Scanning-electron-microscopical study of the seminal vesicle, coagulating gland, ampullary gland and ventral prostate in the golden hamster

A study of the internal surfaces of the seminal vesicle, coagulating gland, ampullary gland and ventral prostate of the golden hamster was carried out by scanning electron microscopy. The internal surface of each of these glands was found to display characteristic features in topography and in arrangements of the microvilli. The features are useful in the identification of these glandular tissues in situ.     

Differential proliferative response of the ventral prostate and seminal vesicle to testosterone replacement

We have investigated epithelial cell proliferation and the rate of glandular recovery of the ventral prostate (VP) and seminal vesicle (SV) promoted by testosterone replacement (TR) in castration-induced regressed glands. Adult male Wistar rats were castrated and, after 21 days, they were treated with testosterone propionate (4 mg/kg/day). Intact (CT) and castrated rats without TR (CS) were also analysed. VP and SV were processed for histochemistry, morphometric-stereological analysis and immunocytochemistry to determine the PCNA index (PI). After 10 days of TR, the VP weight reached approximately 72% of the CT values, while the SV weight exceeded approximately 17% of the CT values. By the third day of TR, VP and SV presented a mean PI of 34% and 94% for distal region and 14% and 22% for proximal region, respectively. SV also had more luminal cells PCNA-positive than VP, mainly in the distal region. The PI values fell on days 5, 7 and 10, but were still higher than CT. These findings indicate that epithelial cells from involuted SV are more responsive to TR than those from VP when stimulated to proliferate and replace the luminal cell population, suggesting a different mechanism regulating cell proliferation in response to androgenic stimuli.     

Testosterone and dihydrotestosterone levels in epididymis, vas deferens, seminal vesicle and preputial gland of mice after hCG injection

Temporal changes of testosterone (T) and dihydrotestosterone (DHT) levels were measured by RIA in epididymis, vas deferens, seminal vesicle and preputial gland of adult male mice after a single injection of hCG. The response of circulating T to hCG stimulation was rapid and persisted over a period of 48 h. The temporal changes of androgen content of target organs paralleled the modifications of circulating T. In all organs the high androgen levels attained at 1 or 4 h plateaued until 24 h, decreased thereafter and returned to basal values at 72 h. The concentration of T by sex accessory organs was more accelerated by hCG injection than its conversion into DHT.     

The role of the seminal vesicles, coagulating glands and prostate glands on the fertility and fecundity of mice.

Female mice were allowed to mate with males which had been sham-operated (Group 1); had seminal vesicles, coagulating glands and ventral and dorsal prostate glands removed (Group 2); had the seminal vesicles removed (Group 3); had the coagulating glands removed (Group 4) or had the ventral and dorsal prostate gland removed (Group 5). The pregnancy rate was normal in Groups 1 and 4, severely reduced in Groups 2 and 3 and less so in Group 5. Litter size was reduced in Groups 2 and 3 but not in Group 5. It is suggested that the seminal vesicles and possibly the prostate glands are important in the production of young in mice.     

Effect of oestradiol and tamoxifen on the testosterone response in male rats to a single injection of hCG

A single s.c. injection of hCG (100 i.u.) produced a biphasic serum testosterone response in adult male rats, peaks being noted at 2 h (24 ng/ml) and 3 days (16 ng/ml). The levels fell to control during the intervening interval (8 ng/ml), although there were elevated levels of serum hCG. Maintenance of high oestradiol levels by a s.c. injection of 50 micrograms oestradiol benzoate given on Day 2 after the initial hCG injection failed to prolong the refractory period and the secondary peak of testosterone (16 ng/ml) occurred on Day 3. Administration of the antioestrogen, tamoxifen (2 mg or 3 micrograms), 24 h before or simultaneously with hCG did not prevent testicular refractoriness in vivo because serum testosterone levels still declined after 2 h to reach a nadir at 2 days. The basal in-vitro testosterone production by decapsulated testes from animals injected with hCG was enhanced at 2 h. Stimulation by hCG increased the amount of testosterone produced (X 1.5 that in controls). By 12 h basal production decreased and there was no further increment in testosterone in the presence of hCG. This refractoriness to further hCG stimulation prevailed until Day 3, but the total production of testosterone fell so that at 24 h and 2 days testes were producing basal amounts of testosterone. Testes recovered from refractoriness at 4 and 5 days, when basal and stimulated testosterone production were greater than in controls. Injection of 50 micrograms oestradiol benzoate at 2 days did not prolong the in-vitro refractory period and 2 mg or 3 micrograms tamoxifen had no effect on the in-vitro steroidogenic activity, since testes were still refractory to further hCG stimulation from 12 h to 3 days. The results of the present study do not support the hypothesis that oestradiol is involved in the hCG-induced refractoriness of the Leydig cell. The nadir between the peaks of serum testosterone in vivo corresponds to the period during which the testis is refractory to in-vitro stimulation by hCG.     

Active immunization of boars against gonadotropin releasing hormone. II. Effects on libido and response to testosterone propionate

Of 20 sexually mature Duroc boars showing normal libido, 10 were actively immunized against gonadotropin releasing hormone (GnRH). After immunization against GnRH, boars showed minimal sexual interest in an estrous female, while untreated boars showed normal libido. Eight of the boars actively immunized against GnRH were randomly assigned to treatment (T) or control (C) groups. Boars in the T and C groups were given testosterone propionate or vehicle, respectively, on Days 0, 5, 10, and 15. Boars in both groups were observed for libido in the presence of an estrous female every 4 d for 28 d. Mean libido score for T boars increased gradually until all boars displayed maximum libido on Day 20, but libido returned to low levels on Day 28. In contrast, C boars remained sexually inactive throughout the study. The results of this study indicate that active immunization of sexually mature boars eliminates sexual behavior and that sexual behavior can be restored quickly by administering testosterone propionate.     

Effect of a single administration of testosterone on the immune response and lymphoid tissues in mice.

Female mice were given a single intraperitoneal injection of testosterone immediately after irradiation and marrow reconstitution. Thirty days later testosterone had no suppressive effect on the recovery of thymus and spleen weights. Testosterone had no effect on the graft-versus-host reaction. Testosterone had no influence on the survival of the skin homografts. However, the plaque-forming cell response to sheep erythrocytes in the spleen was dramatically suppressed by testosterone. Histological observations revealed marked inhibition of lymphoid regeneration selectively in the thymus-independent areas of the peripheral lymphoid tissues. These results suggest that testosterone would act mainly on the differentiation of stem cells toward the population of bone marrow-derived B lymphocytes. The immune response to sheep erythrocytes was restored completely 90 days after testosterone administration. Testosterone given to normal adult mice can also have suppressive activity on the immune system 30 days after a single intraperitoneal injection.     

Circadian rhythm and response to an acute stressor of urinary corticosterone, testosterone, and creatinine in adult male mice

In small laboratory species, steroid measures can be obtained more frequently and less invasively from urine than blood. Insofar as urinary levels reflect systemic levels, they could provide advantages particularly for measurement of glucocorticoids, whose blood levels react rapidly to handling and stress. In Experiment 1, urinary samples were collected from male mice every second hour over a 14:10 h light:dark cycle. Samples were analyzed via enzyme immunoassay for corticosterone, testosterone, and creatinine. Corticosterone had peak concentrations 1 h after light offset and a trough 1 h after light onset. Testosterone showed peak concentrations 5-7 h after light onset and lowest concentrations during the dark phase of the cycle. Creatinine showed some variation over the light-dark cycle, but steroid measures showed similar trends with and without adjustment for creatinine. In Experiment 2, mice were stressed via an injection at times close to the determined peak and trough levels of corticosterone. In urinary samples taken 90 min after injection, corticosterone was significantly higher in injected animals at both times relative to levels in control animals, but testosterone was unaffected by injection stress. In Experiment 3, serum and urine samples were collected from mice every sixth hour across the diurnal cycle. Corticosterone peaked in urine and serum immediately after light offset, and urinary measures predicted those in serum. These data indicate that urinary corticosterone reflects systemic levels in mice, document circadian variation in urinary testosterone, and indicate that circadian variation in creatinine is minimal, but potentially relevant in stressed animals.     

Mutations affecting cell division in Tetrahymena pyriformis, syngen 1. II. Phenotypes of single and double homozygotes.

The surface patterns associated with arrest of cell division by temperature-sensitive mutations at five different loci are described. Mutations at the mo1 locus prevent both the subdivision of ciliary meridians that mark the fission zone and the subsequent furrowing. Mutations at mo8 and mo12 cause abnormal configurations in the fission zone and aborted furrowing. Mutations in mo3 and mo6 bring about fission arrest with associated elongation (mo3) or twisting (mo6), even though complete fission zones do develop. The defects in mo1, mo3, and mo12 are expressed in the first division after shift to restrictive temperature, whereas expression of mo6 and of one allele of mo8 are delayed. Following preincubation in an amino acid-free medium at the restrictive temperature, mo8 causes arrest at the first division after readdition of nutrients, while mo6 blocks fission only after one or more divisions at the restrictive temperature. Double homozygotes were constructed containing the mo3^a mutation and mutations at each of the other loci. In addition, mo1^a was combined with mo8^a. In each of the double homozygotes, the characteristic phenotypes of both mutations were simultaneously expressed, and the penetrance of division blockage was very greatly enhanced. The results suggest that the functions of these five loci are not ordered in a single dependent sequence of steps, but rather that these loci probably mediate independent processes required for cytokinesis.     

Developmental changes of hypothalamic, pituitary and striatal tachykinins in response to testosterone: influence of prenatal melatonin.

Substance P (SP) and neurokinin A (NKA), members of the family of mammalian tachykinins, are involved in the regulation of many physiological functions and are widely distributed in mammalian tissues. In this report, the effects of prenatal melatonin on the postnatal developmental pattern of NKA, and SP, and on testosterone secretion were investigated. Also, tachykinin response to the administration of testosterone propionate (TP) was studied. The brain areas studied were medio-basal-hypothalamus, pituitary gland and striatum. Male rat offspring of control or melatonin treated mother rats were studied at different ages of the sexual development: infantile, juvenile or prepubertal periods, and pubertal period. Both groups received exogenous TP (control-offspring+TP and MEL-offspring+TP), or the vehicle (control-offspring+placebo and MEL-offspring+placebo). Hypothalamic concentrations of all peptides studied in control-offspring+placebo remained at low levels until the juvenile period, days 30-31 of age. After this age, increasing concentrations of these peptides were found, with peak values at puberty, 40-41 days of age, then declining until adulthood. In the MEL-offspring+placebo a different pattern of development was observed; hypothalamic concentrations of NKA and SP from the infantile period until the end of juvenile period were significantly higher than in control-offspring+placebo. TP administration exerted a more marked influence on MEL-offspring than on control-offspring and prevented the elevation in tachykinin concentrations associated with prenatal melatonin treatment. TP administration to control-offspring resulted in significantly reduced (P < 0.05) tachykinin concentration only at 40-41 days of age, and increased (P < 0.01) during infantile period as compared to control-offspring+placebo. Pituitary NKA concentrations were lower than in the hypothalamus. In control-offspring+placebo pituitary NKA levels did not show significant changes throughout sexual development. A different developmental pattern was observed in MEL-offspring+placebo, with significantly increased (P < 0.05) pituitary NKA concentrations at 35-36 days of age than in control-offspring+placebo. TP administration to control-offspring influenced pituitary NKA levels at the end of the infantile and pubertal periods, showing at both stages significantly higher (P < 0.05) NKA levels as compared to control-offspring+placebo. NKA levels in MEL-offspring+TP were only affected at 21-22 days of age, showing significantly increased (P < 0.01) values as compared to MEL-offspring+placebo. Striatal tachykinin concentrations in control-offspring did not undergo important modifications throughout sexual development, but during the prepubertal period they started to increase. Maternal melatonin and TP injections produced short-lived alterations during the infantile period. The results showed that prenatal melatonin delayed the postnatal testosterone secretion pattern until the end of the pubertal period and postnatal peptide secretion in brain structures. Consequently, all functions depending of the affected areas will in turn, be affected.     

The influence of hypotonic treatment on the morphology of meiotic stages II. Prophase of the first meiotic division of female mice up to dictyotene

The copy number of the mdg-1 mobile element was determined by biotinylated-DNA hybridization, in salivary gland chromosomes of inbred Drosophila melanogaster larvae from sib progenies. It appears that the lower the egg-to-adult survival (viability), the higher the mdg-1 copy number in the surviving larvae. This suggests a common regulation of the mdg-1 copy number and the viability under inbreeding.