Andrzej Bartke

Effect of ethyl alcohol on plasma testosterone level in mice

Abstract The effect of ethanol ingestion on testicular steroidogenesis in mice was evaluated by measuring plasma testosterone level. Four groups of CBA/J male mice were treated with one of the following doses of ethanol: 1.240, 0.620, 0.310 or 0.155 g ethanol/Kg body weight. A control group was given water. The data showed no effect of the treatment on testicular weight. The concentration of testosterone in the plasma was significantly reduced in animals treated with alcohol. There was also a significant relationship between the dose of alcohol and the plasma testosterone level, with the decrease in testosterone being from 2 to 18 fold in various groups.

Suppression of testosterone production by ethyl alcohol. Possible mode of action

Intragastric administration of ethyl alcohol (1.24 g/kg body weight) to adult male mice caused a drastic decrease in the concentration of testosterone (T) in peripheral plasma. The depression of plasma T levels was significant at 30, 60 and 90 minutes after alcohol administration, but by 120 min, the normal T levels were re-established. This transient decrease in peripheral T levels was probably due to a reduction in testicular T production, because at 1 hr after alcohol administration, the concentration of T in the testis was also significantly depressed. The ability of the testes of alcohol-treated mice to produce T in response to gonadotropic stimulation in vitro was not affected. Addition of 5, 10, 20 or 50 microliter of alcohol per ml of the medium used for the incubation of decapsulated testes had no significant effect on the accumulation of T, but similar doses of acetaldehyde caused a pronounced inhibition of T production. The decrease in plasma T levels observed after administration of ethyl alcohol in vivo may be related to a direct inhibition of testicular T production by acetaldehyde derived from the metabolism of alcohol.

Direct and pituitary-mediated effects of Δ9-THC and cannabinol on the testis

Abstract In mouse testes incubated with hCG, addition of Δ 9 -tetrahydrocannabinol (THC) resulted in a significant inhibition in the accumulation of testosterone (T) and progesterone. The concentrations of 17α-OH progesterone, androstenedione, and estradiol were not changed. The inhibition of T production in this in vitro system by THC was dependent upon the presence of hCG in the medium, suggesting that THC may interfere with gonadotropin stimulation of testicular steroidogenesis. In contrast, suppression of T secretion by cannabinol (CBN) also occurred in the absence of hCG. In the in vivo studies, administration of a single oral dose of THC to adult male mice resulted in a reduction in plasma T, LH and FSH levels, as well as an increase in the concentration of esterified cholesterol in the testis. In contrast, a single dose of CBN produced no significant changes in either plasma T or gonadotropin levels. Treatment with THC, but not with CBN, resulted in a pronounced reduction in the level of copulatory activity in adult male mice. It appears that the THC-induced reduction in plasma T levels observed in vivo is due to an inhibition of pituitary LH release, and to a direct effect on the testicular responsiveness to LH stimulation. The reduction in copulatory behavior observed after acute exposure to THC may be secondary to a reduction in peripheral T concentration.

Evidence for episodic secretion of testosterone in laboratory mice.

The concentration of testosterone (T) in the peripheral plasma of laboratory mice is extremely variable. This variability is already evident at 20--25 days of age and is not eliminated by brief or chronic exposure to male or female mice, or by isolation. The variation in T levels in plasma samples collected from the same animals on different occasions is comparable to the variation between individuals bled on a single occasion. The concentration of T in the testis is as variable as that in the peripheral plasma. It is suggested that in the laboratory mouse T is produced and released in an episodic fashion, that elevations in T levels in peripheral plasma of mice are greater than those observed in other species, and that testicular secretory episodes are interspersed with periods of minimal steroidogenic activity.

Influence of photoperiod and gonadal steroids on hibernation in the European hamster

SummaryTorpor was monitored daily in adult male and female European hamsters (Cricetus cricetus) induced to hibernate by exposure to a cold environment (6 °C). The effect of photoperiodic manipulations or administration of exogenous gonadal steroids was examined in gonadectomized or intact hamsters.1.Gonadal regression occurred in all short day, but only in some long day, cold-exposed hamsters. Entry into hibernation was not observed until reproductive regression had occurred. Thus, gonadal atrophy appears to be a necessary precondition for hibernation.2.Castrated hamsters in the short day cold condition showed a significantly greater incidence of torpor than those in the long day cold condition. Hence, photoperiod affected torpor independently of its effect on the gonadal cycle.3.Testosterone, when administered via silastic capsules at near physiological levels, completely inhibited torpor in gonadectomized male and female hamsters hibernating in the short day cold condition.4.In ovariectomized females, torpor was unaffected by progesterone treatment, but partially inhibited by estradiol. A greater inhibition of torpor was observed when estradiol-primed females were administered both estradiol and progesterone simultaneously. Thus, the effect of both hormones may be functionally comparable to that of the single testicular hormone.5.Estradiol inhibited torpor to a greater extent in intact and ovariectomized female hamsters hibernating in long days than those in short days, suggesting an effect of photoperiod on responsiveness to estradiol. These results indicate an inverse relationship between the gonadal and hibernation cycles, and a probable role for gonadal steroids to influence the timing of the hibernation season. However, non-gonadal factors must also be involved in controlling hibernation, since photoperiod affected the incidence of torpor in gonadectomized animals and because hamsters were able to terminate hibernation in the absence of gonadal hormones.

Prostaglandins inhibit testosterone secretion by mouse testes in vitro

Production of testosterone (T) by decapsulated mouse tests in vitro was significantly inhibited by adding prostaglandin (PG) A1, PGA2 or PGE1 to the incubation medium. Prostaglandin A1 at a concentration of 10(-6)M inhibited T production in this system both in the presence of moderate amounts of hCG (12.5 or 25.0 mIU/ml), and in the absence of gonadotropins. However, in the presence of very high levels of hCG (125.0 mIU/ml), all PGs tested appeared to have had a slight potentiating effect on T production when added in concentrations ranging from 10(-7) to 10(-5)M, and the inhibition of T accumulation in the medium was consistently observed only when the concentration of PGs was increased to 10(-3)M. These results suggest that a direct effect of PGs on testicular steroidogenesis may account for, or contributes to, the decrease in peripheral T levels observed after administration of PGs in vivo.

Individual differences in the maternal behavior of male mice: no evidence for a relationship to circulating testosterone levels.

Abstract Maternal behavior toward newborn pups and endogenous levels of testosterone (T) in peripheral plasma were measured in individual adult male mice. Separate groups of animals that either retrieved, ignored, or killed pups were found not to differ with respect to plasma T levels, body weights, or relative weights of testes, seminal vesicles, and adrenals. Furthermore, animals do not exhibit changes in T following tactile or nontactile interactions with pups.

Aminoglutethimide inhibits steroidogenesis in the rat testis

A study was conducted to examine the effects of aminoglutethimide on plasma testosterone levels concentration of free and esterified cholesterol in the testis and weight of sex accessories in male rats. Adult male rats were injected with 10 mg or 15 mg aminogluthethimide phosphate (AGP) per 100 gm body weight twice daily for 3 1/2 days and killed 3 hours or 5 hours after the last injection. The weights of the seminal vesicles and the prostates appeared reduced in all treated animals but only the effect of the higher dose of AGP on seminal vesicle weight was statistically significant(pl.05). (p less than .05). concentration of testosterone in the plasma was significantly reduced 3 hours after the injection of either dose of AGP and 5 hours after the injection of the higher dose. There were no changes in the weight of the testes or in the concentration of free cholesterol but the concentration of esterified cholesterol was increased in rats given the higher dose of AGP. The difference between these and the control animals was significant in the group killed 3 hours after the last injection and also when animals killed 3 and 5 hours after the last injection were combined. The results indicate that aminoglutethimide inhibits testicular steroidogenesis.

Juvenile male mice: An attempt to accelerate testis function by exposure to adult female stimuli

Abstract Two experiments were conducted in order to determine whether juvenile male mice show accelerated maturation of testis function following chronic exposure to adult female mice. Experiment 1 showed that the maturation of testis function, as measured by radioimmunoassay of plasma androgens in post-weaning group-housed (6/cage) male mice, is most rapid between 22 and 42 days of age with peak androgen levels attained by 42 days of age. Experiment 2 showed that juvenile males exposed to an adult female through a wire mesh partition from 22 to 32 days of age show accelerated growth of an androgen-dependent accessory organ, the seminal vesicles, when compared to males housed either in direct contact with an adult female, in isolation or in groups of 2 or 6. The absence of dense housing conditions (i.e., juvenile males housed in isolation or pairs) promoted, whereas social conflict (i.e., juvenile males housed in direct contact with an adult female) and dense living conditions (i.e., juvenile males housed in groups of six) inhibited, the growth of the seminal vesicles. Because plasma androgens were unaffected by the differential housing conditions, it was speculated that the pulsatile pattern of androgen release in the mouse may have obscured possible group differences in circulating hormones.

Biliary metabolites of 14C-estrone and 14C-estradiol from the rat☆

Abstract Estrone, 2-hydroxyestrone, 2-methoxyestrone, 2-hydroxyestrone 3-methyl ether, estradiol-17β and 2-hydroxyestradiol-17β have been identified as biliary “glucuronide” metabolites of radioactive estrone and estradiol from the rat. 2-Hydroxyestrone vas conjugated at the 2 position. This is the first report of an in vivo conversion of estrone and estradiol to 2-hydroxyestrone 3-methyl ether.