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J M Terris

Publications and source records attributed to J M Terris.

14 recordsLinked to original sources
PubMed2001

UT-A3: localization and characterization of an additional urea transporter isoform in the IMCD.

UT-A3 has recently been identified as a splicing variant transcript of the UT-A gene present in the kidney. To study the cellular and subcellular localization of UT-A3, we raised a new polyclonal antibody to its COOH-terminal end. Immunoblots identified bands at 44 and 67 kDa predominately in the inner medulla and showed that the antibody does not recognize UT-A1. Deglycosylation with PNGase decreased the molecular mass of both forms to 40 kDa. UT-A3 is most abundant in the inner third of the inner medulla and is present in membrane fractions. Cell fractionation studies showed that UT-A3 is only detectable in inner medullary collecting duct (IMCD) cells. These observations were confirmed with immunolocalization studies demonstrating an exclusive labeling of IMCD cells. Double-labeling studies with anti-Na-K-ATPase demonstrated UT-A3 in intracellular membranes and in the apical region but were incompatible with a basolateral site for UT-A3. Although the function of this isoform in the inner medulla is unknown, the large abundance suggests that it may be important in the renal handling of urea.

Animals↗
PubMed2001

97- and 117-kDa forms of collecting duct urea transporter UT-A1 are due to different states of glycosylation.

UT-A1 is an extremely hydrophobic 929-amino acid integral membrane protein, expressed in the renal inner medullary collecting duct, with a central role in the urinary concentrating mechanism. Previous immunoblotting studies in rats have revealed that UT-A1 is present in kidney in 97- and 117-kDa monomeric forms and that the relative abundance of the two forms is altered by vasopressin treatment and other treatments that altered urinary inner medullary urea concentration. The present studies were carried out using protein chemistry techniques to determine the origin of the two forms. Peptide-directed polyclonal antibodies targeted to five sites along the polypeptide sequence from the NH2 to the COOH terminus labeled both forms, thus failing to demonstrate a significant deletion in the primary amino acid chain. The 97- and 117-kDa monomeric forms were both reduced to 88 kDa by deglycosylation with N-glycosidase F, indicating that a single polypeptide chain is glycosylated to two different extents. Studies using nonionic detergents for membrane solubilization or using homobifunctional cross-linkers demonstrated that UT-A1 exists as a 206-kDa protein complex in native kidney membranes. The mobility of this complex was also increased by deglycosylation. Both the 97- and 117-kDa proteins, as well as the 206-kDa complex, were immunoprecipitated with UT-A1 antibodies. We conclude that UT-A1 is a glycoprotein and that the two monomeric forms (97 and 117 kDa) in inner medullary collecting duct are the consequence of different states of glycosylation.

Animals↗
PubMed1996

Quantitation of aquaporin-2 abundance in microdissected collecting ducts: axial distribution and control by AVP.

Aquaporin-2 (AQP-2) is the arginine vasopressin-regulated water channel of the renal collecting ducts. Using an improved version of a fluorescence-based enzyme-linked immunosorbent assay (Y. Maeda, B. L. Smith, P. Agre, and M. A. Knepper. J. Clin. Invest. 95: 422-428, 1995), we quantified AQP-2 protein abundance in microdissected renal collecting ducts from normal Sprague-Dawley (SD) rats and vasopressin-deficient Brattleboro rats. Standard curves were linear in the range of 0-200 fmol/well and were highly reproducible from day to day (lower limit of detection 2.3 fmol; coefficient of variation 6-9%). In SD rats thirsted for 24 h, the measured quantities of AQP-2 were as follows (x 10(9) molecules/mm): cortical collecting ducts (CCD), 4.3 +/- 0.5; outer medullary collecting ducts (OMCD), 10.1 +/- 1.7; initial one-third of inner medullary collecting duct (IMCD-1), 9.2 +/- 1.1; middle one-third of the IMCD (IMCD-2), 7.5 +/- 0.8; terminal one-third of the IMCD (IMCD-3), 3.3 +/- 0.6; n = 7-12. In IMCD-2 this corresponds to 11.8 +/- 1.3 x 10(6) AQP-2 molecules per cell. Thus AQP-2 is extremely abundant in collecting duct cells. AQP-2 levels were decreased in untreated Brattleboro rats relative to the parent strain Long-Evans (LE) by 68% in IMCD-2 and 44% in CCD. Following vasopressin infusion by osmotic minipumps, AQP-2 levels in IMCD-2 of Brattleboro rats rose gradually, reaching levels equivalent to those seen in LE rats after 5 days. A similar rise was seen in the CCD, indicating that the vasopressin-induced increase was not dependent on a large increase in the interstitial tonicity. Thus a rise in circulating vasopressin concentration increases the level of AQP-2 protein expression in collecting ducts, presumably via a direct action of vasopressin.

Animals↗
PubMed1990

Renal physiology of the pig: application of stop-flow.

1. The stop-flow method in the pig, with modified kidneys, produced patterns for sodium, chloride, glucose and PAH that were similar to those obtained previously in other animals with simple kidneys. 2. Ethacrynic acid, under the conditions of the experiment, abolished distal sodium and chloride reabsorption in the pig. 3. We conclude that this method, viewed in perspective, could provide useful in situ information about the physiology of modified kidneys where the more difficult micropuncture and in vitro perfusion techniques are impractical.

Animals↗
PubMed1990

Relationship of hypokalemia to metabolic alkalosis in the intact Yucatan miniature boar following implantation of deoxycorticosterone-acetate (DOCA) or d-aldosterone.

1. Normo-kalemic Yucatan miniature boars were implanted with deoxycorticosterone-acetate (DOCA) or d-aldosterone (Aldo) to evaluate the relationship of hypokalemia to the pathogenesis of metabolic alkalosis following mineralocorticoid administration. 2. Serum potassium was significantly less than control within 24 hr, serum bicarbonate significantly elevated within 4 days and pH 1-2 days later with no significant differences between DOCA and Aldo. 3. These data demonstrate that pre-existing potassium deficits are not required for the development of alkalosis with mineralocorticoid administration, DOCA and Aldo are equally effective, co-existing hypokalemia is necessary in the genesis, and perhaps maintenance, of metabolic alkalosis with excess mineralocorticoids, and hypokalemia is not a consequence of the alkalosis.

Aldosterone↗
PubMed1984

A diabetes insipidus-like syndrome in the intact Yucatan miniature boar following implantation of desoxycorticosterone-acetate (DOCA).

A syndrome of polydipsia and polyuria is described in the intact adult Yucatan miniature boar following implantation of silicone rubber strips impregnated with desoxycorticosterone-acetate (DOCA). Water intake was significantly greater than control 5 days post-DOCA. Urine output was significantly greater than control 7 days post-DOCA, and urine osmolality was significantly decreased 8 days post-DOCA. Serum potassium was significantly less than control 24 hr post-DOCA, and serum sodium was consistently and significantly greater than control by 1 week post-DOCA. As suggested in the dog, the increase in water turnover following DOCA administration in the pig is initiated by an increased thirst followed by an increase in urine output.

Animals↗
PubMed1983

Effect of chronic guanethidine treatment on vascular norepinephrine content in the neonatal domestic pig.

Vinblastine, 6-hydroxydopamine, and antibody to nerve growth factor have been shown to destroy sympathetic neurons in neonatal rats. High doses of guanethidine produce permanent sympathectomies in the adult or newborn rat. Similar studies in the cat, rabbit, and hamster demonstrate that the sympathetic nervous systems are not destroyed with guanethidine. To produce permanent sympathectomy in a large animal model, guanethidine was administered to neonatal pigs. As with the cat, rabbit, and hamster, the sympathetic nervous system in the piglets was not destroyed by guanethidine.

Animals↗
PubMed1983

Metabolic alkalosis in the Yucatan miniature boar following desoxycorticosterone-acetate (DOCA) implantation.

Metabolic alkalosis was induced in adult Yucatan miniature boars by subcutaneous implantation of desoxycorticosterone-acetate impregnated silicone rubber strips. Serum pH, bicarbonate, and PaCO2 increased rapidly and consistently following implantation. As in the dog and the rat, hypokalemia was accompanied by hypochloremia. As in the rabbit, hypokalemia developed in the presence of a decreased urinary output of potassium and apparent absence of kaliuresis. The pig is resistant to the paralytic effects of hypokalemia. Implantation of DOCA is an effective means of producing chronic metabolic alkalosis in the pig which is characterized by hypokalemia and hypochloremia.

Alkalosis↗
PubMed1982

A portable confinement unit for swine.

A confinement unit was developed for use with miniature swine (45-140 Kg) for procedures which required restriction of movement without total immobilization. The light-weight unit was constructed largely of aluminum. It could be moved by one person, and it was easy to clean. Provision also was made for the collection of urine and feces from animals involved in metabolic studies. Ramps at both ends of the unit insured easy entry and exit of the animals and prevented unnecessary stress. A detachable side panel facilitated the removal of animals under anesthesia. Although intended for use with swine, these units have proven satisfactory for sheep.

Animals↗
PubMed1976

Deoxycorticosterone hypertension in the pig.

1. Deoxycorticosterone acetate (DOCA) implantation (100 mg/kg) caused mean arterial pressure to rise in 5-10 days from control pressures of 100-115 mmHg to stable hypertensive values of 140-160 mmHg in approximately 1 month. In six of seven pigs elevations of mean arterial pressure were entirely the result of increased total peripheral resistance. 2. Single implants maintained serum DOCA at approximately ten times normal concentration for up to 90 days. 3. Moderate but variable decreases in serum aldosterone followed implantation. 4. Hypokalaemia, polydipsia and suppressed plasma renin activity were evident by the fifth post-implantation day and persisted thereafter. No consistent change occurred in serum sodium. 5. Noradrenaline or angiotensin caused increases in total peripheral resistance at lower threshold infusion rates in hypertensive pigs compared with control animals. 6. In isolated, perfused hind-limb preparations, hypertensive vascular beds were characterized by both functional (increased vascular smooth muscle sensitivity) and structural (elevated resistance of maximally dilated vascular bed) changes. 'Protection' from increased arterial wall stresses in hypertensive pigs prevented structural, but not functional, alterations.

Angiotensin II↗
PubMedDate not supplied

Hemodynamic responses to DOCA in young pigs.

Hemodynamic variables were measured in 20 young pigs; thirteen received subcutaneous implantations of desoxycorticosterone acetate (DOCA) impregnated in Silastic strips, seven received implants of Silastic strips alone and served as controls. No salt was added to the standard diet of either group. Mean arterial pressure (MAP) rose in a regular pattern in the DOCA-treated pigs, reaching on the average a level significantly greater than that of the control group 48 hours after the implantation. Pressure continued to rise, reaching a plateau 38% above that of the preimplant value 2 weeks later. In some pigs the MAP elevation was caused by an increase in cardiac output (CO); in others it was caused by an increase in total peripheral resistance (TPR). An increase in central venous pressure occurred in many DOCA-treated pigs regardless of whether the increase in MAP was caused by an increase in CO or in TPR. The results indicate that it is arterial pressure per se that is the regulated variable in this model of mineralocorticoid hypertension. The regulating system, whether it resides in the kidney or in the central nervous system, elevates pressure by effecting increases in either CO or TPR.

Animals↗
PubMedDate not supplied

Electrolyte and hormonal effects of deoxycorticosterone acetate in young pigs.

Balances of sodium, potassium, and water were studied in the growing male pig as hypertension developed in response to subcutaneous implantation of deoxycorticosterone acetate (DOCA). Serum sodium, potassium, deoxycorticosterone (DOC), aldosterone, and plasma renin activity (PRA) were determined. These variables were observed in a total of 10 experimental and nine control pigs. All animals were uninephrectomized and fed a diet of Purina Pig Chow and tap water ad libitum. No salt was added to the food or water. Serum DOC levels rose dramatically on the day of the implantation, then gradually declined but remained approximately 10 times greater than control levels 40 days after implant. Plasma renin activity was suppressed rapidly and completely, whereas aldosterone fell only slowly to about half its control value. Sodium retention was maximum during the first 24 hours. Therefore an "escape" process became operative, causing sodium balance to return to normal after the third day, at which time the major rise in arterial pressure occurred. A marked increase in water turnover (intake and output) also began after the third day and persisted throughout the experimental period. Water balance remained normal during this period of increased turnover. Hypokalemia developed in the absence of kaliuresis, suggesting that potassium moved into the cells. Except for the potassium retention, these changes parallel the abnormalities seen in other states of mineralocorticoid excess.

Animals↗