Volume Of Interstitial Tissue Research Articles

Reproductive Cycles of Teiid Lizards in Amazonian Savanna

-Ameiva ameiva, Cnemidophorus lemniscatus, and Kentropyx striatus reproduce seasonally in Amazonian savanna near Alter do Chao, Brazil. Most egg deposition occurs during the wet season but most development of gonads and growth of juveniles occur during the height of the dry season. Relative fat-body size varies little throughout the year and there is no apparent correlation between fatbody size and gonad development. Reproductive cycles of reptiles in seasonal tropical climates have been considered to be correlated with rainfall, most egg deposition occuring during the wet season (Fitch, 1982). However, recent work indicates that the reproductive cycles of tropical lizards show great variability and that reproductive cycles are not always tightly linked to rainfall patterns (Vitt, 1986). Variation in the availability of food is generally given as the reason for cycles. On the other hand, Stamps and Tanaka (1981) have shown that the availability of water may limit the growth of Anolis aeneus independent of the effects of food availability, and Rose (1982) found that supplemental feeding increased fat stores but not reproduction in Anolis acutus. Dunham and Miles (1985) suggest that phylogenetic constraints and biogeographic history may have played major roles in shaping squamate reproductive patterns. James and Shine (in press) suggest that, in northern Australia, lizard species reproduce in the season (wet or dry) that most closely simulates climatic conditions where their antecedents evolved. The data base is insufficient to define clearly the reproductive patterns of lizards from seasonal tropical environments. Here I present data on the reproductive cycles of three sympatric species of teiid lizards (Cnemidophorus lemniscatus, Ameiva ameiva, and Kentropyx striatus) which occur in Amazonian savanna. Seasonal variation in interstitial testicular tissue (Del Conte, 1972) and testis volume (Leon and Cova, 1973) has been reported for Venezuelan C. lemniscatus but female C. lemniscatus with oviductal eggs were found in the garden of the Universidad de Orient en Cumana in most months (Leon and Cova, 1973). Ameiva ameiva in rainforest habitat in Ecuador have strongly seasonal reproduction (Simmons, 1975) but A. ameiva in the arid caatinga of northeastern Brazil breed continuously and show only weak seasonality which is not directly related to rainfall (Vitt, 1982). I know of no studies of the reproductive cycle of K. striatus. Reproductive cycles can be inferred from: (1) longitudinal studies of individual animals; (2) gonadal cycles of males and females; (3) population age structure; (4) the presence of eggs or neonates in the population; or a combination of all four lines of evidence. In this study I present data on aspects (2), (3), and (4) for Cnemidophorus lemniscatus, (3) and (4) for Ameiva ameiva, and (4) only for Kentropyx striatus. During a previous study (Magnusson et al., 1985) we noted that the mean clutch size differed between C. lemniscatus collected in the savanna and on freshwater beaches. The densities of C. lemniscatus in these two habitats also differed significantly (Magnusson et al., 1986). I therefore collected data on possible population differences between habitats for that species. Fat-body cycles are often closely related to reproductive cycles in temperate lizards (Derickson, 1976). However, there may be less relationship between fat-body cycles and reproduction in tropical lizards (DerThis content downloaded from 157.55.39.104 on Sun, 19 Jun 2016 06:07:10 UTC All use subject to http://about.jstor.org/terms WILLIAM E. MAGNUSSON 7 5 7 3 2 7 4 A e. /-Reproductive A Ameiva / /GArovid

Stimulatory effect of follicle-stimulating hormone on rat Leydig cells. A morphometric and ultrastructural study.

The effects of FSH on the testicular interstitial tissue of immature hypophysectomized rats were studied by comparing morphological changes in Leydig cells with quantitative changes in interstitial tissue histology using morphometric analysis. Three groups of rats received subcutaneous injections of 0.5 ml saline vehicle or 10 micrograms rFSH or 20 ng oLH (equivalent to the amount of LH known to contaminate the FSH), twice daily for 7 days. Administration of FSH significantly increased testis weight and stimulated more advanced spermatogenesis compared to saline or LH. Morphometric analysis of testes of LH-treated rats showed a small but significant increase in total interstitial cell volume compared to saline treatment. FSH caused much greater increases in the total volume of interstitial tissue and interstitial cells than either saline or LH and significantly increased the total volume or interstitial fluid by comparison with the other groups. FSH but not saline or LH treatment resulted in a striking hypertrophy of Leydig cells, to produce cells ultrastructurally identical to Leydig cells from adults. Since the target tissue of FSH is the seminiferous epithelium, the observed effects on Leydig cells by FSH treatment suggest that the secretion of factors by the seminiferous tubules may mediate the maturation of Leydig cells.

Tissue stereologic analysis of myocardial atrophy during hypokinesia

The myocardium of Wistar rats which were in a state of hypokinesia for 5, 15 and 30 days was assayed morphologically. Morphometric and stereological methods were used to measure the diameter of cardiomyocytes, the volume and surface densities of muscle fibers and interstitial connective tissue. Myocardial atrophy (absolute heart weight loss, reduction in the cardiomyocyte diameter) was shown to develop in the course of hypokinesia. Informational analysis revealed the increased enthropy and relative enthropy as well as reduction of excess myocardial tissue. Long-term immobilization also resulted in an increase of the relative volume density of the stroma, collagenization of the interstitial connective tissue, and marked tendency toward diminution of the surface-volume ratio of the capillaries.

Morphometric studies in undescended testes

The volumetric fractions (VF) of various types of testicular tissue and the mean tubular diameter (MTD) were determined in biopsies from 134 cryptorchids aged 3.5-16.9 years and in a normal material (67 autopsies). In the normal group VF of spermatogonia A was relatively stable in all age groups, whereas VF of the total spermiogenesis increased sharply after 10 years. In the patients the mean values of both these parameters were markedly decreased in all age groups. VF of tubular tissue was relatively stable in childhood and increased after 10 years both in the normals and the patients. In the youngest patients the testicular volume, the volume of tubular tissue per testis, and MTD were decreased whereas the volume of interstitial tissue per testis was normal. After 10 years of age MTD was decreased in the patients. None of the parameters investigated showed significant differences between cases with high (intraabdominal and canalicular) and low retention. The results indicate that reduction of the spermatogonial and Sertoli cell lines are present in retained testes from 3.5 years of age. At puberty the maturation of tubular tissues is inhibited in untreated retained testes.

Ultrastructural and histochemical studies on the testis of the river lamprey, Lampetra fluviatilis (L.).

SUMMARY The structure of interstitial cells and the cells of the lobule wall was studied in the lamprey testis throughout the period of sexual maturation. In the course of their secretory cycle the interstitial cells showed the usual characteristics of vertebrate steroidogenic tissues; a well-developed agranular reticulum, mitochondria with a dense matrix and tubular cristae, and lipid inclusions. Similar characteristics were also seen in the cells of the lobule wall in the period immediately preceding spermiation. In the interstitial cells, hydroxysteroid dehydrogenase (HSD) activity reached a maximum in late January and February, in advance of the development of the secondary sex characteristics, and was correlated with the abundance of interstitial lipid. After hypophysectomy, no changes were detected in the numbers or volume of interstitial tissue, and HSD activity was apparently unaffected. Characteristic multivesiculate bodies were not observed in the cells of the lobule wall in hypophysectomized animals.

Estradiol-17-beta, progesterone and 20-alpha-hydroxypregn-4-en-3-one in rabbit ovarian venous plasma. I. Steroid secretion from paired ovaries with and without corpora lutea; effect of LH.

Estradiol-17β (E2) secretion in rabbits was measured in the ovarian venous blood by a radio-ligand binding procedure. Mean E2 secretion in 6 estrous rabbits studied was 17.7 ± 1.71 μg/ovary/hr. Levels of E2, progesterone and 20α-hydroxypregn-4-en-3-one (20α-OH) in the ovarian effluent of pseudopregnant and pregnant rabbits, each having one ovary with and one without corpora lutea (CL), indicated that estrogen secretion was independent of the CL or the volume of interstitial tissue. Estrogen secretion was not altered by acute administration of ACTH, but a single small injection of LH (0.5 μg/kg iv) induced an immediate increase in the output of E2, progesterone and 20α-OH. It is concluded that the follicle constitutes the sole source of ovarian E2 in the rabbit, and that physiological levels of LH stimulate estrogen release. (Endocrinology 89: 105, 1971)

CYCLIC CHANGES IN INTERSTITIAL GLAND TISSUE OF THE HUMAN OVARY.

AbstractThree distinct types of gland cells occur in adult human ovaries and those of other mammals. These are: (1) Interstitial gland cells formed from the theca interna cells of degenerating (atretic) follicles, hence present from infancy to old age; (2) Thecal gland cells formed from the theca interna cells of ripening follicles, hence present only in individuals that are sexually mature or nearly so, and in these only at or near the time of ovulation; (3) Luteal cells formed from the granulosa cells of ovulated follicles and from the undifferentiated stroma cells surrounding these, and in certain species also from the same sources in relation to atretic follicles. These latter are the so‐called accessory corpora lutea. Primary and accessory corpora lutea are present normally only after ovulation occurs and appear to function for a relatively short time unless pregnancy ensues. In certain species other types of gland cells occur in the ovary and mesovarium; these include the paraluteal cells of the human ovary. Paraluteal cells are not persistent thecal gland cells, but are differentiated from surrounding stroma after the thecal gland disappears. They are probably intermediate stages in the differentiation of luteal cells from stroma cells. Planimetric measurements and computations made from serial sections of human ovaries indicate that in non‐pregnancy and early pregnancy the volume of interstitial gland tissue is less than 1% of the total ovarian volume. However, in the last trimester of gestation, the relative amount of interstitial gland tissue increases rapidly to roughly from 4% to 6% of the total ovarian volume. The largest amount in our series was 5.6%. Luteal gland tissue at the height of its development in the first trimester of gestation reached 31% of the total ovarian volume. In human ovaries the cells of the interstitial gland tissue of late pregnancy seem to be consistently larger and to have a more finely granular cytoplasm than those of early pregnancy or nonpregnancy. The literature shows that mammalian interstitial gland cells of comparable origin to the human cells discussed in this paper have the following characteristics which are known to be indicative of steroid secretors: Numerous birefringent, acetone soluble, autofluorescent granules which react with sulphuric acid and are Schultz and Schiff positive; mitochondria with anastomosing tubular cristae; and smooth tubular endoplasmic reticulum. Physiological studies so far reported have indicated possible estrogen, androgen, and progesterone production by interstitial gland cells, but all of the evidence is too scanty, indirect, and at times contradictory to be convincing. Since interstitial gland cells are present from birth to old age, and show cycles of abundance and differentiation correlated with the reproductive age and cycles, they may prove to be the most important ovarian gland cells when their function is fully understood.

Esterase substrate specificity in the testis of the growing mouse

The age distribution of esterases in the interstitial cell of the mouse testis was studied between birth and the end of the tenth week of postnatal life by using the substrates O-acetyl-5-bromoindoxyl, α-naphthyl acetate, naphthol AS acetate, naphthol AS-LC acetate, and naphthol AS-D acetate. With indoxyl acetate, esterase activity is prominent at birth and wanes over the first 2 weeks of postnatal life. Esterase activity with the substrates αnaphthyl acetate, naphthol AS acetate, and naphthol AS-LC acetate is first demonstrable 2, 3, and 7 weeks after birth respectively, and in each instance increases steadily with age. Differences in the volume of reactive interstitial tissue for each of these substrates are demonstrable at all ages. Naphthol AS-D acetate is only utilized by the interstitial cells of the 10-week mouse. No esterase substrate is used by all age groups, and quantitative differences at a given age exist between the individual substrates. These results are thought to imply the existence of at least 5 substrate-specific esterases in the mouse interstitial cell, and their possible relation to steroid synthesis is noted.

Reproduction in some Pinnipedia.

Summary. The reproductive organs have been described in a series of seals, including foetal, neonatal and adult specimens. The collection includes seals from the Antarctic, European waters and from the North Pacific. The species are:—Leptonychotes weddelli, Lobodon carcinophagus, Hydrurga leptonyx, Phoca vitulina, Halichoerus grypus, Otaria byronia. Zalophus californianus, Eumetopias stelleri, and Callorhinus ursinus. The gross and histological appearances of the testis are described. There is evidence of a breeding season and cyclic testicular activity in the Wed dell and Crabeater Seals. Some measurements of the os penis are given. A description is given on the gross anatomy of the urinogenitai tract in the female. The ovarian bursa is much enlarged during pregnancy. The urinary papilla is large, partly owing to the presence of lymphoid tissue. Unimplanted blastocysts have been found in the Crabeater Seal at a time that confirms the occurrence of delayed implantation. Other evidence suggests that delayed implantation is universal in most, if not all, seal. In at least two species, the Grey and Common Seals, there is marked enlargement of the late foetal and neonatal gonads to a size near or surpassing that of the maternal gonads. This enlargement is primarily due to an increase in the volume of interstitial tissue. Invaginations of the epithelium forming sub‐surface crypts have been observed in all species of pinniped examined. There is evidence of cyclical activity in the number and development of these crypts. Their relationship to oogenesis is discussed. The changes in the corpus luteum are described during early and late pregnancy. During the period of delay in implantation the majority of the luteal cells are heavily vacuolated. The changes in the uterus and vagina are correlated with the changes in the ovary, both in the foetal, neonatal and adult. Coiling of the uterine glands and secretory activity is found in the neonatal specimens. A short note is appended on the foetal membranes.

Seasonal cycles of the interstitial cells in the testis of the horned toad (Phrynosoma solare). Seasonal variations in the number and morphology of the interstitial cells and the volume of the interstitial tissue

AbstractA histological study has been made of a series of Phrynosoma testes taken at frequent intervals throughout the year. As it was important to differentiate between the amount of interstitial tissue and the number of cells, it was necessary to take into account the percentage of tissue, total testis volume and the number of cells per unit volume.The results show a definite interstitial‐cell cycle. Volume of interstitial tissue and size of individual cells are greatest during the breeding season, but the interstitial‐cell number is then minimal. The maximal number of interstitial cells occurs after the close of the breeding season. There is, apparently, no reversion of interstitial cells to a connective‐tissue‐cell type.The above changes are correlated with the spermatogenetic cycle and with increases in total tubule length, in tubule diameter, and in testis volume. The time in which important changes in ovarian volume occur and at which ovulation takes place is coincident with the testicular changes.Interstitial cells have been stated to have no endocrine function for the reason that their number is at a minimum during the breeding season. If, however, interstitial tissue is responsible for sex characters and activity, the present work would indicate that it is the volume of tissue, and not the number of cells, that is important.