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Biomedical subjects

J Sandow

Publications and source records attributed to J Sandow.

At least 91 records · Page 5Linked to original sources
PubMed1978

Chronic treatment with LH-RH in golden hamsters.

Male golden hamsters were treated with low doses (50 or 100 ng) or high doses (500-1000 ng) of LH-RH for periods of 10 to 21 days. Gonadal atrophy was induced by blinding. Treatment of intact hamsters with high doses of LH-RH reduced pituitary sensitivity to a test dose of LH-RH given at the end of the experiment. Concomitantly, testis and seminal vesicles were reduced in weight. In blind hamsters with gonadal atrophy, low dose treatment with LH-RH for 21 days reversed testicular atrophy and restored spermatogenesis, while the high dose treatment partly reversed testicular atrophy (viz. increased tubular diameter) but inhibited spermatogenesis. Low dose treatment also increased testicular and seminal vesicles weight in blinded hamsters, whereas high dose treatment did not change these parameters. It is concluded, that a positive effect on testicular functiion may only be obtained by low dose treatment with LH-RH, whereas high dose treatment induces a negative feedback blocking the effect of LH-RH on pituitary gonadotrophin secretion.

Animals↗
PubMed1977

Synthesis and properties of [11-serine]alpha-melanotropin.

[Ser11]alpha-melanotropin has been prepared and its melanotropic activity compared with that of alpha-melanotropin and several known analogues. Full activity does not depend on the positive charge of 11-lysine in alpha-melanotropin but on the hydrophilic character of the amino group or a corresponding residue. A shift, or even more, a loss of such a group decreases the melanotropic activity.

Amino Acid Sequence↗
PubMed1977

Gonadotrophin release by a highly active analogue of luteinizing hormone releasing hormone in rats immunized against luteinizing hormone releasing hormone.

Immunization against luteinizing hormone releasing hormone (LH-RH) in adult male rats produced a progressive decline in LH and FSH in the circulation to low or non-detectable levels. D-Serine-tertiary-butyl6,des-glycine-NH210 LH-RH ethylamide is an analogue of LH-RH having highly active LH-RH properties in the normal rat. Because it is also immunologically different from LH-RH it can stimulate gonadotrophin release from the anterior pituitary gland of rats immunized against LH-RH without interference from the antibody. The analogue stimulated LH and FSH release in rats 15 weeks after immunization against LH-RH when antibody titre was highest, and after long-term (35 weeks) immunization against LH-RH. D-Serine-tertiary-butyl6,des-glycine-NH210 LH-RH ethylamide and related analogues are therefore potentially useful for reversing the effects of immunization against LH-RH.

Animals↗
PubMed1975

Purification and characterisation of two porcine hypothalamic fractions with LH-releasing activity: evidence for a single LH and FSH-releasing hormone.

Two fractions with LH releasing activity were obtained from porcine hypothalami by Enzmann et al. (1972). These fractions were designated E 57 and E 203. By comparison with pure natural LH-RH and synthetic LH-RH, E 203 was identified as purified natural LH-RH. E 57, which has only 25% of the activity of E 203, was further evaluated for its biological and immunological activity. E 57 has the same ratio of LH/FSH-releasing activity as natural LH-RH. The binding to a specific LH-RH antiserum is identical with that of natural LH-RH and E 203. It is concluded, that E 57 is an artifact of isolation derived from natural LH-RH. These findings can be considered as additional evidence for the identity of the hypothalamic LH and FSH releasing hormone, since both gonadotrophins are stimulated by the two hypothalamic fractions.

Animals↗