Effects of Temperature on Responses of the Gonads of Green Sunfish (Lepomis cyanellus) to Treatment with Carp Pituitaries and Testosterone Propionate

1973 ◽  
Vol 30 (7) ◽  
pp. 905-912 ◽  
Author(s):  
Calvin M. Kaya
Keyword(s):  
Low Temperatures ◽  
Elevated Temperatures ◽  
Testosterone Propionate ◽  
Lepomis Cyanellus ◽  
Pituitary Glands ◽  
Effects Of Temperature ◽  
Gonadal Recrudescence ◽  
Green Sunfish ◽  
The Brain ◽  
Stimulation Of

Previous investigations have demonstrated that stimulation of gonadal recrudescence in the green sunfish (Lepomis cyanellus) depends on the concurrent presence of long photoperiods (15 hr) and elevated temperatures (> 15 C). The present investigation indicates that recrudescence can be stimulated in seasonally regressed ovaries and testes by injections of a crude extract of fish pituitary glands, and in testes by testosterone propionate, but only under elevated temperature. The low temperatures that block gonadal responses to long photoperiods also effectively prevent gonadal responses to administered hormones. These observations indicate that the responsiveness of the gonads of this species to stimulating hormones is markedly modified by temperature; however, the results do not obviate the possibility that secretion of gonadotropins by the brain–pituitary system may also be affected.

Vertical banding evoked by electrical stimulation of the brain in anaesthetized green sunfish, Lepomis cyanellus, and bluegills, Lepomis macrochirus

1980 ◽  
Vol 84 (1) ◽  
pp. 149-160
Author(s):  
D. H. Bauer ◽  
L. S. Demski
Keyword(s):  
Electrical Stimulation ◽  
Transition Zone ◽  
Lepomis Macrochirus ◽  
Optic Tract ◽  
Colour Change ◽  
The Body ◽  
Lepomis Cyanellus ◽  
Green Sunfish ◽  
The Brain ◽  
Stimulation Of

A pattern of dark vertical bands is a characteristic agonistic display in the green sunfish, Lepomis cyanellus and the bluegill, L. macrochirus. The rapidity with which the display can appear and disappear indicates that it is neurally controlled. Electrical stimulation of the brain was carried out in anaesthetized green sunfish and bluegills to map those regions from which this colour change can be elicited. Banding was evoked by stimulation of sites near the midline in the preoptic area, ventral thalamic-dorsal hypothalmic transition zone, the midbrain tegmentum (just dorsal to the nucleus prerotundus pars medialis), in and near the torus semicricularis, in the basal midbrain (region of the crossing tectobulbar tracts), and in the rostral basomedial medulla. A ‘transition’ zone was located basally in the middle medulla, caudal to which only paling was evoked. Areas found to be negative for evoked banding included the telencephalic lobe, the inferior lobe of the hypothalamus, the optic tract, the optic tectum, the body and valvula of the cerebellum and the caudal medulla. It is postulated that the vertical banding pattern is made up of a separate, selectively controlled system of dermal melanophores. The possible neural mechanisms controlling banding are discussed.

Concentrations of Dieldrin in the Blood and Brain of the Green Sunfish, Lepomis cyanellus, at Death

1971 ◽  
Vol 28 (4) ◽  
pp. 610-612 ◽  
Author(s):  
Roger L. Hogan ◽  
Eugene W. Roelofs
Keyword(s):  
Correlation Coefficient ◽  
Lepomis Cyanellus ◽  
Green Sunfish ◽  
The Brain ◽  
Brain Water

When green sunfish, Lepomis cyanellus, were exposed to concentrations of dieldrin averaging 6 ppb for periods ranging from 124 to 139 hr, the concentrations of dieldrin in the blood and brain at death were approximately 6.0 and 9.0 μg/g. Surviving fish had concentrations markedly lower than those that died. A correlation coefficient of 0.95 was found between concentrations of dieldrin in the blood and in the brain, water dieldrin concentrations having a slight influence on the concentrations in the blood at death. Surviving fish exhibiting severe poisoning symptoms had higher concentrations of dieldrin in the blood and brain than did those showing moderate to minimal symptoms.

The trypanosomes of Ranidae. I. The effects of temperature and diurnal periodicity on the peripheral parasitaemia in the bullfrog (Rana catesbeiana Shaw)

1969 ◽  
Vol 47 (3) ◽  
pp. 283-288 ◽  
Author(s):  
J. E. Bardsley ◽  
R. Harmsen
Keyword(s):  
Metabolic Activity ◽  
Low Temperatures ◽  
Elevated Temperatures ◽  
Rana Catesbeiana ◽  
Insect Vector ◽  
Short Term ◽  
Type D ◽  
Effects Of Temperature ◽  
Morph Type

The peripheral parasitaemia of the Trypanosoma rotatorium complex in the bullfrog (Rana catesbeiana) is markedly affected by temperature. Over the long term, high temperatures are always coincident with high peripheral parasitaemia and vice versa; over the short term, increases in temperature bring about a corresponding increase in parasite level, and vice versa. A distinct diurnal cyclicity in parasitaemic level is found for one morph (type D) at elevated temperatures (26 °C); no such cyclicity was apparent at low temperatures (10 °C). Other morphs did not display any cyclicity at either temperature. It is proposed that the control of peripheral parasitaemia is due to changes in the level of metabolic activity of the host.Natural selection will favor any behavioral or growth pattern among trypanosomes which results in an increased peripheral parasitaemia at times and under conditions of optimal host–vector contact. The present results suggest an optimal host–vector contact for basking frogs. The possibility of an insect vector is discussed.

PERIPHERAL AND CENTRAL ANDROGENIC STIMULATION OF SEXUAL BEHAVIOUR OF CASTRATED MALE RATS

1977 ◽  
Vol 84 (4) ◽  
pp. 813-828 ◽  
Author(s):  
Rachel Hamburger-Bar ◽  
Henk Rigter
Keyword(s):  
Sexual Behaviour ◽  
Testosterone Propionate ◽  
Male Rats ◽  
Peripheral Target ◽  
Peripheral Tissues ◽  
Target Organs ◽  
The Brain ◽  
Stimulation Of ◽  
Maintenance Study

ABSTRACT The effects of androgens on the maintenance and restoration of sexual behaviour (mounts, intromissions and ejaculations) of castrated male rats were studied. In the maintenance study the rats were treated during 5 weeks, starting one day following castration. Testosterone propionate maintained sexual behaviour at an almost normal level. The androgenoestrogen intermediate 19-hydroxytestosterone propionate was unable to prevent the decline in the number of ejaculations over the weeks although this hormone maintained the post-ejaculatory refractory period in those rats that ejaculated and also maintained normal sexual latencies. In the restoration study administration of testosterone propionate during 7 weeks to long-term castrated rats restored sexual behaviour to normal. 19-Hydroxytestosterone propionate treated rats displayed mounts but no other signs of sexual behaviour. The 5α-reduced androgen dihydrotestosterone propionate did not restore sexual behaviour. Testosterone propionate and dihydrotestosterone propionate stimulated peripheral target organs; 19-hydroxytestosterone propionate was ineffective in this respect. It has been suggested that testosterone might stimulate sexual behaviour in rats in two ways, i. e., via its aromatization to oestradiol in the brain, and by stimulating growth of peripheral tissues via its 5α-reduction to dihydrotestosterone. In support for this view we have found that the combination of 19-hydroxytestosterone propionate and dihydrotestosterone propionate was effective in restoring the full pattern of sexual behaviour in castrated male rats.

LUTEINIZING HORMONE RELEASING FACTOR IN ULTRAFILTRATES OF BLOOD COLLECTED FROM THE PITUITARY STALK OF OVARIECTOMIZED RATS AND RATS SUBJECTED TO ELECTRICAL STIMULATION OF THE PREOPTIC AREA

1972 ◽  
Vol 54 (2) ◽  
pp. 227-237 ◽  
Author(s):  
H. G. BURGER ◽  
G. FINK ◽  
V. W. K. LEE
Keyword(s):  
Electrical Stimulation ◽  
Luteinizing Hormone ◽  
Preoptic Area ◽  
Male Rats ◽  
Pituitary Stalk ◽  
Ovariectomized Rats ◽  
Serum Lh ◽  
Pituitary Glands ◽  
The Brain ◽  
Stimulation Of

SUMMARY The presence of luteinizing hormone releasing factor (LH-RF) activity was investigated in pituitary stalk and systemic blood collected from rats ovariectomized at least 3 weeks previously, and in stalk blood from male rats in which electrodes had been implanted in the medial preoptic area of the brain. Most of the assayable luteinizing hormone (LH) present in the blood samples was eliminated by acid-ethanol extraction followed by ultrafiltration. The ultrafiltrates were injected into ovariectomized rats treated with oestrogen and progesterone, and increments in the concentration of LH in the sera of these animals, estimated by radioimmunoassay, were taken as an indication that the filtrate was able to release LH from the anterior pituitary gland. The ultrafiltrates of both the stalk and systemic plasma from the ovariectomized rats exhibited LH-RF activity as did the ultrafiltrates of blood collected from the pituitary stalk of the male rats during electrical stimulation of the preoptic area; stalk blood collected from these animals before the current was applied appeared to be inactive. The LH-RF activity of the ultrafiltrates of systemic and pituitary stalk plasma taken from ovariectomized rats was similar, and, therefore, the possibility is raised that the response of the pituitary glands in ovariectomized rats treated with oestrogen and progesterone is of an all or none type. The presence of appreciable quantities of LH-RF in the systemic plasma of ovariectomized rats may explain the discrepancy between bioassay and immunoassay estimates of LH in the plasma of these animals. The rapid increase in the concentration of serum LH and in the LH-RF activity of pituitary stalk plasma which followed stimulation of the preoptic area suggests that this region of the brain may be important in the control of the secretion of LH in the male as well as in the female animal.

Morphometric Analysis of the Hepatocytes from Fish Exposed to Arsenic

1976 ◽  
Vol 34 ◽  
pp. 282-283
Author(s):  
Elsie M. B. Sorensen
Keyword(s):  
Morphometric Analysis ◽  
Arsenic Concentration ◽  
Ultrastructural Changes ◽  
Sodium Arsenate ◽  
Lepomis Cyanellus ◽  
Mammalian Counterpart ◽  
Intracellular Changes ◽  
Green Sunfish ◽  
Organic Pesticides

The detoxification capacity of the liver is well documented for a variety of substances including ethanol, organic pesticides, drugs, and metals. The piscean liver, although less enzymatically active than the mammalian counterpart (1), contains endoplasmic reticulum with an impressive repertoire of oxidizing, reducing, and conjugating abilities (2). Histopathologic changes are kncwn to occur in fish hepatocytes following in vivo exposure to arsenic (3); however, ultrastructural changes have not been reported. This study involved the morphometric analysis of intracellular changes in fish parynchymal hepatocytes and correlation with arsenic concentration in the liver.Green sunfish (Lepomis cyanellus, R.) were exposed to 0, 30, or 60 ppm arsenic (as sodium arsenate) at 20°C for 1, 2, or 3 week intervals before removal of livers for quantification of the arsenic burden (using neutron activation analysis) and morphometric analysis of ultrastructural alterations. Livers were cut into 1 mm cubes for fixation, dehydration, and embedding.

Stereological Analyses of Hepatocyte Ultrastructure Monitor Arsenic Liver Burdens

1980 ◽  
Vol 38 ◽  
pp. 442-443
Author(s):  
E. M. B. Sorensen ◽  
R. R. Mitchell ◽  
L. L. Graham
Keyword(s):  
Drainage System ◽  
Water Levels ◽  
Ultrastructural Changes ◽  
Hepatocyte Ultrastructure ◽  
Lepomis Cyanellus ◽  
Large Numbers ◽  
Activation Data ◽  
Water Analyses ◽  
Municipal Lake ◽  
Green Sunfish

Endemic freshwater teleosts were collected from a portion of the Navosota River drainage system which had been inadvertently contaminated with arsenic wastes from a firm manufacturing arsenical pesticides and herbicides. At the time of collection these fish were exposed to a concentration of 13.6 ppm arsenic in the water; levels ranged from 1.0 to 20.0 ppm during the four-month period prior. Scale annuli counts and prior water analyses indicated that these fish had been exposed for a lifetime. Neutron activation data showed that Lepomis cyanellus (green sunfish) had accumulated from 6.1 to 64.2 ppm arsenic in the liver, which is the major detoxification organ in arsenic poisoning. Examination of livers for ultrastructural changes revealed the presence of electron dense bodies and large numbers of autophagic vacuoles (AV) and necrotic bodies (NB) (1), as previously observed in this same species following laboratory exposures to sodium arsenate (2). In addition, abnormal lysosomes (AL), necrotic areas (NA), proliferated rough endoplasmic reticulum (RER), and fibrous bodies (FB) were observed. In order to assess whether the extent of these cellular changes was related to the concentration of arsenic in the liver, stereological measurements of the volume and surface densities of changes were compared with levels of arsenic in the livers of fish from both Municipal Lake and an area known to contain no detectable level of arsenic.

Chemical Stimulation of the Brain Makes Stimulating Reading

1975 ◽  
Vol 20 (12) ◽  
pp. 923-924
Author(s):  
MADGE E. SCHEIBEL ◽  
ARNOLD B. SCHEIBEL
Keyword(s):  
Chemical Stimulation ◽  
The Brain ◽  
Stimulation Of
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