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Mehmet Uzumcu, Peter E Kuhn, Jason E Marano, AnnMarie E Armenti and Lisa Passantino

histology, follicle counting, and AMH immunohistochemistry (IHC) while the other was used for western blot analysis. Ovarian histology Ovaries were fixed in Bouin’s fixative for 2 h at room temperature and stored in 70

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C. J. WARD and N. D. DE PROSPO

Kahn & Baker (1964) and Kahn, Baker & Zanotti (1965) have shown that norethynodrel induces mammary gland proliferation in rats comparable to that in pregnancy. The major ovarian effect appears to be reduction in weight (Saunders & Drill, 1958; Lakshman & Nelson, 1963), while observations on ovarian histology are less consistent (Holmes & Mandl, 1962; Baker, Kahn & Besemer, 1965). Baker, Kahn, Zanotti & Headings (1966) have recently found adrenocortical hypertrophy as a response to norethynodrel, but other investigators have reported variable effects on adrenal weight (Holmes & Mandl, 1962; Edgren, Hambourger & Calhoun, 1959). Some studies of the effects of this steroid on hypophysial weight and histology showed no alterations (Lakshman & Nelson, 1963; Saunders, 1964), although Holmes & Mandl (1962) observed an increased weight with depletion of basophils and an increase in chromophobes. Since changes in thyroid function can influence other endocrine factors, the effects of norethynodrel in

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A. CHADWICK and B. J. JORDAN

SUMMARY

The histological appearance, the lipid content and composition of the epithelium of the pigeon crop were investigated after intradermal injection of extracts containing prolactin from representatives of several vertebrate classes. Lipids from crop 'milk' and body depot fat were also studied. There was significantly more lipid in stimulated crop tissue than in the unstimulated crop but significantly less than in crop 'milk', which had approximately half the concentration present in depot fat. Although the lipid staining of histological sections of crops of pigeons injected with prolactin from different vertebrate classes differed strikingly, no difference in lipid concentration in the crop tissue was detected. Equally there were no striking differences between the fatty acid compositions of the triglycerides extracted from the different crops or between these and the triglycerides of crop 'milk' or depot fat. The implications of these findings regarding the effects of prolactin in the pigeon and possible attributes of prolactin from different vertebrate classes are discussed.

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K. MELISSINOS, D. G. PAPADIMITRIOU, ST. K. BARTSOKAS, Z. KATAPOTI and J. HADJIMINAS

Information about the action of vasopressin on the structure of the rat kidney is relatively meagre. Byrom (1939) has described the histological lesions in the rat kidney induced by enormous amounts of Pitressin as 'direct infarction or ischaemic degenerative changes short of infarction of specialized parenchyma...', but emphasized that 'after smaller doses (5–20 units) no definite lesions are seen unless injections are repeated daily or twice daily for at least 3 days'. The lesions were attributed to vascular spasm. However, from experiments on the effect of small doses of Pitressin on the renal circulation of hamsters (Thurau, Deetjen & Kramer, 1960) and rats (Fourman & Kennedy, 1966) it has been suggested that renal blood flow is affected, possibly because of vascular constriction.

The present study was designed to determine the dose of Pitressin which induces histological lesions of the rat kidney. Albino (Wistar) rats of both sexes, weighing 180–240 g,

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J. N. BALL and D. M. ENSOR

The pituitary of the cyprinodont fish Poecilia secretes a hormone that is essential for tolerance of freshwater. Intact fish are euryhaline, but when hypophysectomized cannot tolerate fresh water, though living indefinitely in sea water or dilute sea water. In a typical experiment, ten hypophysectomized P. latipinna, transferred from dilute sea water (12 parts/1000) to fresh water at 25°, displayed severe distress symptoms within 8–46 hr. (mean, 22 hr.). When distressed in fresh water, hypophysectomized fish die in a few hours, but recover if returned immediately to dilute sea water (Ball, unpublished).

The pituitary factor essential for freshwater life is probably not a neurohypophysial hormone, since it is secreted by ectopic pituitary transplants in P. formosa (Ball, Olivereau, Slicher & Kallman, 1965), in which the neurohypophysis is involuted and virtually devoid of histologically detectable neurosecretion (Olivereau & Ball, unpublished observations). Histological studies of the adenohypophysis of P. latipinna and of the

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B. HALÁSZ, L. PUPP and S. UHLARIK

SUMMARY

Anterior pituitary tissue was implanted into the hypothalamus, other parts of the brain and beneath the renal capsule of rats. Grafts in the ventral hypothalamus could retain a normal histological appearance despite a lack of any contact with the capillary loop system of the median eminence.

By observing the location of basophils in the grafts a 'hypophysiotrophic' area has been defined. In other sites the histological structure of the grafts was not maintained.

In animals with grafts in the hypophysiotrophic area the target organs might be well preserved, though sometimes the gonads were preserved and other target organs atrophied. Grafts in other sites always led to atrophy of the target organs.

It is concluded that the material from the hypothalamus essential for the maintenance of anterior pituitary structure and function is not simply a synaptic mediator discharged by nerve terminals into the portal circulation, but a true neurosecretory substance produced by and available from small neurones in the hypothalamus.

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A. D. T. GOVAN

SUMMARY

A histological and histochemical study has been made of ovaries obtained from patients in early pregnancy, the duration of pregnancy varying from 6 to 20 weeks. During the first 10 weeks of pregnancy ovarian structure is virtually unchanged, compared with the post-ovulatory state. From 10 weeks onwards new Graafian follicles appear. These are limited in size, most achieving a maximum diameter of 4 mm. They are characterized by an early and excessive thecal development. Atresia overtakes these follicles and this occurs at all stages of development, suggesting a sudden and possibly recurrent change in gonadotrophic stimulation. Despite atresia the theca persists but histochemical tests suggest that its functional activity is limited. This loss of activity is associated with a recognizable histological change in the thecal cell. It is suggested that most of the alterations in ovarian structure are due to changes in the quality and quantity of gonadotrophins produced at this period of pregnancy.

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ANITA M. MANDL

SUMMARY

Oestrous cycles, as judged by vaginal smears, persist for a variable time after X-ray sterilization of the ovaries, but their phases do not synchronize with the growth and rupture of surviving Graafian follicles and the formation of corpora lutea. Cyclical fluctuations in the size of the uterus and the histological appearance of the vagina occur during but not after the first two oestrous periods following sterilization.

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S. TALANTI and A. EISALO

SUMMARY

The effect of experimental renal hypertension on the hypothalamo-hypophysial neurosecretory system was studied histologically. The amount of neurosecretory material decreased, especially in the neurohypophysis. A marked reduction in the nuclear volume of the neurosecretory ganglion cells occurred, while that of the cells of the other hypothalamic nuclei investigated remained unchanged. The results suggest that the activity of the neurosecretory system is diminished in the experimental conditions used.

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J. P. WHALEN, L. KROOK, I. MACINTYRE and E. A. NUNEZ

SUMMARY

After calcitonin injection, parathyroidectomy, or both, in young growing rats, broadening of the proximal femoral metaphysis with lack of normal concavity of the medial and lateral contours was observed radiographically. Histologically, this abnormal modelling was associated with retarded osteocytic osteolysis. Further manifestations of decelerated resorption included retention and extension of the chondroid core in the secondary spongiosa, retention of cartilage in the cortex and a large increase in the number of cementing lines.