In the present work we confirm that gestational malnutrition effects body and brain composition and results in an activation of the synthesis of the brain neurotransmitter 5-hydroxytryptamine. These results also demonstrate more activity of the rate-limiting enzyme tryptophan hydroxylase in the malnourished fetal and postnatal brain. However, the activity of this enzyme remains increased in the brain of nutritionally recovered animals accompanied by an increase in the synthesis of 5-hydroxytryptamine. We therefore suggest that, in the nutritionally recovered animal, the mechanism of activation of this biosynthetic path in the brain may be not dependent on the increased availability of free L-tryptophan observed in malnourished animals, but might be due to a specific change in the enzyme complex itself. This hypothesis is supported by the fact that plasma free and brain L-tryptophan return to normal in the recovered animal.

Decondensation of mammalian epididymal spermatozoa nuclei has been induced by exposure of intact spermatozoa to heparin, including those species in which ejaculated sperm were not susceptible to this treatment. This process occurred in the absence of any disulfide bond cleaving reactant. Swelling of caput epididymal spermatozoa nuclei commenced about 30 min after the addition of heparin, reaching 88% in rat, 33% in rabbit, 26% in pig, and 62% in bull of swelled nuclei after 6 hr of incubation at 37 degrees C with 5000 USP of heparin per ml. Corpus epididymal spermatozoa nuclei of rat and rabbit underwent decondensation at 50 degrees C reaching 24% and 22% of swelled nuclei, respectively, after 6 hr of incubation. The nuclei of the sperm cells of pig and bull from this epididymal region remained highly condensed as well as the nuclei of the cauda epididymal spermatozoa of all the species assayed. Electron microscope observations of the caput epididymal spermatozoa nuclei treated with heparin revealed that the chromatin is organized into nuclear bodies joined by a network of cross-linked and branched chromatin fibers in the species studied.

In the present work we confirm that gestational malnutrition effects body and brain composition and results in an activation of the synthesis of the brain neurotransmitter 5-hydroxytryptamine. These results also demonstrate more activity of the rate-limiting enzyme tryptophan hydroxylase in the malnourished fetal and postnatal brain. However, the activity of this enzyme remains increased in the brain of nutritionally recovered animals accompanied by an increase in the synthesis of 5-hydroxytryptamine. We therefore suggest that, in the nutritionally recovered animal, the mechanism of activation of this biosynthetic path in the brain may be not dependent on the increased availability of free L-tryptophan observed in malnourished animals, but might be due to a specific change in the enzyme complex itself. This hypothesis is supported by the fact that plasma free and brain L-tryptophan return to normal in the recovered animal.

The addition of heparin to human sperm zinc-depleted nuclei releases DNA template restrictions. Spermatozoa depleted of zinc were assayed for ('H-methyl), thymidine incorporation was observed (27,500 t 1,248 dpm of 'H methyl-thymidine). Sperm cells incubated in the presence of 10 mg/ml of soybean trypsin inhibitor shows no effect in sperm nuclear swelling or in the release of DNA template restrictions. This process runs in a parallel fashion to the nuclear swelling induced by heparin, suggesting that swollen nuclei might be the source of DNA template. This was confirmed by autoradiographic studies, since all the sperm cells whose nuclei were judged swollen by morphological criteria also appeared labeled. The fact that there was no need for ATP generating system or of exogenous DNA polymerase emphasized the control role that zinc plays in the physiology of the human spermatozoa.

Swelling sperm nuclei were assayed, exposing them to the combine action of heparin in increasing amounts of seminal plasma 0.1-1.0 ml (124 ? 21 pg of Zn++/ml). An inhibition of almost 30% in the swollen spermatozoa nuclei was observed with 0. I ml of seminal plasma (12 pg of Zn++/ml) reaching to 71% with 74-124 pg of Zn++/ml. Inactivated seminal plasma (boiling) induced the same percentage of inhibition (73%) than normal seminal plasma. Dialyzed seminal plasma (31 pg of Zn+ 'iml) produced an inhibition of 88% of swollen spermatozoa nuclei, the same percentage produced with 30-3s fig of zinc ions (ZnC12). Previous release of sperm zinc by preincubation with EDTA 6 mM changed the decondensation kinetics, making sperm nuclei more susceptible to the action of the glycosamineglycan. No effect was observed in the presence of calcium ions. Therefore, zinc, among its several physiological roles. may act as a nuclear chromatin stabilizer.