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Zvi Laron

ABSTRACT

The effect of fluoxymesterone (Halotestin) on body weight and body height has been studied in 13 children with growth retardation and underweight.

It was found that fluoxymesterone administered for periods of 3 months in a dose of 0.1 to 0.15 mg per kg body weight per day had a beneficial effect on body weight and linear growth rate. A daily dose greater than 0.25 mg/kg body weight had virilizing effects.

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Zvi Laron and Sara Assa

ABSTRACT

Human growth hormone (HGH) prepared from human pituitary glands by the method of Raben (1959) showed two components on agar gel electrophoresis. Fraction I corresponded to a slow alpha-globulin, and fraction II had a mobility between alpha and beta-globulin. On agar gel immunoelectrophoresis using HGH and rabbit antiserum to HGH, these two components showed immunological identity. By using agar gel immunoelectrophoresis and the haemagglutination technique HGH preparations of both Raben and Li type were shown to be contaminated with human albumin. Antiserum to human growth hormone containing also antibodies against human albumin was purified by adsorption with human albumin. It is postulated that part of the difficulties encountered in the use of the haemagglutination-inhibition technique to determine growth hormone concentration in serum, is due to impurities in the human growth hormone preparations and antisera to these preparations in use.

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Zvi Dickerman, Ruth Prager-Lewin and Zvi Laron

ABSTRACT

A standard LH-RH test (50 μg/m2) given iv was carried out in 65 normal girls, 42 of them pre-pubertal aged from 47/12 to 11 years and 23 in the early stage of puberty, aged from 9 to 129/12 years.

The results indicate that in pre-pubertal girls the basal levels of the plasma gonadotrophins remain steady (LH 0.6 ± 0.1 mIU/ml; FSH 0.8 ± 0.1 mIU/ml, m ± sd) and that there is a small but significant response of LH to LH-RH (1.6 ± 0.2 mIU/ml). During this period the FSH response to LH-RH is very marked (8.0 ± 1.0 mIU/ml) with a gradual, significant decrease seen towards the onset of puberty (6.5 ± 0.9 mIU/ml, P < 0.001). These results support earlier reports that the LH-RH test is a useful tool to evaluate the secretion of pituitary LH and FSH in early childhood.

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Zvi Laron and Avivah Kowadlo-Silbergeld

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Zvi Laron and Avivah Kowadlo-Silbergeld

ABSTRACT

Groups of starved female rats were treated with either testosterone propionate, 19-norandrostenolone phenylpropionate (Nandrolone, Durabolin) or bovine growth hormone (BGH). The effect of these hormones on the concentration of the plasma unesterified fatty acids (UFA) was then studied in blood withdrawn from the heart daily. As controls groups of rats were treated with either oil or saline, i. e. the vehicles for the above named hormones. It was found that both testosterone and Nandrolone caused a marked increase in plasma UFA concentrations, similar to the effects obtained by growth hormone.

Accepting UFA as an index of the metabolic activity of adipose tissue, it is concluded that testosterone and its less androgenic derivative Nandrolone possess fat mobilizing properties. In view of the fact that during puberty in boys the subcutaneous fat tissue decreases as compared with girls and that eunuchs have a tendency to obesity, it is suggested that androgens play an active physiological role in adipose tissue metabolism.

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Zvi Laron and Avivah Kowadlo-Silbergeld

ABSTRACT

Groups of starved rats of both sexes were treated with three daily injections of either oestradiol benzoate (OB) alone or in combination with testosterone propionate (TP). The effect of these hormones on the concentration of the plasma unesterified fatty acids (UFA) was studied by withdrawing blood daily from the heart. For control conditions, groups of rats were treated with either olive oil, the vehicle of the above hormones, or no injection at all. It was found that oestradiol benzoate, 5 mg per dose, caused a mean rise of plasma UFA up to 1376 ± 209 μeq/litre; 10 mg OB per dose elevated the mean plasma UFA concentration to 3492 ± 246 μeq/litre; and a combination of 5 mg OB + 10 mg TP per dose resulted in a mean plasma UFA concentration of 2379 ± 236 μeq/litre.

It is concluded that oestrogens possess a fat mobilising property similar to and possibly stronger than that of androgens.

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Avivah Silbergeld, Rivka Mamet, Zvi Laron and Zvi Nevo

Abstract.

Embryonic chick pelvic cartilages were incubated in the presence of insulin like growth factor (IGF) (1–100 μU/ml), as well as normal human serum (5%), with radiolabelled precursors of proteoglycan (PG) synthesis: L-[3-3H]serine, D-[6-3H]glucosamine and [35S]Na2SO4. IGF alone (1–15 μU/ml), stimulated in a dose-dependent manner D-[6-3H]glucosamine incorporation into tissue-bound and soluble isolated glycosaminoglycan (GAG) chains. L-[3-3H]serine incorporation into PG molecules was not stimulated by IGF (1–100 μU/ml), despite the increase in the uptake of this precursor into intact cartilage. [35S]Na2SO4 incorporation was unaffected by IGF. Serum promoted the uptake of all three precursors into tissue-bound glycosaminoglycans. It was postulated that IGF could stimulate proteoglycan synthesis not only by elongating existing chondroitin sulphate chains but also by increased synthesis of other sugar chains e.g. keratan sulphate and oligosaccharides.