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Biomedical subjects

J M Connors

Publications and source records attributed to J M Connors.

At least 91 records · Page 5Linked to original sources
PubMed1991

A current analysis of primary lymphoma of the thyroid.

Over a 9-year period ending in May 1990, 27 patients with histologically proved thyroid lymphoma were assessed and treated. There were 24 female and three male patients with a median age of 67 years at the time of diagnosis (age range, 39 to 85 years). The usual presentation was that of a rapidly enlarging neck mass. Incisional biopsy was the diagnostic procedure of choice; however, nine of 27 patients underwent diagnostic partial or total thyroidectomy based on a preoperative impression of thyroid carcinoma. All 27 patients had non-Hodgkin's lymphomas of intermediate (77%) or high (23%) grade. Detailed staging was carried out in 25 patients; seven patients (28%) had disease confined to the thyroid gland (stage I), while 18 (73%) had accompanying disease in cervical lymph nodes or the mediastinum (stage II). Combined multiagent chemotherapy and irradiation was given to 19 of 25 staged patients (76%). Actuarial, overall 5-year survival for all patients was 70% with 48 months being the median follow-up for living patients (follow-up range, 3 to 102 months). Of a number of factors evaluated using log-rank survival tests, only the absence of dysphagia at the time of hospital admission, a primary tumor mass not greater than 10 cm, restriction of disease to the thyroid gland, and the absence of mediastinal lymph node involvement were statistically significant predictors of improved survival. Surgery should usually be restricted to diagnostic biopsy, as there is infrequently a role for resection in the management of thyroid lymphoma, given the effectiveness of combined multiagent chemotherapy and radiotherapy.

Actuarial Analysis↗
PubMed1991

MACOP-B and VACOP-B in diffuse large cell lymphomas and MOPP/ABV in Hodgkin's disease.

Between 1981 and 1986, 126 patients with diffuse large cell lymphoma were treated with MACOP-B (methotrexate/doxorubicin/cyclophosphamide/vincristine/prednisone/bleomy cin). All had advanced-stage lymphoma (Ann Arbor stage III or IV or stage I or II if the tumor mass was greater than 10 cm or B symptoms were present). The complete response (CR) rate was 84% and the toxic death rate was 6%. Actuarial overall survival at 3 years was 67% and at 8 years 62%; the failure-free survival at 8 years was 52%. The follow-up for MACOP-B is 39 to 106 months (median 76) for living patients. A multivariate prognostic factor analysis for this group of patients identified age greater than 60 years. B symptoms, more than one extranodal site of disease, and more than three nodal sites of disease as the four significant prognostic variables. From June 1986, 108 patients were enrolled on a modification of MACOP-B called VACOP-B (etoposide/doxorubicin/cyclophosphamide/vincristine/prednisone/bleomycin ). Their CR rate was 81%, and the toxic death rate was lower, at 3%. The 60% overall survival at 3 years is not statistically significantly different from that of MACOP-B. The incidence of moderate or severe mucositis and Cushingoid changes was much lower with VACOP-B. The MOPP/ABV (mechlorethamine/vincristine/procarbazine/prednisone- doxorubicin/bleomycin/vinblastine) hybrid chemotherapy regimen for advanced-stage Hodgkin's disease was standard therapy from April 1981 to June 1988 for untreated patients aged 16 to 65. Advanced stage was defined as stages IIB, IIIB, III2A, IVA, IVB, or stages IIA or IIIA with greater than four splenic nodules or a mediastinal mass greater than one third of the transthoracic diameter.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1991

Compensatory changes in thyroid blood flow are only partially mediated by thyrotropin.

It has been shown that the compensatory growth of the thyroid gland and the compensatory increase in hormone secretion that occur after hemithyroidectomy are preceded by a dramatic increase in thyroid blood flow (BF). These alterations in the thyroid remnant may be due to the concomitant increase in plasma thyrotropin (TSH) concentrations. It has been suggested, however, that the compensatory thyroid growth may also involve a neural reflex. In this study we have investigated the role of TSH in mediating the compensatory alterations in thyroid BF and mass after subtotal thyroidectomy. Male Sprague-Dawley rats were anesthetized with ether for surgical or sham hemithyroidectomy. One-half of the hemithyroidectomized rats (HTX) received no further treatment; in the other one-half of the HTX rats (Clamp), plasma TSH levels were maintained at levels comparable with those in sham-operated animals by initiating constant thyroid hormone replacement beginning at the time of hemithyroidectomy. Plasma samples for TSH, 3,5,3'-triiodothyronine, and thyroxine radioimmunoassays were obtained 2, 7, 14, and 21 days after surgery. Thyroid BF was determined at 1, 2, and 3 wk after surgery by the reference sample version of the radioactive microsphere technique (141Ce, 15 microns diameter). Plasma TSH levels and thyroid lobe weight were significantly elevated in HTX rats but not in Clamp rats. Thyroid BF was markedly increased in HTX rats. Thyroid BF was also significantly increased in Clamp rats despite the suppression of the rise in plasma TSH concentration, but this increase was less than that in HTX rats. Neither hemithyroidectomy nor Clamp treatments had any effect on arterial blood pressure or BF to other tissues (e.g., kidney).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Muscarinic modulation of the vasodilatory effects of vasoactive intestinal peptide at the rat thyroid gland.

In the thyroid gland, vasoactive intestinal peptide (VIP) and acetylcholine (ACh) are found in nerve fibers associated with secretory cells and blood vessels. We have, therefore, initiated studies to explore the actions of and interactions between cholinergic agents and VIP in the regulation of thyroid vascular conductance (VC). Thyroid and other organ blood flows were measured using radiolabelled (141Ce) microspheres injected directly into the left cardiac ventricle of anesthetized male rats. The mean systemic arterial pressure was monitored and used in the calculation of organ VC (blood flow/arterial pressure). Plasma TSH, T3, and T4 levels before and after infusions were measured by RIA. The acute administration of ACh (3 x 10(-8) mol/100 g BW) over 4 min increased thyroid VC, whereas nicotine (10(-7) mol/100 g BW) had no such effect. Circulating TSH and thyroid-hormone levels following ACh or nicotine were not different from those in vehicle-treated animals at 20 min or 2 h after infusion. This observation suggested that ACh acts through muscarinic receptors at the thyroid gland to increase VC. In order to extend these observations and to evaluate whether VIP might exert any of its thyroidal effects on VC via muscarinic receptors, we assessed the effects of ACh, methacholine chloride (MCC), and VIP in the presence and absence of the muscarinic receptor blocker atropine. Rats were treated intravenously with saline or atropine (3 mg/kg) 20 min before intravenous infusions of vehicle, ACh (3 x 10(-8) mol/100 g BW), MCC (5 x 10(-9) mol/100 g BW), or VIP (10(-11) mol/100 g BW).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1991

Intensive chemotherapy with cyclophosphamide, carmustine, and etoposide followed by autologous bone marrow transplantation for relapsed Hodgkin's disease.

Fifty-six consecutive patients with advanced Hodgkin's disease considered incurable with further conventional chemotherapy were entered into a protocol that included high-dose cyclophosphamide (7.2 g/m2), carmustine (BCNU; 0.6 g/m2), and etoposide (VP16-213; 2.4 g/m2) (CBV) followed by autologous bone marrow transplantation (BMT). Prior combination chemotherapy had failed in all the patients, and all but five had been previously treated with both mechlorethamine, vincristine, procarbazine, and prednisone (MOPP) and doxorubicin, bleomycin, and vinblastine with or without dacarbazine (ABV[D]). Thirty-four eligible patients received short-course conventional chemotherapy and/or involved-field radiotherapy before CBV. However, formal restaging was not performed after these conventional therapies; ie, the therapies were not used to select responding patients for transplantation, and all who received such therapy subsequently received CBV and autologous marrow grafts. Forty-four patients (80%; 95% confidence interval [CI], 69% to 91%) achieved a complete response after CBV and BMT. Performance status at protocol entry and the use of conventional cytoreduction therapy before CBV correlated with response. Median follow-up is now 3.5 years (range, 2.5 to 5.0 years). Kaplan-Meier estimates for overall and event-free survival 5 years after transplant are 53% (95% CI, 37% to 67%) and 47% (95% CI, 33% to 60%), respectively. In a univariate analysis, patients with a normal performance status and those without constitutional ("B") symptoms at protocol entry had an improved overall and event-free survival. In a multivariate analysis, only a normal performance status remained significant. Disease progression occurred in 17 patients at an actuarial rate of 39% (95% CI; 26% to 56%) and occurred at previous sites of active disease in all but one patient; our analysis did not identify prognostic factors for progression. Toxic deaths, caused by either neutropenic sepsis or interstitial pneumonitis (IP), occurred in 12 patients (21%; 95% CI, 10% to 32%). CBV with autologous marrow support can produce durable remissions in a substantial number of patients with Hodgkin's disease considered incurable with conventional measures. Regimen refinements may even further improve the therapeutic index of BMT in this malignancy.

Adolescent↗
PubMed1991

Prognostic variables in patients with diffuse large-cell lymphoma treated with MACOP-B.

One hundred twenty-six patients with diffuse large-cell lymphoma were treated with methotrexate with leucovorin, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (MACOP-B) between April 1981 and June 1986. Univariate and multivariate analyses were performed using overall survival as of September 1989 as the end point. Four independent negative predictors of survival were identified: presence of B symptoms; more than two involved lymph node sites; more than one extranodal site (variables related to tumor burden), and age older than 60, a variable related to the patient's ability to tolerate treatment. Each variable contributed the same relative risk of dying and, accordingly, this simple predictive formula was developed empirically: (4-N) x 30 = the approximate percentage of chance of survival at 5 years. "N" is the number of predictive variables present. The same four predictors were also found to be significant by multivariate analysis when only those patients achieving a complete response were analyzed.

Adolescent↗
PubMed1991

Low-dose ACOP-B and VABE: weekly chemotherapy for elderly patients with advanced-stage diffuse large-cell lymphoma.

Elderly patients with advanced-stage diffuse large-cell lymphomas (DLCLs) are either excluded from or under-represented in most clinical trials of combination chemotherapy regimens because they tolerate treatment poorly and usually have a worse outcome. We report two brief weekly chemotherapy regimens designed specifically for elderly patients. Eligible patients were aged 65 to 85 years, had advanced-stage DLCL (diffuse mixed, diffuse large-cleaved or noncleaved, immunoblastic, or diffuse large-cell not otherwise specified). Advanced stage was defined as Ann Arbor stage III or IV or stage I or II with a mass greater than 10 cm or B symptoms. Low-dose doxorubicin, cyclophosphamide, vincristine, bleomycin, and prednisone (LD-ACOP-B) accrued 40 patients between March 1983 and September 1985; 65% achieved a complete response (CR), there were two toxic deaths, the actuarial failure-free survival (FFS) is 19%, disease-specific survival (DSS) 30%, and overall survival (OS) 28%, with a maximum follow-up of 6 years. The regimen of etoposide, doxorubicin, vincristine, bleomycin, and prednisone (VABE) accrued 32 patients between July 1985 and June 1987; 63% achieved a CR, there were two toxic deaths, and the actuarial FFS is 34%, DSS 45%, and OS 36%, with a maximum follow-up of 4 years. There is no difference in FFS, DSS, or OS between these two regimens. VABE caused more myelosuppression and infectious complications, although the toxic death rates were similar. We prefer LD-ACOP-B because follow-up is longer and toxicity is less.

Aged↗
PubMed1991

Thyroid vascular conductance: differential effects of elevated plasma thyrotropin (TSH) induced by treatment with thioamides or TSH-releasing hormone.

We have reported previously that thyroid gland blood flow, expressed as vascular conductance (C) per mass, is decreased at very low and increased at very high chronic plasma TSH concentrations, but is apparently unchanged over a broad range of plasma TSH concentrations encompassing normal levels. The aim of the present study was to examine the apparently very steep dose-response relationship between elevated plasma TSH and thyroid vascular C/mass. In the first series of experiments, endogenous plasma TSH concentrations were manipulated by treating male Sprague-Dawley rats (250-280 g) for 6 days as follows: 1) controls (0.5 ml saline/day, ip), 2) propylthiouracil injections (2.0 mg PTU/day, ip), 3) PTU plus partial thyroid hormone replacement (2.0 mg PTU/day and 0.3-0.9 microgram T4 plus 0.075-0.225 microgram T3/100 g.day via continuous sc infusion), or 4) TRH (9-1200 micrograms TRH/100 g.day via continuous iv infusion). The vascular C values of the thyroid gland, salivary gland, kidney, and pancreas were determined using the reference sample version of the radioactive microsphere technique. PTU treatment led to the expected hypothyroidism, increased plasma TSH concentrations (959 +/- 66 vs. 154 +/- 22 ng/dl), increased thyroid weight (9.19 +/- 0.36 vs. 4.60 +/- 0.15 mg/100 g), and increased thyroid vascular C/mass (495 +/- 51 vs. 127 +/- 20 microliters/mm Hg.g/min). PTU-treated rats receiving partial thyroid hormone replacement demonstrated a dose-related suppression of plasma TSH, thyroid weight, and thyroid vascular C. Although, TRH treatments resulted in increased plasma TSH concentrations (e.g. 1200 micrograms TRH, 706 +/- 46 ng/dl) and thyroid weight (e.g. 1200 micrograms TRH, 7.45 +/- 0.41 mg/100 g), thyroid vascular C per tissue mass was not significantly increased after any TRH treatment (e.g. 1200 micrograms TRH, 166 +/- 19 microliters/mm Hg.g/min). Thus, at similarly elevated plasma TSH concentrations, the thyroid vascular C/mass of PTU- and TRH-treated rats constituted separate populations. Both PTU- and TRH-induced thyroid growth were accompanied by similar alterations in thyroid gland morphology (i.e. increased cellular mass with little change in the total amount of colloid). To investigate the mechanisms involved, groups of rats were treated for 6 days as follows: 1) control, 2) PTU or methimazole (25 mg MMI/day, ip), 3) PTU or MMI plus thyroid hormone replacement (1.2 micrograms T4 plus 0.3 microgram T3/d.100 g), 4) TRH (12 micrograms/100 g.day), and 5) PTU or MMI, thyroid hormones, and TRH.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Intensive chemotherapy and autologous peripheral blood stem cell transplantation in a patient with persistent marrow involvement with Hodgkin's disease.

A patient with refractory Hodgkin's disease whose persistent, dense marrow infiltration precluded autologous marrow harvest underwent peripheral blood stem cell harvest followed by intensive chemotherapy and re-infusion of the peripheral blood stem cells. Complete remission was followed by relapse 6 months later and death 13 months post-transplant. However, at no time post-transplant was evidence of marrow recurrence demonstrated. This case indicates that remission can be achieved using peripheral blood stem cell transplants despite persistent marrow involvement with Hodgkin's disease.

Adult↗
PubMed1989

Adrenocorticotropin and corticosterone levels in pre-weanling spontaneously hypertensive rats.

Circulating plasma ACTH and corticosterone levels were measured in spontaneously hypertensive rats (SHR) and the corresponding, normotensive Wistar-Kyoto (WKY) strain at 10 and 20 days of age. In addition, stored levels of ACTH were measured in the pituitary glands of these animals. Circulating corticosterone levels were significantly lower, in both strains, at 10 days than at 20 days. Although the glucocorticoid was undetectable in WKY animals at 10 days, significant levels were observed in age-matched SHR. No difference in corticosterone concentrations was observed between the two strains at 20 days. Circulating ACTH levels did not reflect the values for circulating glucocorticoids. There were no significant differences in the levels of ACTH between strains or between age groups. Moreover, pituitary stores of ACTH between animals of different strains and ages were not found to be significantly different among any of the groups tested. These results demonstrate that there is a difference in circulating corticosterone levels between spontaneously hypertensive and Wistar-Kyoto rats at 10 days postnatally which is not evident just prior to weaning (20 days). This difference is not due to variations in stored or circulating ACTH. Indeed, ACTH levels are high at a time (10 days) when corticosterone is low - thus suggesting that the difference may reside within the responsiveness of the adrenal cortex.

Adrenocorticotropic Hormone↗
PubMed1989

Allogeneic marrow transplantation for refractory Hodgkin's disease.

Eight patients with refractory Hodgkin's disease received intensive combination chemotherapy conditioning with cyclophosphamide, carmustine (BCNU), and etoposide (VP 16-213), and allogeneic marrow transplants. All patients achieved complete responses. Three patients relapsed; two died of Hodgkin's disease and one of chronic graft-v-host disease (GVHD) and infection. In all, four patients died due to transplant-related toxicity. One patient developed a fatal B-cell lymphoproliferative disorder soon after transplantation, and died without evidence of Hodgkin's disease. One patient is alive and free of progression 29 months after transplantation. These data indicate that allogeneic marrow transplantation may be considered as therapy for selected patients with advanced Hodgkin's disease and, despite substantial toxicity, will occasionally result in long-term responses. Better patient selection would likely improve results.

Adolescent↗
PubMed1989

Long-term follow-up and analysis for prognostic factors for patients with limited-stage diffuse large-cell lymphoma treated with initial chemotherapy with or without adjuvant radiotherapy.

In order to assess long-term outcome of patients with localized (stage I or II) diffuse large-cell lymphoma treated with initial combination chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) with or without involved-field radiotherapy following chemotherapy, we combined data from two prospective trials in Tucson (64 patients) and Vancouver (78 patients). Follow-up on 142 patients was updated and a variety of potential pretreatment prognostic factors were analyzed for impact on outcome. One hundred forty patients (99%) achieved a complete remission and there were no differences in outcome between institutions. Twenty-three patients have relapsed and 22 have died from lymphoma at a median follow-up of 4.4 years, resulting in an overall relapse-free survival of 82% at 5 years. There was no treatment-related mortality and were no instances of late cardiac toxicity or leukemia. Of the following potential pretreatment prognostic factors (age, stage, "B" symptoms, extranodal disease, gastrointestinal tract involvement, bulky disease, or disease above or below the diaphragm), only stage affected relapse-free survival (RFS) (P = .16) and survival (.003). Among 34% of patients over age 65, outcome was similar to younger patients. RFS for 108 patients treated with CHOP plus radiotherapy was not significantly superior to the use of CHOP alone in 34 patients (P = .2).

Adult↗
PubMed1989

Increases in thyroid gland blood flow after hemithyroidectomy in the rat.

After subtotal thyroidectomy, the thyroid gland remnant undergoes compensatory alterations in function and morphology. Under the trophic stimulation of elevated plasma TSH concentrations, the thyroid remnant responds with an increase in hormone synthesis and secretion and, in addition, increases in mass. We have examined the alterations in thyroid blood flow which accompany increased secretion and growth after hemithyroidectomy (HTX) in male Sprague-Dawley rats (200-220 g). At various times after surgical HTX (1, 2, and 3 weeks), blood samples for the determination of plasma hormone concentrations were obtained and tissue blood flows were determined using 15 +/- 5 microns diameter 141Ce-labeled microspheres in a modification of the reference sample microsphere technique. The microspheres were injected directly into the left cardiac ventricle via a 23-gauge needle passed through the chest wall while a reference blood sample was collected. After the animals were killed, tissues were cleaned and weighed, then tissue and reference blood sample radioactivities were determined. In addition, thyroidal immunoreactive vasoactive intestinal peptide was measured after acetic acid (0.67 N) extraction. After HTX, plasma TSH concentrations were significantly elevated. The plasma concentrations of T4 and T3 fell, but by less than the expected 50%. The mass of the remaining thyroid lobe increased progressively over the 3 weeks post thyroidectomy, reaching approximately 70% of the total thyroid gland weight of sham-operated controls. Thyroid blood flow per gram of tissue was significantly elevated at all times post HTX. HTX did not induce any alterations in thyroidal immunoreactive vasoactive intestinal peptide concentration. Thus, after HTX, the well documented compensatory alterations in thyroid remnant growth and secretion were accompanied by a prompt and striking increase in thyroid blood flow.

Animals↗
PubMed1989

Alterations in thyroid blood flow induced by varying levels of iodine intake in the rat.

Thyroid hormone biosynthesis depends upon the presence of adequate amounts of thyroidal iodine, and during fluctuations in dietary iodine intake, relatively constant thyroid hormone levels are maintained by various homeostatic mechanisms. These mechanisms include an enhancement of iodide pump efficiency and organification when iodine intake is limited, and significant decreases in iodide uptake and hormone synthesis when excess iodine intake occurs. The present study was designed to determine whether acclimation to different dietary iodine regimens is associated with changes in thyroid blood flow and to assess the time course of any such alterations in relation to pituitary-thyroid axis hormone levels. Male Sprague-Dawley rats were fed a diet containing low (LID), high (HID), or normal (CTR) iodine concentrations. Three, 7, 14, or 133 days after starting these dietary regimens, the animals were anesthetized with ketamine/pentobarbital, and thyroid blood flows were assessed using the reference sample version of the microsphere technique. At the same times and at weekly intervals throughout the 133 days of treatment, blood samples for the determination of TSH, T4, and T3 levels were obtained. Additionally, thyroidal immunoreactive vasoactive intestinal peptide (VIP) was measured at the end of the experiments. LID treatment increased thyroid blood flows to 240%, 350%, and 240% of levels in control rats at 7, 14, and 133 days of treatment, respectively. Thyroid weight was also elevated above levels in control animals at each of these times. A slight decrease in plasma T4 levels occurred over the 133 days of LID treatment; however, this dietary regimen did not alter circulating levels of T3 or TSH or thyroidal VIP concentration. HID treatment had opposite effects, in general, to those of LID. Thyroid blood flows were decreased by 34%, 56%, 46%, and 35% after 3, 7, 14, and 133 days of treatment with HID, respectively. Circulating levels of T4 were increased over the 133 days of HID treatment, whereas plasma levels of T3 and TSH and thyroid weights remained unchanged from those in control rats over this period of study. A small decrease in thyroidal VIP concentrations coincident with the decrease in thyroid blood flow was observed at the beginning of the HID treatment. Neither LID nor HID had any effect on blood pressure, cardiac output, or blood flow in other organs. These data demonstrate that acclimation to changes in dietary iodine intake in the rat include alterations in thyroid blood flow which are reciprocal to the iodine intake level and appear to be independent of circulating TSH levels.

Animals↗
PubMed1988

Survival, response and immune effects in a prospectively randomized study of dose strategy for alpha-N1 interferon.

Several tumour sites have now demonstrated objective responses to alpha interferons in a diversity of doses and schedules. Since effectiveness should be enhanced with the identification of an optimal dose strategy, we undertook a prospectively randomized study to compare an intermittent high dose escalating strategy (HDS) vs. a fixed low dose treatment in relation to clinical outcome and laboratory correlates of immune function. HDS patients received interferon alpha-N1 (lymphoblastoid interferon) 5M units m-2 by continuous i.v. infusion over 24 h, escalating by 5 M units m-2 day-1 as tolerated over 10 days, and repeated every 28 days. The low dose strategy (LDS) consisted of a fixed dose of 2 M units m-2 by intramuscular injection daily for 28 days, then daily for 7 days every other week. There were 53 evaluable patients. In keeping with earlier preliminary results there was evidence of improved immune function for HDS patients. They demonstrated a significant increase in the number of CD2+ (sheep red blood cell binding) cells and CD4+ (helper-inducer/suppressor-inducer) cells along with enhanced activity of natural killer cell, and mixed leukocyte culture activity. In addition to improved immune function, HDS patients survived longer than LDS (P = 0.04). Analysis of survival in relation to response suggested that monitoring of minor responses may be of interest for biological agents such as interferon.

Adult↗
PubMed1988

VIP and its homologues increase vascular conductance in certain endocrine and exocrine glands.

The effects of vasoactive intestinal peptide (VIP) and related structural homologues on tissue vascular conductances were investigated in anesthetized male rats. VIP, peptide histidine isoleucine (PHI), secretin, growth hormone-releasing factor (GHRF), gastric inhibitory peptide (GIP), or saline was infused intravenously over 4 min. Tissue blood flows were measured during this time by use of 141Ce-labeled microspheres. Regional blood flows were normalized for any change in mean arterial blood pressure during infusions, and results were expressed in terms of tissue vascular conductance (C). Circulating thyrotropin (TSH), triiodothyronine (T3), and thyroxine (T4) levels were determined before and at 20 min and 2 h after treatment. Marked increases in thyroid, pancreatic, and salivary gland vascular Cs occurred during peptide infusions with the order of potency (VIP greater than PHI greater than secretin greater than GHRF greater than GIP) correlating with the degree of structural homology to VIP. PHI and secretin produced maximal increases in vascular Cs, which were the same as those obtained with VIP. Circulating TSH, T3, and T4 levels were not different from values in saline-infused rats after peptide treatments that caused striking increases in thyroid vascular C. In the adrenal, kidney, and testis, VIP and its homologues had little to no effect on vascular Cs. We subsequently measured regional vascular Cs during VIP infusions in the presence or absence of secretin.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗