摘要:

AbstractEarly development of the bat,Glossophaga soricina, was investigated histologically using 71 pregnant animals removed from a laboratory colony at timed intervals after mating.Implantation was initiated between days 12 and 14 post‐coitum, i.e., shortly after entrance of the blastocyst into the simplex uterus. The site of implantation was a narrow, tubular segment, the intramural uterine cornu, interposed between the end of the oviduct and the main uterine cavity. The intramural uterine cornu is probably homologous to the cranial end of a horn in a bicornuate uterus. Attachment of the blastocyst was central and circumferential, and orientation of the inner cell mass was cephalad in line with the long axis of the cornu. Implantation was secondarily interstitial in the fundal endometrium, as the lumen of the intramural uterine cornu was obliterated and the decidua filled in around the expanding blastocyst.The yolk sac was formed between days 15 and 24 by the expansion and coalescence of pockets within a meshwork of endoderm. Endoderm completely surrounded the inner cell mass until the onset of amniogenesis and served to suspend the inner cell mass from the cytotrophoblast. A decidual reaction first appeared on day 15 after trophoblastic penetration to the endometrial stroma. Syncytiotrophoblast developed as engulfment of maternal capillaries began on day 16, and the capillary endothelium was rapidly disrupted. Amniogenesis occurred by cavitation, beginning on day 26, and shield formation was complete in some animals by day 3

ISSN:0002-9106    

DOI:10.1002/aja.1001390102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1974

数据来源: WILEY

摘要:

AbstractIn hamsters hypophysectomized on day 1 of the cycle (morning of ovulation) on days 1–28 post‐hypophysectomy 99% of follicular development is limited to small and medium sized follicles with no more than five layers of granulosal cells. Since the largest preantral follicles on day 1 of the cycle have 10–12 layers of granulosal cells, it is evident that follicles become dependent on gonadotropins at an early stage of their maturation.The daily injection of 200 μg ovine follicle stimulating hormone (FSH) on days 8–11 post‐hypophysectomy results in large antral follicles; when 10 μg ovine luteinizing hormone (LH) is then injected the animals ovulate 32 eggs. When 200 μg FSH on day 8 post‐hypophysectomy is followed by 50 μg FSH on days 9–11, injecting LH results in the ovulation of nine eggs — comparable to the ovulation rate of intact hamsters. These experiments indicate that superovulation depends on sustained high levels of FSH whereas the ovulation of a normal number of eggs requires an initially high level of FSH and then much lower maintenance levels.When replacement therapy with 200 μg FSH for four days is started on the day of hypophysectomy (day 1) or day 2, follicles fail to develop past the six‐seven granulosal layer stage. However, deferring the initial injection of FSH until day 3 results in antral follicles that are ovulated by LH (ovulation = 36 eggs). This suggests that functional corpora lutea inhibit the effects of FSH on follicular growth. Progesterone administered to hypophysectomized hamsters (days 8–11 post‐hypophysectomy) increases the percentage of medium follicles at the expense of smaller stages. Progesterone injected daily along with FSH also prevents follicular development past the six‐seven granulosal layer stage in 14 of

ISSN:0002-9106    

DOI:10.1002/aja.1001390103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1974

数据来源: WILEY

摘要:

AbstractElectron microscopic studies of hepatocytes from sham‐operated, hypophysectomized, and hypophysectomized rats treated with somatotropin were undertaken in order to obtain morphological information on the mechanism of hormone action at the cellular level. Fed and fasted animals from each of the above groups were studied. Hepatocytes from fed rats of the three groups showed similar characteristics: periportal cells contained large dense masses of glycogen throughout the cytosome with relatively little smooth endoplasmic reticulum; mid‐lobular cells displayed small dense masses of glycogen with few associated elements of smooth endoplasmic reticulum; centrilobular hepatocytes showed dispersed glycogen and abundant smooth endoplasmic reticulum. Hepatocytes from hypophysectomized rats fasted fifteen hours showed significant alterations in structure when compared with liver cells from sham‐operated animals. Differences noted were: decrease in mid‐lobular cell size and amount of smooth endoplasmic reticulum; decrease in glycogen, number of ribosomes and polysomes per hepatocyte; disorganization of the rough endoplasmic reticulum; and swelling of mitochondria and increase in number per cytoplsmic volume. Periportal hepatocytes from fasted hypophysectomized rats treated with somatotropin for ten days contain numerous small masses of glycogen with elements of smooth endoplasmic reticulum at the periphery of the glycogen masses. Mid‐lobular and centrilobular hepatocytes contain masses of dispersed glycogen with an abundance of smooth endoplasmic reticulum associated with the glycogen

ISSN:0002-9106    

DOI:10.1002/aja.1001390104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1974

数据来源: WILEY

摘要:

AbstractParenchymal perfusions of rat pineal glands with India ink solutions reveal an extravascular and intercellular system of continuous microscopic channels containing ink perfusate. This system has two, apparently interconnecting, components: pericapillary sleeves or networks, and intralobular canaliculi 0.2–0.4 μ in diameter and enmeshing the pinealocytes individually.Perfusion of the canaliculi was reduced or inhibited by either partial dehydration or exposure to hypertonic solutions, and was blocked when the perfusate contained either CaCl2or trypsin. Hyaluronidase was without effect. The extent to which the canaliculi could be perfused followed a 24‐hour‐rhythm with a peak (mean maximal canalicular perfusion distance = 95 μ) near the end of the daily environmental light phase, and a trough (mean maximal canalicular perfusion distance = 13 μ) during the dark phase. This rhythm resembles that in rat pineal content of 5‐hydroxytryptamine. Dark‐phase perfusion distances equivalent to those of the light‐phase were obtained when 5‐hydroxytryptamine (5 × 10−3M) was present in the perfusate. In similar circumstances norepinephrine, heparin and melatonin were without effect.It is suggested that this system of canaliculi may be significant for transport activities between pinealocytes and capillaries and that its circadian and local patency may be regulated in part by release of 5‐hydroxytryptamine by the pinealocytes, and in

ISSN:0002-9106    

DOI:10.1002/aja.1001390105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1974

数据来源: WILEY

摘要:

AbstractFine structural observations on the corpus luteum of late pregnancy in rhesus monkeys (Macaca mulatta) are described. Ovariectomy was performed between 141 and 146 days of pregnancy. Granulosa lutein cells measured 25 to 30 μ and were supplied by fenestrated capillaries. The plasma membranes of neighboring cells formed intercellular canaliculi which were bordered by microvilli. The nuclei were large and contained a nucleolus and peripheral heterochromatin. The central region of the cytoplasm contained a high concentration of: (1) rod‐shaped mitochondria with tubular cristae and some electron‐opaque inclusions in their matrices, (2) elaborate Golgi complexes and associated large tubular cisternae, and (3) tubular as well as cisternal agranular endoplasmic reticulum. The more peripheral region of the cytoplasm was filled with: (1) well developed parallel arrays of granular endoplasmic reticulum, (2) bundles of 50 Å filaments with dense areas, and (3) dispersed lipid droplets. Membrane‐bound granules of various types were observed in most cells. Large lacunae were present in the cytoplasm which were not confluent with the intercellular canaliculi or the perivascular spaces. Microvilli projected into the empty‐appearing lumen of the lacunae. It was concluded that the morphological features of the granulosa lutein cells of late pregnancy were consistent with those considered to be necessary for steroidogenic

ISSN:0002-9106    

DOI:10.1002/aja.1001390106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1974

数据来源: WILEY

摘要:

AbstractThe purpose of this study was to ascertain the effects of different amounts of progesterone on estrogen‐induced DNA synthesis in the vaginal and lower cervical epithelia of the rat. Ovariectomized rats were injected subcutaneously with 1 μg of estradiol‐17β dipropionate or with estradiol and 1, 5, 10 or 15 mg of progesterone for three days; control rats received oil. Tritiated thymidine was injected one hour prior to necropsy; the tissues were processed for autoradiographic study and the percentages of labeled nuclei in the basal layer from the lower half of both the vagina and cervix were determined. In the group of rats given estradiol and 1 mg of progesterone the thymidine uptake in the vagina was significantly increased over that of rats given only estrogen. However, in the rats treated with estradiol and 5, 10 or 15 mg of progesterone, the extent of DNA replication in the basal epithelial nuclei was similar to the estrogen group. These responses were compared with those of the basal epithelium from the lower half of the cervix. None of the estrogen‐progesterone treatments increased the thymidine index in the cervical epithelium above that of estrogen alone; additionally, 5, 10 or 15 mg of progesterone given with estrogen suppressed DNA replication. These data indicate that stratified epithelia of these two portions of the reproductive tract respond differently to exogenous ovarian h

ISSN:0002-9106    

DOI:10.1002/aja.1001390107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1974

数据来源: WILEY

摘要:

AbstractUtilizing immunohistochemistry with rabbit antiserum to synthetic luteinizing hormone‐releasing hormone (LRH), LRH was localized in the peripheral region of the median eminence in the mouse and rat, and more generally in the median eminence of the guinea pi

ISSN:0002-9106    

DOI:10.1002/aja.1001390108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1974

数据来源: WILEY

摘要:

AbstractParacrystalline aggregates of microtubules were observed by electron microscopy in some cells of the anterior pituitary glands from ten untreated chinchillas (Chinchilla laniger). Longitudinal section of the paracrystals revealed regular arrays of electron‐opaque lines parallel to the long axis of the microtubules and in transverse sections the paracrystals showed an unusual checkerboard pattern of closely packed microtubules. However, the inner wall of each subunit was hexagonal in shap

ISSN:0002-9106    

DOI:10.1002/aja.1001390109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1974

数据来源: WILEY

摘要:

AbstractRetrograde transport in peripheral nerve was investigated by injecting3H‐leucine unilaterally into tongues of adult rats. The animals were killed at varied intervals up to 14 days following injection, and autoradiographs were prepared. Labeled material was observed in intrinsic nerves of the tongues in all animals studied. The somata of hypoglossal neurons, however, were not labeled, indicating that radioactive material had not been transported throughout the length of the nerve cell

ISSN:0002-9106    

DOI:10.1002/aja.1001390110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1974

数据来源: WILEY

摘要:

AbstractIn spindles of rat muscles, the particular class of intrafusal fiber that is unreactive over its entire striated length when incubated for alkali‐stable “myofibrillar” ATPase, exhibits pronounced regional differences in staining following incubation for acid‐stable ATPase. This variation along the contractile polar regions of the fiber can easily lead to misinterpretations of intrafusal fiber type, as well as the erroneous suggestion of two distinct populations of muscle spindles. Furthermore, such regional staining differences are strongly suggestive of variations in the contractile apparatus along certain intrafusal muscle

ISSN:0002-9106    

DOI:10.1002/aja.1001390111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1974

数据来源: WILEY