Fetal and neonatal rat pancreas in organ culture age-related effects of corticosterone on the acinar cell component

The neonatal rat is very sensitive to the lethal effects of bacterial endotoxin. Because of the adaptive importance of pituitary-adrenal secretions to stress, this study examined the ontogeny of the plasma corticosterone and adrenocorticotropic hormone (ACTH) responses to endotoxin. The lethal sensitivity of young rats to endotoxin ranged from 0.5 to 30 mg/kg (ip) in the 1- to 21-day-old rat. After endotoxin treatment, the 1- and 2-day-old rat showed marked elevations of corticosterone similar in magnitude to that seen in 21-day-old and adult rats; however, significantly depressed corticosterone increments were observed in the 5-, 10-, and 14-day-old rats. This age-related pattern of adrenocortical secretion was correlated with the developing rat's corticosterone response to exogenous ACTH. In contrast, endotoxin administered to 5-, 10-, and 14-day-old rats resulted in increments of plasma ACTH similar to those observed in the 21-day-old and adult rats. Although plasma ACTH levels increased by 84-127% in the 1- and 2-day-old rats, these increases were significantly less than those of rats at all other ages tested. Thus the newborn rat mounts an effective corticosterone response to endotoxin, loses this ability between ages 5-14 days, and regains this response at 21 days of age. Because the hyporesponsive ages exhibit a marked increase in ACTH secretion, the loss of the adrenocortical response to endotoxin appears to be a result of a depressed responsiveness of the adrenal cortex to ACTH.

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Altered drug metabolizing potential of acinar cell lesions induced in rat pancreas by hydroxyaminoquinoline 1-oxide

Carcinogenesis ◽

10.1093/carcin/8.8.1089 ◽

1987 ◽

Vol 8 (8) ◽

pp. 1089-1094 ◽

Cited By ~ 9

Author(s):

Malcolm A. Moore ◽

Takao Makino ◽

Shigeki Tsuchida ◽

Kiyomi Sato ◽

Akira Ichihara ◽

...

Keyword(s):

Acinar Cell ◽

Rat Pancreas

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Evidence for high peptide α-amidation activity in the neonatal rat pancreas

Biochemical and Biophysical Research Communications ◽

10.1016/0006-291x(86)90263-9 ◽

1986 ◽

Vol 138 (1) ◽

pp. 179-184 ◽

Cited By ~ 11

Author(s):

L'H. Ouafik ◽

A. Dutour ◽

P. Salers ◽

P. Giraud ◽

F. Boudouresque ◽

...

Keyword(s):

Neonatal Rat ◽

Rat Pancreas

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Changes in sensitivity to Norepinephrine and Methacholine of neonatal rat vas deferens after organ culture

The Japanese Journal of Pharmacology ◽

10.1016/s0021-5198(19)54267-6 ◽

1982 ◽

Vol 32 ◽

pp. 285

Author(s):

Koki Shigenobu ◽

Kageyoshi Ono ◽

Yutaka Kasuya

Keyword(s):

Organ Culture ◽

Vas Deferens ◽

Rat Vas Deferens ◽

Neonatal Rat

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Postnatal development of the renin-angiotensin system in rats

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1980.238.5.r432 ◽

1980 ◽

Vol 238 (5) ◽

pp. R432-R437 ◽

Cited By ~ 8

Author(s):

K. B. Wallace ◽

J. B. Hook ◽

M. D. Bailie

Keyword(s):

Steady State ◽

Renin Angiotensin System ◽

Plasma Renin ◽

Rat Plasma ◽

Neonatal Rat ◽

Postnatal Life ◽

Renin Substrate ◽

Angiotensin System ◽

Renin Angiotensin ◽

Age Related

The purpose of this investigation was to correlate the development of the various enzyme activities associated with the renin-angiotensin system with age-related differences in the steady-state concentrations of angiotensin I (AI) and II (AII). Angiotensin was quantified by radioimmunoassay. Plasma renin activity and concentration increased between birth and 3 wk of age, and declined thereafter to adult values. Renal renin content, on the other hand, increased throughout the first 6 wk of postnatal life. The concentration of AII in plasma also increased following birth; however, maximum concentrations were not attained until 5 wk of age. In contrast, plasma AI did not increase between 3 and 6 wk of age. These data suggest that the steady-state concentration of AII in neonatal rat plasma may be partially limited by the low plasma renin substrate concentration. The increase in AII between 3 and 6 wk of age may reflect the increasing converting enzyme activity.

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Developmental maturation of Na(+)-H+ exchange in rat renal tubular brush-border membrane

AJP Renal Physiology ◽

10.1152/ajprenal.1991.261.6.f1017 ◽

1991 ◽

Vol 261 (6) ◽

pp. F1017-F1025 ◽

Cited By ~ 4

Author(s):

I. Zelikovic ◽

E. Stejskal ◽

P. Lohstroh ◽

A. Budreau ◽

R. W. Chesney

Keyword(s):

Brush Border ◽

Brush Border Membrane ◽

Initial Rate ◽

Neonatal Rat ◽

Adult Rats ◽

Luminal Membrane ◽

Age Related ◽

Proximal Tubular ◽

Na Uptake ◽

Developmental Maturation

The developmental maturation of the Na(+)-H+ exchanger present in the proximal tubular luminal membrane of the rat was investigated. An overshoot of 1 mM Na+ uptake was evident in brush-border membrane vesicles derived from the renal cortex of 7- and 21-day-old and adult rats in the presence of an outwardly directed H+ concentration ([H+]) gradient [intravesicular pH (pHi) = 5.5; extravesicular pH (pHo) = 7.5]. Na+ uptake was amiloride sensitive at all ages examined. Significantly higher initial rate (3 s) Na+ uptake and peak accumulation (60 s) in the presence of a [H+] gradient were found in vesicles from 7-day-old rats compared with adult animals. Significantly enhanced initial rate Na+ uptake by neonatal vesicles was also evident under pH-equilibrated conditions (pHi = pHo = 7.5). An age-related decrease in amiloride-sensitive Na+ accumulation by vesicles was found. Kinetic analysis of Na(+)-H+ exchange in voltage-clamped vesicles, in the presence of dimethylamiloride (DMA), and calculating 5-s Na+ uptake values showed a maturational decrease in capacity (decreasing Vmax) coupled with a maturational increase in affinity (decreasing Km) of Na(+)-H+ antiport. These data suggest that an enhanced amiloride-inhibitable Na(+)-H+ exchange activity due to increased capacity of exchange exists in the proximal tubular luminal membrane of the neonatal rat. This increased Na(+)-H+ exchange may potentially contribute to positive Na+ balance in the growing organism and may rapidly dissipate the electrochemical Na+ gradient across the luminal membrane necessary for Na(+)-solute contransport, thereby contributing to glycosuria and aminoaciduria of early life.

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Organ culture of rat heart: maintained high sensitivity of fetal atria before innervation to norepinephrine

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y88-147 ◽

1988 ◽

Vol 66 (7) ◽

pp. 901-906 ◽

Cited By ~ 8

Author(s):

Hikaru Tanaka ◽

Yutaka Kasuya ◽

Hiroshi Saito ◽

Koki Shigenobu

Keyword(s):

Organ Culture ◽

Culture Medium ◽

Sympathetic Innervation ◽

High Sensitivity ◽

Fold Increase ◽

Neonatal Rat ◽

Fetal Period ◽

Sensitivity Changes ◽

Β Receptor ◽

Right Atria

Changes in sensitivity to norepinephrine (NE) of fetal and neonatal rat right atria placed in organ culture were examined. The high sensitivity to NE of the 17-day fetal atria was maintained during organ culture for 5 days. The pD2 value for NE at the 17th day of gestation was 8.66 ± 0.09, and that after organ culture for 5 days was 8.62 ± 0.09. The sensitivity of 1-day-old neonatal artia was significantly lower than that of fetal atria; but when they were cultured for 24 h, there was a 10-fold increase in sensitivity. The pD2 value before culture was 7.59 ± 0.05, and that after culture was 8.54 ± 0.04. NE added to the culture medium prevented this increase in sensitivity. Similar changes were observed in the sensitivity to isoproterenol, but not in the sensitivity to forskolin, indicating that these sensitivity changes were of a postjunctional nature and most likely due to some changes in the β-receptor and (or) its coupling to adenylate cyclase. Therefore, the decrease in myocardial sensitivity to NE observed during the late fetal period is most likely to be caused by factor(s) related to sympathetic innervation.

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Distribution of amylase and chymotrypsin in four regions of the rat pancreas

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y81-132 ◽

1981 ◽

Vol 59 (8) ◽

pp. 884-886 ◽

Cited By ~ 1

Author(s):

Adrien R. Beaudoin ◽

Pierre St-Jean ◽

Ginette Girard

Keyword(s):

Protein Content ◽

Acinar Cell ◽

Dna Content ◽

Pancreatic Tissue ◽

Weight Basis ◽

Secretory Proteins ◽

Fresh Weight ◽

Fresh Weight Basis ◽

Rat Pancreas

Recent observations have confirmed the existence of more than one pool of secretory proteins in the rat pancreatic tissue. To determine if these different pools could be located in the different regions of the rat pancreas, the amylase and chymotrypsin contents have been measured in the biliary, duodenal, gastric, and splenic regions. On a tissue DNA content, protein content, or a fresh weight basis, the proportions of these two enzymes are comparable in the four regions. It is therefore postulated that heterogeneity of enzyme composition exists either within these regions or within the acinar cell itself.

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