (CCK) mRNA from porcine brain and gut has demonstrated that CCK is synthesized as an identical precursor in both tissues. The sequence for porcine CCK-58 predicted from CCK cDNA was identical with the amino acid sequence of the peptide purified from different lots of animals. However one group did report that there were differences in the N-terminus of CCK-58 purified from the intestines of two different lots of mongrel dogs. In the current report it is demonstrated that the amino acid sequences of CCK-58 purified separately from three bovine brains are identical through the first 19 N-terminal amino acid residues. The peptides were sequenced for ten additional steps and were shown to be identical with the previously reported sequences for the N-terminus of CCK-39. The N-terminus of bovine CCK-58 has the following sequence: AVPRVDDEPRAQLGALLAR.

Amino Acid Sequence↗
PubMed1990

Opossum (Didelphis virginiana) "little" and "big" gastrins.

1. "Little" gastrins from most mammalian species are 17 amino acid peptides and the precursor "big" gastrins are 34 amino acid peptides. 2. "Little" gastrins of the New World hystricomorphs, guinea-pig and chinchilla, are 16 amino acid peptides due to deletion of a glutamic acid in the region 6-9 from their NH2-terminus and the corresponding "big" gastrins are 33 amino acid peptides. 3. Antral gastrins from the opossum, a New World marsupial, have a glutamic acid deletion in the same region as the hystricomorph gastrins. 4. Opossum "big" gastrin is a 33 amino acid peptide with the following sequence: less than ELGPQDLPYLTADLSKKQGPWLEEEEAYGWMDF#.

Amino Acid Sequence↗
PubMed1990

Isolation and amino acid sequences of squirrel monkey (Saimiri sciurea) insulin and glucagon.

It was reported two decades ago that insulin was not detectable in the glucose-stimulated state in Saimiri sciurea, the New World squirrel monkey, by a radioimmunoassay system developed with guinea pig anti-pork insulin antibody and labeled pork insulin. With the same system, reasonable levels were observed in rhesus monkeys and chimpanzees. This suggested that New World monkeys, like the New World hystricomorph rodents such as the guinea pig and the coypu, might have insulins whose sequences differ markedly from those of Old World mammals. In this report we describe the purification and amino acid sequences of squirrel monkey insulin and glucagon. We demonstrate that the substitutions at B29, B27, A2, A4, and A17 of squirrel monkey insulin are identical with those previously found in another New World primate, the owl monkey (Aotus trivirgatus). The immunologic cross-reactivity of this insulin in our immunoassay system is only a few percent of that of human insulin. Squirrel monkey glucagon is identical with the usual glucagon found in Old World mammals, which predicts that the glucagons of other New World monkeys would not differ from the usual Old World mammalian glucagon. It appears that the peptides of the New World monkeys have diverged less from those of the Old World mammals than have those of the New World hystricomorph rodents. The striking improvements in peptide purification and sequencing have the potential for adding new information concerning the evolutionary divergence of species.

Amino Acid Sequence↗
PubMed1989

Cholecystokinin and vasoactive intestinal peptide in brain and gut of the hypothyroid neonatal rat.

The rat has been a useful model for studying neuronal and metabolic abnormalities associated with fetal and neonatal hypothyroidism produced by treatment of the mother with antithyroid medication. The neonates are then maintained on this medication via the mother's milk until weaning and subsequently through the drinking water. We have determined the concentrations and contents of immunoreactive cholecystokinin (CCK) and vasoactive intestinal peptide (VIP) in the brain and gut of groups of rats exposed to antithyroid medication from day 16 of gestation. The neonates were sacrificed at 2, 4, 8 and 12 weeks. Compared to controls total body weight was greatly reduced in methimazole (MMI)-treated rats, all of whom were hypothyroid as evidenced by marked reduction of T4 and increase in TSH. Discontinuation of MMI-treatment after 8 weeks resulted in normalization of T4 and TSH and a dramatic weight gain but at 12 weeks the brain weights of the MMI-treated rats were reduced by 17% and the brain contents, of CCK and VIP were similarly reduced. Tissue weights throughout the gut were 1/2 or less than those of control rats. Since VIP but not CCK concentrations in the gut of MMI-treated animals were significantly greater than those of the control animals, it would appear that there was greater loss of mucosal tissue with its endocrine content of CCK than of neuronal tissue with its greater content of VIP.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1988

Hyperinsulinemia.

Patients with mild or early non-insulin-dependent diabetes mellitus often display a delay in insulin response followed by late hyperinsulinemia during oral glucose tolerance testing. Those patients with long-standing disease or elevations of fasting plasma glucose in excess of 140 mg/dl are generally hypoinsulinemic in response to an oral glucose tolerance test. Diabetic patients who do not have an acute response to intravenous glucose may have normal responses to intravenous tolbutamide or intravenous arginine, suggesting that delayed responsiveness to glucose is not due to decreased pancreatic insulin content. An association between hyperinsulinemia and hypertension has been suggested by recent studies from several laboratories. In a homogeneous population of men who suffered traumatic bilateral above-the-knee amputation in the Vietnam War with subsequent development of obesity, it was shown that there was strong correlation between hypertension and hyperinsulinemia during oral glucose tolerance testing despite only mild glucose intolerance. In addition, a subset of hypertensive women who were in their third trimester of pregnancy were markedly hyperinsulinemic during oral glucose tolerance testing in the absence of any abnormalities of glucose tolerance. Thus, the relationship between hyperinsulinemia and hypertension, and the possible reasons for this relationship, are fields of active investigation at present.

Acute Disease↗
PubMed1988

Immunoreactive glucagons purified from dog pancreas, stomach and ileum.

Previous studies have shown that pig intestine contains a 69 amino acid glucagon (glicentin) as well as a 37 amino acid glucagon (oxyntomodulin). In pig pancreas the 29 amino acid glucagon predominates. Since glucagon is thought to be expressed from a single gene in mammals, these differences in molecular forms indicate differential posttranslational processing of the glucagon precursor by different tissues. In the current study glucagon immunoreactivity (IR) was separately purified from dog pancreas, stomach mucosa and ileum mucosa. Purification and sequence analysis of the different tissue glucagons show that dog pancreas and stomach mucosa contain glucagon-29 while ileum mucosa contains glucagon-37 and glucagon-69. The latter is the major form present with glucagon-37 accounting for only 10-20% of the total ileum glucagon content. The N-terminal 32 amino acid portion of dog glucagon-69 differs at 6 sites from pig glucagon-69: RSLQDTEEKSRSFSAPQTEPLNDLDQMNEDKR... The C-terminal glucagon-37 is identical to pig oxyntomodulin.

Amino Acid Sequence↗
PubMed1987

Dog secretin: sequence and biologic activity.

Secretin was purified from the first 50 cm of proximal intestine of a single dog. The purification sequence included extraction in acid-ethanol, differential precipitation with acetone, Sephadex gel filtration and three successive HPLC steps. Dog secretin has the following sequence: HSDGTFTSELSRLRESARLQRLLQGLV. The underlined amino acid represents a substitution of Glu for Asp at position 15 from the NH2-terminus of pig secretin. Dog secretin is equal in potency to pig secretin in stimulating pancreatic ductal flow in a rat bioassay system.

Amino Acid Sequence↗
PubMed1987

Chinchilla "big" and "little" gastrins.

Gastrin heptadecapeptides (gastrins I and II which differ in the presence of sulfate on the tyrosine of the latter) have been purified and sequenced from several mammalian species including pig, dog, cat, sheep, cow, human and rat. A 34 amino acid precursor ("big" gastrin), generally accounting for only 5% of total gastrin immunoreactivity, has been purified and sequenced only from the pig, human, dog and goat. Recently we have demonstrated that guinea pig (GP) "little" gastrin is a hexadecapeptide due to a deletion of a glutamic acid in the region 6-9 from its NH2-terminus and that GP "big" gastrin is a 33 amino acid peptide. The chinchilla, like the GP, is a New World hystricomorph. This report describes the extraction and purification of "little" and "big" gastrins from 31 chinchilla antra. Chinchilla "little" gastrin is a hexadecapeptide with a sequence identical to that of the GP and its "big" gastrin is a 33 amino acid peptide with the following sequence: (See text)

Amino Acid Sequence↗
PubMed1987

Cholecystokinin octapeptides purified from chinchilla and chicken brains.

Cholecystokinin octapeptides (CCK8's) have been purified from methanol extracts of 30 chinchilla and 50 chicken brains containing 9.3 nmol and 8.5 nmol of the peptides respectively. Immunoreactive CCK was concentrated on a DEAE trisacryl column and purification effected by two successive HPLC steps. The peptides were each shown to have a sulfated tyrosine. The sequences of the two peptides are compared with the corresponding CCK8's of pig and guinea pig (GP). Chinchilla & GP: D Y V G W M D F; Chicken & pig: D Y M G W M D F. Since chinchilla insulin resembles other mammalian insulins more than does GP insulin, it is of particular interest that the CCK8's of these two species are identical and raises the question as to whether other brain-gut peptides of the chinchilla, which is a New World mammal as is the GP, would resemble those of the GP or the corresponding peptides of Old World mammals.

Amino Acid Sequence↗
PubMed1987

Chicken glucagon: sequence and potency in receptor assay.

Glucagon is a 29 amino acid peptide that is generally highly conserved. Among mammalian glucagons the only one that has been shown to differ significantly is that of the guinea pig which differs from the others in 5 of the 9 COOH-terminus amino acids. The amino acid content and partial sequencing of chicken glucagon had been reported earlier. This report describes the purification and complete amino acid sequencing of chicken glucagon and demonstrates that it differs from the usual mammalian glucagon by the replacement of asparagine at position 28 with serine. Chicken glucagon is indistinguishable from porcine glucagon in the rat liver receptor assay system.

Amino Acid Sequence↗
PubMed1987

Brain/gut peptides in fed and fasted rats.

The concentrations and contents of vasoactive intestinal peptide (VIP) and cholecystokinin (CCK) in the brain and of these peptides along with secretin and glucagon-like immunoreactivity (GLI) in the gut were compared in a group of 16 5-day fasted adult Sprague-Dawley rats with the corresponding peptides in a group of 16 nonfasted littermates. The mean weight of the fasted rats at the beginning of the study was 263 +/- 10 g (+/- SEM) and was 177 +/- 7 g before killing, for a net loss of 33% of initial body weight; the 16 fed rats increased their mean weight from 225 +/- 11 to 284 +/- 12 g, for a net gain of 12%. During the 5-day fast there was no change in the weight of the cortex, hypothalamus, or brain stem. However, the weight of tissues from the gut decreased to about half the weight of the corresponding tissues in the fed animals. There was no significant change in brain VIP or CCK. VIP content in the gut was unchanged. However, because of the decrease in organ weight, its concentration almost doubled. Secretin concentrations in the gut of fasted rats did not change significantly, but organ contents fell to about half. The gut content of GLI also fell by half or more. The concentrations of CCK in methanol extracts of the duodenum and jejunum remained relatively constant, but those in acid extracts fell by 40% in the fasted animals. This represents an approximately 70% decrease in organ content of CCK. These findings are interpretable as demonstrating that during a prolonged fast neuronal CCK and VIP are well conserved, but endocrine CCK, secretin, and GLI are markedly decreased because of loss of intestinal mucosa.

Animals↗