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A. G. DAVIES

Summary.

Effects of gonadotrophin administration were investigated histologically in the testes of neonatal mice. The hormones used were human pituitary follicle-stimulating hormone (fsh), containing 20% of luteinizing hormone, and human chorionic gonadotrophin (hcg).

fsh treatment increased the numbers of nuclei of spermatogonia and of Sertoli-cell precursors per mouse and caused an even greater increase in the volume of eosinophilic intratubular material. It is thought that the greater part of this material was syncytial cytoplasm of the Sertoli-cell precursors.

Administration of hcg did not have these effects nor modify the effects of fsh treatment.

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A. G. Davies

Summary.

Highly purified preparations of human pituitary gonadotrophins were administered to immature male mice daily for 3 days. The mice were killed on the 9th day after birth and the testes were prepared for electron microscopy. FSH treatment caused an increase in the mass of Sertoli cell cytoplasm, and FSH and LH increased the size of mitochondria in these cells. The number of polysomes in each Sertoli cell was increased after FSH treatment, but the number of ribosomes/polysome was not affected.

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A. G. DAVIES, W. E. DAVIES and CHRISTINE SUMNER

Summary.

Human pituitary FSH was found to increase the incorporation of tritiated lysine into testicular protein in prepubertal mice in vivo. Radioactivity was measured in washed trichloracetic acid precipitates prepared from crude testicular homogenates. The time of maximum response was 8 to 16 hr after subcutaneous injection of the hormone. This was considerably later than the maximum response in vitro reported by other workers.

Neither HCG nor dibutyryl cyclic 3′,5′-adenosine monophosphate had a significant effect on the incorporation of lysine.

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N. R. Lawrence and A. G. Davies

Summary. The effects of FSH, HCG, GH and testosterone on testicular protein synthesis were investigated in hypophysectomized adult mice by measuring the incorporation of tritiated lysine into acid-precipitable material. The incorporation per mg protein was increased by FSH, HCG and GH but decreased by testosterone. The maximum effect of FSH occurred at between 8 and 14 h after administration of the hormone, much later than found in vitro for the rat.

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M. R. Bansal and A. G. Davies

Summary. Administration of 80 or 160 pg testosterone oenanthate s.c. three times per week for 8 or 12 weeks reduced testis weight and increased seminal vesicle weight in mice. Radioimmunoassay indicated that treatment increased serum testosterone concentrations. Treatment with testosterone oenanthate decreased the number of step 16 and step 7 spermatids, pachytene spermatocytes and type A spermatogonia, and particularly reduced the proportion of step 7 spermatids which matured to form step 16 spermatids.

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A. G. Davies, N. R. Lawrence and S. S. Lynch

Summary. In-vivo testicular binding of highly purified pituitary FSH, labelled by a method which did not significantly affect biological potency, was hormone-specific, tissue-specific and dose-dependent. Hypophysectomy of mice was followed by a progressive increase in the amount of 125I-labelled FSH per unit weight of testis but not in the total amount of hormone taken up by the testis. Maximum binding occurred at 4 h in a membrane-containing fraction prepared by high-speed ultracentrifugation of testicular homogenate. This is considerably later than has been reported for testicular tissue incubated in vitro at 37°C.