THE EFFECT OF CASTRATION ON CYCLICALLY VARYING SEXUAL FUNCTIONS IN THE MALE RABBIT

1964 ◽  
Vol 46 (4) ◽  
pp. 608-612 ◽  
Author(s):  
Otto Hornstein ◽  
Jan Erik Kihlström ◽  
Gunnar Degerman
Keyword(s):  
Body Temperature ◽  
Adult Male ◽  
Relative Frequency ◽  
Cyclic Variation ◽  
Male Rabbit ◽  
Hormonal Effect ◽  
Exfoliated Cells ◽  
Different Types ◽  
Cyclic Variations

ABSTRACT One of the phenomena found to vary cyclically in adult male rabbits is the relative frequency of exfoliated cells from the urethral epithelium. Assuming that there is a hormonal effect on this periodicity, the authors have studied the relative frequency of different types of cells in urethral smears collected daily after orchidectomy. No cyclic variations in the frequency of these cells could be detected in the castrated buck. Moreover, the proportion between the different types of cells was profoundly changed. The results show that the frequency of these cells and their cyclic occurrence are regulated by the testicular hormones. However, the cyclic variation in body temperature described in a previous paper persisted after castration and has thus to be considered as independent of the testicular hormones.

OBSERVATIONS INDICATING A SEX CYCLE IN THE MALE RABBIT

1964 ◽  
Vol 46 (4) ◽  
pp. 597-607 ◽  
Author(s):  
Jan Erik Kihlström ◽  
Otto Hornstein
Keyword(s):  
Body Temperature ◽  
Mucous Membrane ◽  
Immature Stage ◽  
Male Urethra ◽  
Male Rabbit ◽  
Exfoliated Cells ◽  
Different Types ◽  
The Mean ◽  
Male Sex ◽  
Sex Cycle

ABSTRACT Recently some physiological characteristics of a sex cycle in male animals have been demonstrated. However, nothing is known at present about any morphological expressions of this cycle, and particularly about any rhythmical variation in exfoliation of cells comparable with that of the vaginal mucous membrane. On the assumption that such a rhythm may occur in the male urethra, the exfoliation of cells in this organ has been studied by taking daily smears. Cyclically varying frequencies of four different types of exfoliated cells, mainly in an immature stage, were demonstrated. Only a fifth type of cells, characterized by cornification and nuclear degeneration, is not subjected to such rhythmical variation. The mean duration of these cycles is about four days. Simultaneous investigations on the seminal volume and body temperature showed some relation to the cycle of cell desquamation. The results give additional evidence for the existence of a male sex cycle, probably with a hormonal background.

“On-” and “off-” cells in the rostral ventromedial medulla of rats held in thermoneutral conditions: are they involved in thermoregulation?

2014 ◽  
Vol 112 (9) ◽  
pp. 2199-2217 ◽  
Author(s):  
Nabil El Bitar ◽  
Bernard Pollin ◽  
Daniel Le Bars
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Body Temperature ◽  
Core Body Temperature ◽  
Rostral Ventromedial Medulla ◽  
Sequence Of Events ◽  
Ventromedial Medulla ◽  
Cyclic Variations ◽  
On And Off Cells ◽  
Core Body

In thermal neutral condition, rats display cyclic variations of the vasomotion of the tail and paws, synchronized with fluctuations of blood pressure, heart rate, and core body temperature. “On-” and “off-” cells located in the rostral ventromedial medulla, a cerebral structure implicated in somatic sympathetic drive, 1) exhibit similar spontaneous cyclic activities in antiphase and 2) are activated and inhibited by thermal nociceptive stimuli, respectively. We aimed at evaluating the implication of such neurons in autonomic regulation by establishing correlations between their firing and blood pressure, heart rate, and skin and core body temperature variations. When, during a cycle, a relative high core body temperature was reached, the on-cells were activated and within half a minute, the off-cells and blood pressure were depressed, followed by heart rate depression within a further minute; vasodilatation of the tail followed invariably within ∼3 min, often completed with vasodilatation of hind paws. The outcome was an increased heat loss that lessened the core body temperature. When the decrease of core body temperature achieved a few tenths of degrees, sympathetic activation switches off and converse variations occurred, providing cycles of three to seven periods/h. On- and off-cell activities were correlated with inhibition and activation of the sympathetic system, respectively. The temporal sequence of events was as follows: core body temperature → on-cell → off-cell ∼ blood pressure → heart rate → skin temperature → core body temperature. The function of on- and off-cells in nociception should be reexamined, taking into account their correlation with autonomic regulations.

Characterizing the cyclic variability of ignition timing in a homogeneous charge compression ignition engine fuelled with n-heptane/iso-octane blend fuels

2008 ◽  
Vol 9 (5) ◽  
pp. 361-397 ◽  
Author(s):  
M Shahbakhti ◽  
C R Koch
Keyword(s):  
Equivalence Ratio ◽  
Homogeneous Charge Compression Ignition ◽  
Coolant Temperature ◽  
Cyclic Variation ◽  
Compression Ignition ◽  
Ignition Timing ◽  
Compression Ignition Engine ◽  
Hcci Combustion ◽  
Cyclic Variations ◽  
Homogeneous Charge

The cyclic variations of homogeneous charge compression ignition (HCCI) ignition timing is studied for a range of charge properties by varying the equivalence ratio, intake temperature, intake pressure, exhaust gas recirculation (EGR) rate, engine speed, and coolant temperature. Characterization of cyclic variations of ignition timing in HCCI at over 430 operating points on two single-cylinder engines for five different blends of primary reference fuel (PRF), (iso-octane and n-heptane) is performed. Three distinct patterns of cyclic variation for the start of combustion (SOC), combustion peak pressure ( Pmax), and indicated mean effective pressure (i.m.e.p.) are observed. These patterns are normal cyclic variations, periodic cyclic variations, and cyclic variations with weak/misfired ignitions. Results also show that the position of SOC plays an important role in cyclic variations of HCCI combustion with less variation observed when SOC occurs immediately after top dead centre (TDC). Higher levels of cyclic variations are observed in the main (second) stage of HCCI combustion compared with that of the first stage for the PRF fuels studied. The sensitivity of SOC to different charge properties varies. Cyclic variation of SOC increases with an increase in the EGR rate, but it decreases with an increase in equivalence ratio, intake temperature, and coolant temperature.

THE INFLUENCE OF OVERCROWDING ON SPERMATOGENESIS, SIZE OF LEYDIG-CELL NUCLEI (HISTOMETRICAL INVESTIGATION), AND THE ADRENAL CORTICOSTERONE CONTENTS IN MICE

1973 ◽  
Vol 74 (4) ◽  
pp. 783-791 ◽  
Author(s):  
K. Gärtner ◽  
H. Reznik-Schüller ◽  
G. Reznik
Keyword(s):  
Population Size ◽  
Group Size ◽  
Adult Male ◽  
Leydig Cell ◽  
Relative Frequency ◽  
Seminiferous Tubules ◽  
Cell Nuclei ◽  
Nmri Mice ◽  
Testosterone Secretion ◽  
Adrenal Corticosterone

ABSTRACT Adult male NMRI-mice were kept alone or in groups of 5, 10, 20, 30, 40 and 60 animals for 28 days and were then sacrificed. The corticosterone levels of their adrenals were determined and their testes were examined histometrically. The corticosterone levels of the adrenals increased two-fold with increasing population size. Furthermore the increased population size caused a suppression of some testicular functions: the seminiferous tubules decreased up to 20 % and the relative frequency of the spermatids up to 10 % whereas the numbers of spermatocytes and spermatogonias increased correspondingly. A decrease of about 25 % of the testosterone dependent postmeiotic stages of spermatogenesis is assumed. Since the diameters of the Leydig-cell nuclei decreased about 20 %, a reduction of the testicular testosterone secretion can be projected. All measurements proved the group with 5 animals to be the most favourable group size.

Heart rate and body temperature during free diving of Weddell seals

1987 ◽  
Vol 253 (2) ◽  
pp. R344-R351 ◽  
Author(s):  
R. D. Hill ◽  
R. C. Schneider ◽  
G. C. Liggins ◽  
A. H. Schuette ◽  
R. L. Elliott ◽  
...  
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Adult Male ◽  
Fetal Heart Rate ◽  
Fetal Heart ◽  
Weddell Seal ◽  
The Body ◽  
Weddell Seals ◽  
The Mean ◽  
Slow Onset

We have developed and successfully used the first microprocessor-controlled monitors for collection of data on depth, heart rate, and body temperature of one fetal and five adult male freely swimming Weddell seals. Adult seals almost invariably experienced a prompt bradycardia at the start of each dive, and the mean heart rate during diving was significantly lower for dives greater than 20 min (P greater than 0.999). The heart rate was also significantly greater during the ascent portion of dives when compared with the descent portion (P greater than 0.95). The fetal seal experienced a slow onset of bradycardia when its mother dived; during diving the fetal heart rate decreased by an average of 1.1 beats/min for each minute of the dive. The fetal heart rate generally took approximately 10 min to recover to predive levels after its mother resurfaced to breathe. The body temperature of one adult male Weddell seal showed a decrease of greater than 1.5 degrees C from resting levels before dives of greater than 15 min were initiated and a drop of over 2 degrees C before dives of greater than 30 min duration.

scholarly journals Different types of soluble fermentable dietary fibre decrease food intake, body weight gain and adiposity in young adult male rats

2014 ◽  
Vol 11 (1) ◽  
pp. 36 ◽  
Author(s):  
Clare L Adam ◽  
Patricia A Williams ◽  
Matthew J Dalby ◽  
Karen Garden ◽  
Lynn M Thomson ◽  
...  
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Young Adult ◽  
Food Intake ◽  
Adult Male ◽  
Dietary Fibre ◽  
Body Weight Gain ◽  
Male Rats ◽  
Decrease Food Intake ◽  
Different Types
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