Ichiro Ichihara

Ultrastructure and morphometry of testicular Leydig cells and the interstitial components correlated with testosterone in aging rats

The ultrastructure of testicular interstitium in young and aged adult rats was analysed using morphometric methods, and the plasma testosterone concentration was measured. With increasing age there was an augumentation in the volume of collagen fibrils in the intercellular matrix and in blood vessels. During the aging process (approximately two years) the average volume of the Leydig cell decreased from 1364 μm3 to 637 μm3, but the number of Leydig cells in paired testes increased from 53x106 to 113x106. The absolute volume of smooth surfaced endoplasmic reticulum (SER) per Leydig cell amounted in aged rats to 78% of that in young adult rats. The total amount of SER in paired testes increased by 62% with aging. The present analysis suggests that the ability of SER to maintain peripheral testosterone concentration decreases with age. In young adult rats the absolute volume of peroxisomes per Leydig cell correlated significantly with the concentration of testosterone in blood and also with the absolute volume of SER per Leydig cell. These results combined with ultrastructural observations of close apposition of peroxisomes and SER suggest that peroxisomes have a role in testosterone secretion by Leydig cells.

Bone formation by cells from femurs cultured among three-dimensionally arranged hydroxyapatite granules

In vitro bone formation by cells derived from adult rabbit femurs was investigated on or in several substrates with small porous hydroxyapatite granules (HAGs). When the bone fragments were cultured in HAG-packed glass tubes, which were inclined (5 degrees -30 degrees ) and rotated 90 degrees per day after one week of culture, thin lamellar tissues were newly formed in narrow spaces among the HAGs. By 11 days of culture, these tissues had been mineralized except for their periphery and had well developed collagen bundles and several monolayer cells. Some cells resided in bone lacuna-like spaces. By contrast, mineralization was negligible in 6-week cultures on two-dimensional glass and polystyrene plates with or without two-dimensionally arranged HAGs on their surfaces and in three-dimensional collagen gels with or without HAGs in spite of active cell proliferation. These results suggest that osteogenesis is accelerated in a specific three-dimensional constitution of extracellular matrix and/or under the effects of mechanical forces for the new tissue and that bioactive HAGs offer favorable three-dimensional spaces for osteogenic tissue formation.

Light and electron microscopy of the ducts and their subepithelial tissue in the rat ventral prostate

SummaryThe ducts of the rat ventral prostate have been studied by light and electron microscopy for elucidation of their role in prostatic function. The epithelium of the main duct consists of simple columnar cells and polymorphic basal cells. The columnar cells show no indication of secretory activity. The basal cells contain bundles of filaments of 5–6 nm thickness and numerous pinocytotic vesicles. The ducts are surrounded by layers of circular smooth muscle cells interspersed with nerve axons. On ultrastructural grounds the ducts do not appear to secrete material into the seminal fluid, but apparently the muscular coat actively helps drain the gland during ejaculation.

The fine structure of ventral prostatic secretory epithelial cells in older rats

SummaryThe ventral prostatic secretory epithelial cells in older rats were studied by light and electron microscopy. The cells vary in height in different parts of the same organ, and ultrastructurally they show the presence of a developed secretory apparatus such as well-developed Golgi body and abundant rough endoplasmic reticulum. They also show signs of a depressed secretory activity, involving occasional emiocytosis of apical secretory vacuoles and a paucity of condensing vacuoles in the Golgi region and above it. Further, they are characterized by the frequent occurrence of supra and paranuclear pleomorphic lysosomes.

Some ultrastructural effects of testosterone and insulin on the ventral prostate of rats in organ culture

SummaryThe fine structure of the secretory epithelial cells of rats ventral prostate has been studied following organ culture. Culturing with either testosterone or insulin alone, and with the two hormones combined, were carried out to investigate how insulin modifies the action of testosterone on the maintenance of cellular integrity. After 4 days in hormone-free culture, the secretory epithelial cells showed signs of cellular atrophy and regression, involving loss of the apical microvilli, absence of the apical secretory vacuoles, atrophy of the Golgi apparatus, decrease in rough endoplasmic reticulum and the appearance of autophagic vacuoles. The presence in the medium of either testosterone or insulin alone, or combined, prevented cellular atrophy and regression. The best maintenance of cellular integrity was obtained in a culture containing both hormones. The effects of insulin was approximately equivalent to those of testosterone in the maintenance of cellular integrity.

Stereologic and fine-structural studies of prostatic acinar basal cells in the dog.

SummaryThere are two distinct types of epithelial cells in the lining of the glandular acini of the prostate in adult male Beagle dogs, i.e., the columnar secretory epithelial cells and the basal cells. In contrast to the secretory epithelial cells, basal cells exhibit an abundance of micropinocytotic vesicles on their basal surface. Blood capillaries are often found in the stromal tissue in close proximity to these cells and their walls frequently display chains of fenestrations bridged by diaphragms.Stereological analysis shows that the volume density of the basal cells in the reference volume of acinar parenchyma is 0.056, and there are approximately 132.14 million cells per cm3 of prostatic tissue. An average basal cell has a volume of 373.5 μm3, and the volume densities of its nucleus, rough endoplasmic reticulum, Golgi apparatus, mitochondria and micropinocytotic vesicles, are 0.49, 0.04, 0.04, 0.094 and 0.013, respectively. These data are distinctly different from those that have been reported for the prostatic secretory epithelial cells of the same animals.

Morphological changes in mouse accessory sex glands following neonatal estrogen treatment.

A single injection of beta-estradiol 17-cypionate into the mice within 5 hr after birth induced inflammation in all prostate lobes and the seminal vesicles. Neutrophils emigrated into the lumen through the basal lamina and epithelium of the seminal vesicle and the anterior prostate. Local infiltration of lymphocytes was observed in the stroma and epithelium of ventral prostates. Lymphocytes penetrated through smooth muscle cells into epithelium. This could support the hypothesis that smooth muscle cells are the target of the estrogen action of prostates in estrogenized animals.

The effect of androgen and estrogen on secretory epithelial cells and basal cells of the rat ventral prostate after long-term castration

After long-term castration, rats were injected with cotton seed oil, testosterone- and estradiol-17 beta-cypionate (CS, TC and EC). The height of the epithelial cells of the ventral prostates from the castrated rats increased after TC and EC-injection. The secretory and basal cells formed two layers of epithelium, an inner layer near the lumen with pale nuclei and another layer with dark nuclei. These two layers could result from a reduction of secretory epithelial cells. Castration decreased the ratio of secretory cells to basal cells (S/B). TC-injection increased the ratio of S/B because of the secretory epithelial cell growth. Longer dark cells may be transient cells, appearing during the differentiation of basal cells into secretory epithelial cells. A sheet branching off from the basal lamina was observed. Androgen may stimulate the synthesis of the lamina, but whether it induces the synthesis or turnover of the basal lamina has not been established. EC increased the ventral prostatic weight and secretory epithelial cell height and induced the appearance of crystalline granules. Increase in S/B ratio may result from an increase in the secretory epithelial cells, but not from basal cell multiplication due to squamous metaplasia. The ratio is significantly correlated to the weight of the ventral prostate, but not to the secretory epithelial cell height. Its value could indicate the multiplication of secretory epithelial cells, differentiation of basal cells into epithelial cells, or both. It is probable that basal cells do not change in number, but control the size of the rat ventral prostate in response to the hormone level.

Light and electron microscope histochemistry of alkaline phosphatase in the ventral prostate of rats

Alkaline phosphatase was studied in the ventral prostate of rats by light and electron microscopy. In light microscopy, the enzyme activity was found in the luminal secretion and also on the luminal edge of the acinar walls as well as in the basal area of the acinar walls. It was also found in the walls of periacinar blood capillaries. The enzyme activity was abolished with addition of either L-phenyl-alanine or L-homoarginine and also of L-tartaric acid into the incubating medium. In electron microscopy, the enzyme activity was observed in the luminal secretory material and further it was observed strongly in the sharply localized pittings of apical surface of acinar secretory epithelial cells. The lower lateral and basal surface of the cells showed presence of rather weak activity of the enzyme. The basal cells showed strong activity of the enzyme in pinocytotic vesicles. Further, intense activity of the enzyme was observed on the cell surface of the fibrocytes immediately surrounding acinar basal lamina and also in pinocytotic vesicles of periacinar blood capillaries.

Morphometry and Ultrastructure of Stage IX-Specific Effects on Rat Sertoli and Spermatogenic Cells Immediately After 7-Day Testosterone Treatment in One Group and the Same Treatment in Another Group Followed by 7-Day Non-Treatment

Purpose: In our previous study, morphometric and ultrastructural analysis of stage-specific effects of Sertoli and spermatogenic cells were seen immediately after 7-day testosterone treatment (T group) in rat testes. The results strongly suggested that significant regulatory factors in spermatogenesis remain to be discovered. The present study was conducted to determine the morphometric and ultrastructural analysis of rat sertoli and spermatogenic cells in stage IX T group in one group and the same treatment in another group followed by 7-day non treatment (AT group), and also to assess whether or not the suggested unknown regulatory factors exist in the AT group. Results: In the AT group, concentrations of testosterone decreased more prominently than in its counterpart in the T group. However, its concentration was lower than its counterpart in the control group of rats. Both luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the AT group increased significantly more than their counterparts in the T group. Further they were closer to their counterparts in the control group than their counterparts in the T group. The absolute volumes of seminiferous tubules in the AT group increased to levels closer to their counterparts in the control group than to their counterpart in the T group. In the cytoplasm of the Step 9 spermatid in the T group, disorganization of the microtubules in a manchette-like structure appeared. However, they assumed a normal manchette-like orientation in the AT group. The fine structures corresponding to the transverse section of tails in normal spermatozoa were detected in the adluminal region of the seminiferous epithelium in the AT group, and these findings suggest that normal spermatozoa were formed in the AT group. Conclusion: The present study strongly suggests that unknown regulatory factors remain to be discovered.