Increased Sperm Production Research Articles

Increased Sperm Production in Adult Rats After Transient Neonatal Hypothyroidism*

In the preceding paper it was shown that transient neonatal hypothyroidism induced by treatment of rats from birth to day 25 with the goitrogen 6-propyl-2-thiouracil (PTU) is associated with increases in testis wt and DNA content of up to 80% during adulthood. The testis changes were accompanied by similar, though less marked, increases in the wt and DNA content of epididymis and accessory organs. The purpose of this study was to assess sperm production in these enlarged testes and measure changes in sperm reserves in the epididymis. Testes and epididymides were obtained from control rats or rats given PTU from birth to day 25 (designated "treated") at 90, 135, 160, and 180 days of age. Daily sperm production (DSP), efficiency of sperm production (DSP/g testis), and epididymal sperm reserves were measured in all animals. Compared to controls, DSP of the treated rats was increased by 83%, 86%, 136%, and 132% at 90, 135, 160, and 180 days, respectively. Thus, in the treated rats, DSP, like testis wt, plateaued at day 160. In addition, efficiency of sperm production was increased by 15%-30% at all ages in treated animals. Epididymal sperm reserves were also increased in treated rats at all ages, but the correlation between DSP and epididymal sperm reserves was weak. Sperm motility and concentration in caudal epididymal fluid of adult males treated from birth to day 25 with PTU were normal. These males were fertile and sired litters in which pup wt and pup number were normal. These results indicate that neonatal hypothyroidism in rats is associated not only with increased testis size but also with increased efficiency of sperm production, resulting in increases in DSP of up to 140% in these animals during adulthood. Maximal sperm production is reached at 160 days of age in treated rats (compared to 100 days in controls), coinciding with the attainment of final testicular size. This system represents the first experimental model in which such large increases in sperm production can be produced. The neonatal PTU treatment does not appear to impair fertility or alter sperm characteristics when these animals become adults and may be a useful system with which to study factors which normally regulate sperm production.

Effects of Coal Leachates on Fish Spermatogenesis

Coal leachates were examined for toxic effects on fish spermatogenesis. Nonbreeding mummichogs, Fundulus heteroclitus, were induced to enter breeding condition in the laboratory by exposure to 20 °C and a photoperiod of 16L: 8D for 6 wk. During this 6-wk period, mummichogs were dosed in static exposure tanks with water extracts of coal (leachates). Chi-square analysis and Z test of proportions revealed a significant reduction in sperm production by fish exposed to some, but not all, coal leachates. This reduction was as much as 40-fold and occurred in a dose-dependent manner. Ordinarily, nonbreeding mummichogs collected immediately after the breeding season will not enter breeding condition in response to 16L: 8D and 20 °C. Exposure of these photo-insensitive mummichogs to coal leachates under long photoperiod conditions for 8 wk resulted in a significant increase in sperm production. Analysis of weekly sperm production by mummichogs from six field populations, either adjacent to or 2 miles upstream from coal-fired power plants, did not reveal significant differences during the breeding season. However, this sperm production was less than 1/10 that of a mummichog field population sampled concomitantly at the Chesapeake Bay Institute. The reduced sperm levels could not be related to reproductive toxin(s) contained in coal leachate.

Male hypogonadotropic hypogonadism: factors influencing response to human chorionic gonadotropin and human menopausal gonadotropin, including prior exogenous androgens.

Although testosterone (T) therapy is sufficient for maturation and maintenance of secondary sex characteristics in hypogonadal men, gonadotropins are required for stimulation of spermatogenesis. Thirteen men with hypogonadotropic hypogonadism received treatment with hCG, followed in 12 by the addition of human menopausal gonadotropin (hMG). All initially had undetectable serum LH and FSH and low T levels and were azoospermic with small testes. During therapy, all achieved normal male levels of T. Twelve of 13 had marked and continuous increase in testicular volume. Three men had sperm in the ejaculate with hCG treatment alone. All but 1 patient developed sperm in their seminal fluid during combined hCG and hMG therapy. Two men achieved three pregnancies, and 2 more had semen that produced hamster oocyte penetration assays in the fertile range during the protocol period. Four of 5 who achieved sperm densities greater than 1 million/ml while receiving combined therapy maintained or increased sperm production while receiving continued hCG therapy after hMG was withdrawn. We examined the response to gonadotropin therapy of men who had received previous T therapy and those who had not. There were no differences in rapidity or degree of response, as assessed by rise in serum T, increase in testis volume, or maximal sperm density achieved. Multiple pituitary deficits and cryptorchidism were negative prognostic factors. In summary, the prognosis for successful stimulation of spermatogenesis in men with hypogonadotropic hypogonadism treated with hCG/hMG is good and not adversely affected by prior androgen treatment. Despite undetectable serum FSH levels, hCG treatment was sufficient to both initiate and maintain spermatogenesis in some patients.

Annual patterns of human sperm production and semen quality.

Mean monthly values for ejaculate volume, sperm density, total sperm count, and percentages of progressively motile, viable, and morphologically normal spermatozoa were calculated from semen analyses performed on the husbands of all couples (excluding cases of azoospermia) referred to an Infertility Service during the years 1975-1979. No significant seasonal variations in any parameter were found. Comparison of the patterns of sperm production with other published studies indicates a tendency for increased sperm production during the late winter and early spring months.

Semen characteristics of Awassi rams

SUMMARYOn the College of Agriculture farm in Abu-Ghraib 147 ejaculates were collected from three docked and four normal Awassi rams born during November 1962. The work covered a period from 1 April 1967 to 31 March 1968.Nine semen characters, namely, volume, mass activity, individual motility, sperm concentration, sperm number, pH, methylene blue reduction time and the percentages of abnormal and dead sperms, were studied. The effect of season and docking on these characters was investigated.Seasonal variation was observed in all traits studied. On the whole, semen quality was poorest during winter and best during summer. The effect of docking was more pronounced on sperm concentration, sperm number and percentage of abnormal sperms. Docking appeared to increase sperm production and reduce sperm abnormality.

Sexual Maturity of Males Representing Twelve Strains of Six Breeds of Chickens , ,

INFERTILE eggs represent an estimated 10 to I5 percent loss of all eggs incubated, Taylor (1949). The influences of temperature, season, and age on fertility in chickens have been investigated by a number of workers. Heywang (1944) reported that high temperature is one important factor influencing the commonly observed summer decline in fertility. Wheeler and Andrews (1943) and Parker and McSpadden (1943), found that season influences spermatozoa production in males. These workers reported an increase in sperm production from December through April and a decline during the summer and fall months.Taylor (1949) suggested the possibility of using cockerels from early spring hatches as breeders to improve fertility during the summer and fall months instead of yearling or older cocks. Jull (1935) compared the fertility of males during their cockerel year and later during their yearling year. He found advantages in favor of the cockerels of 4.85 and 11.1 percent…