Changes In Scrotal Temperature Research Articles

Semen quality and sedentary work position.

Increased scrotal temperature can, in experimental settings, markedly disturb the production of semen. Sedentary work position may increase the temperature of the scrotum, but previous studies have failed to determine whether changes in scrotal temperature caused by sedentary work actually do affect semen quality. This study was carried out to elucidate the possible harmful effects of sedentary work on sperm count and other semen characteristics. In 1981-1983 a semen sample was obtained from 3119 men who attended an infertility workup in one of four Danish fertility centres. A total of 2517 men returned a postal questionnaire with information on life style, leisure time activities, occupational history and job duties. Information on job specific work position was obtained from The Danish Work Environment Cohort study 1990 (DWECS). In this analysis DWECS data for a total of 1747 men was included from men aged 18-39 years with >30 h of work per week. For all job titles represented in the DWECS, the mean proportion of sedentary work was estimated. The sperm cell concentration was 30.6 million/mL among men in the quintile with lowest job specific sedentary work compared with 40.5 million/mL in the highest quintile. The difference was, however, not statistically significant. Stratification on infertility period, educational level of the man, fertility centre, and fertility-related disease of the spouse did not influence the results. The analyses do not suggest that sedentary work is a risk factor for abnormal semen characteristics.

Effects of testicular biopsy in clinically normal bulls.

To determine whether testicular needle biopsy is detrimental to testicular function in clinically normal bulls. Prospective study. 6 mixed-breed mature bulls. A randomly selected testicle from each bull was biopsied with a 14-gauge needle biopsy instrument. Bulls were then evaluated over a 90-day period for changes in scrotal temperature and thermal patterns, ultrasonographic appearance, and quality of spermatozoa. At the end of the 90-day study, bulls were castrated, and testicles were examined grossly and histologically. Changes were detected in scrotal temperatures and thermal patterns and in the breeding soundness examination results during the first 2 weeks of the study. However, there were no long-term changes in semen quality over the course of the experiment. Hyperechoic areas were detected on ultrasonographic examination and corresponded to the areas of penetration by the biopsy instrument. Microscopic lesions that were indicative of testicular dysfunction were not found. Results indicate that testicular biopsy is a safe procedure in bulls. Testicular biopsy could possibly be used to further examine bulls that have less than satisfactory results for breeding soundness examinations.

Neuronal activity changes of ventromedial hypothalamic neurons and associated temperature responses in rats following scrotal thermal stimulation.

Experiments were conducted to determine whether ventromedial hypothalamic (VMH) neurons were responsive to thermal warming or cooling of the scrotum. Extracellular neuronal activity of VMH neurons was monitored in anesthetized groups of normothermic (core temperature maintained at 37 degrees C) or hypothermic (core temperatures allowed to decrease, 33.3 +/- 1.1 degrees C) male, Sprague-Dawley rats along with colonic (Tc), interscapular brown adipose tissue (TIBAT), tail (Tt), and scrotal (Tsc) temperatures during 30-min periods of scrotal cooling (small ice peak) or scrotal warming (small sealed pack containing 40 degrees C tap water). In the normothermic group (65 VMH neurons recorded in total), 20 VMH neurons (31%) were classified as warm-responsive neurons (WRNs) (i.e., increased firing rate with scrotal warming and (or) decreased firing rates with scrotal cooling); 7 VMH neurons (11%) were classified as cold-responsive neurons (CRNs) (i.e., increased firing rate with scrotal cooling and (or) decreased firing rate with scrotal warming); and 38 VMH neurons (58%) were thermal nonresponsive neurons (TNRNs). In the hypothermic group (total of 85 VMH neurons recorded), 14 neurons (16%) were WRNs, 15 neurons (18%) were CRNs, and 56 neurons (66%) were TNRNs. Results indicated that VMH neurons can respond selectively to changes in scrotal temperature, as previously shown for preoptic-anterior hypothalamic neurons. Scrotal cooling and warming caused marked changes in T(sc) values in both the hypothermic and normothermic rats, but significant increases in TIBAT values indicative of brown adipose tissue thermogenesis did not occur.

Effect of changes in scrotal temperature on food intake in pigs

1. 1. Temperature of the scrotum or a similarly sized area of skin on the back of young pigs was changed by means of a thermal pad and food intake was measured. 2. 2. Warming the scrotum to 42°C significantly increased food intake in pigs reared and fed at 25°C. 3. 3. Cooling the scrotum to 20°C, or changing the back skin temperature had no effect on food intake. 4. 4. Acclimation to 10°C, or exposure to 10°C for 4 hr before a meal resulted in an increase in food intake. 5. 5. Warming the scrotum did not affect this cold-induced increase in food intake. Warming the scrotum, but not the skin on the back, reversed the meal-induced increase in rectal temperature. 6. 6. It is concluded that changes in food intake observed during wanning the scrotum were not a direct result of the sensory information signalling increased skin temperature. 7. 7. The likely mechanisms involved are the interactions of peripheral and deep body temperature, decreased deep body temperature and increased heat loss.

Threshold temperatures of diencephalic neurons responding to scrotal warming

Neurons in the rat's thalamus and hypothalamus abruptly change their firing rates from minimum to maximum, or vice versa, with increase in scrotal temperature of 1 degree C or less ("switching response"). The threshold temperature of the switching response was compared in pairs of neurons simultaneously recorded from the right and left thalamus or from the right thalamus and the left hypothalamus. In dynamic conditions in which scrotal skin was gradually warmed at rates of 1-7 degrees C/min, the threshold temperatures of each neuron pair differed by only 0.4 degree C or less. The threshold temperatures of static responses of each pair of neurons, which was determined with step changes in scrotal temperature, fell in a range less than 0.8 degree C. Scrotal warming produced desynchronization of cortical EEG which was monitored during unit recordings. The change in EEG occurred at about the same scrotal temperature at which the switching responses of the diencephalic neurons were elicited.