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Biomedical subjects

A Epple

Publications and source records attributed to A Epple.

At least 55 records · Page 3Linked to original sources
PubMed1984

Plasma steroids in the ammocoete of Petromyzon marinus.

Radioimmunoassays revealed the presence of the following steroids (or immunoreactive steroid fractions) in the plasma of larval sea lampreys: progesterone, corticosterone, cortisol, androstenedione, testosterone, dihydrotestosterone, estrone, and estradiol. Several types of stress served to provoke the release of these substances. A statistically significant effect of the treatment was noted under only one condition: squeezing of the body of decapitated ammocoetes during blood collection caused an increase in plasma dihydrotestosterone and a decrease in plasma estradiol. The discovery of all eight steroids (or immunoreactivities) assayed for suggests that the plasma of the ammocoete may contain a considerable number of additional steroids yet to be identified.

Androstenedione↗
PubMed1984

Effects of fasting, pancreatectomy, and hypophysectomy in the yellow eel, Anguilla rostrata.

Metabolic effects of pancreatectomy and hypophysectomy are investigated in the yellow American eel, Anguilla rostrata, fasted for 6 months. The results are compared with the findings in freshly captured eels subjected to the same operations. In intact animals, fasting causes a statistically significant decrease in serum amino acid nitrogen (AAN), serum urea, and relative liver weight, and an increase in serum free fatty acids (FFA), serum cholesterol, and tissue hydration. Serum glucose, liver and muscle glycogen, liver and muscle fatty acids, and abdominal fat stores do not show significant alterations. The absence of diabetes mellitus after pancreatectomy, seen in previous studies, is confirmed. However, pancreatectomy affects fewer parameters in fasting eels than in fed ones. After hypophysectomy, the situation is similar; only serum AAN shows an impact of the operation in fasted eels. As in freshly captured eels, surgical stress seems to affect almost all metabolic parameters. It appears that the smaller impact of both pancreatectomy and hypophysectomy in fasted eels reflects the reduced role of hormones in the state of lowered metabolism.

Amino Acids↗
PubMed1984

The effect of catecholamines on branchial and cardiac electrical recordings in adult lampreys (Geotria australis).

A method is described for injecting CAs into the caudal vein of unanaesthetized lampreys and monitoring any subsequent changes in branchial and cardiac electrical recordings. While a dose of 5-6 micrograms kg-1 body wt of norepinephrine increased the rate and amplitude of branchial and cardiac electrical recordings, the same dose of epinephrine produced a comparable effect only on the heart recordings. A dose of 5-6 micrograms kg-1 body wt of dopamine had a relatively small effect on branchial and cardiac electrical recordings. The response to CAs by lampreys is apparently dose related. The above results have been used to suggest possible ways by which CAs influence cardiac and respiratory functions in lampreys.

Animals↗
PubMed1983

Effects of exogenous somatostatin and antisomatostatin on serum parameters of the American eel.

1. Bolus injections of a wide range of concns. of somatostatin and of antisomatostatin, in cardiac-cannulated eels had no specific effects on serum osmolality, sodium, potassium and chloride. 2. A presumably physiological dose of somatostatin had a pronounced and sustained hyperglycemic effect beginning 160 min after the injection, which was absent at higher doses. However, an extremely high dose caused an early, temporary hyperglycemia. 3. Antisomatostatin also caused a hyperglycemia, which appeared after 20 min and lasted less than 24 hr. 4. It appears that, in the freshwater eel, somatostatin affects both hyper- and hypoglycemic mechanisms and that these effects depend on its concn and/or site of action.

Anguilla↗
PubMed1982

Catecholamines in head and body blood of eels and rats.

1. When compared with other vertebrates, the circulating titers of norepinephrine and epinephrine of the yellow eel are very low. 2. The ratio of the catecholamine titers in the eel differs from that reported for other vertebrates. 3. Following decapitation, the titers of the catecholamines are higher in head blood than in body blood of both unanesthetized and anesthetized eels. In decapitated rats, only the dopamine titer is higher in head blood. 4. As in the lamprey, agitation stress causes a drop of circulating catecholamines. However, other forms of stress cause the expected increase. 5. It appears that many data on catecholamines in both brain and circulation of vertebrates in general have been influenced by stress effects.

Animals↗
PubMed1977

Pancreatectomy in a teleost fish, Anguilla rostrata (American eel).

A technique for pancreatectomy was described for the American eel. In this fish, the operation was not followed by the typical signs of diabetes mellitus. Histodensitometric determination of liver glycogen showed no major differences between operated controls and pancreatectomized eels. The absence of a specific hyperglycemia, previously reported with the hexokinase method, was confirmed with the glucose oxidase technique; however, the more specific hexokinase method gave consistently lower values. Breakdown of adipose tissue and hyperlipemia were absent.

Animals↗
PubMed1976

New types of islet cells in a cyclostome, Petromyzon marinus L.

Four types of acidophilic granular cells, in addition to B-cells, are identified in the islet organ of anadromous specimens of two subspecies of Petromyzon marinus by light and electron microscopy. Three of these acidophils (PI, PII and PIV-cells) occur in both the cranial and hepatic islets while a fourth type (PIII-cell) has only been found in the hepatic islet of some animals. The granules of the PI-cells stain with ponceau de xylidine, give a distinct tryptophan reaction and in ultrastructural examination show large, dense granules. The PII-cells contain unusual crystals and appear to be a non-secretory stage of the PI. The PIII-cells stain deep-red and acid fuchsin. They contain very large, dense granules and some lysosomes. PIV-cells stain selectively with phosphotungstic acid-hematoxylin and ultrastructurally, contain small, more or less dense granules. It appears that PI- and PIV-cells develop directly from B-cells, while the PIII-cells derive from PI-cells. despite their direct or indirect origin from B-cells, the PI-, PIII- and PIV-cells show characteristic features of functionally independent endocrine cells. Petromyzon marinus may be an ideal model for the understanding of phylogenetic and pathological interrelationships between islet and gastrointestinal hormones. It is clear that the interpretation of the islet organ of the cyclostomes, which has been generally considered a source of insulin only, requires a revaluation.

Animals↗
PubMed1972

[Pancreatectomy in the eel: effects on serum glucose and cholesterol].

Pancreatectomy in the eel causes a slight tendency toward hyperglycemia; total and partial pancreatectomies cause a drop of total serum cholesterol. Thus, complete removal of the islet tissue in this teleost is not followed by diabetes mellitus, and also the endocrine control of the cholesterol-containing serum components seems to differ from that in mammals.

Animals↗