ABSTRACT
Under certain conditions the i.p. injection of L-tryptophan leads to a reduction of elimination of Na+. At the same time, the fractional Na+ -reabsorption increases. No increase in the absolute tubular sodium transport rate was observed since the significantly reduced plasma-sodium concentration leads to a decreased sodium load. The most probable cause of a decreased plasma-sodium concentration seems to be a retention of sodium-free water under the chosen conditions of infusion. The water retention is compatible with the antidiuretic effect of 5-hydroxytryptamine.
Subject(s)
Diuresis/drug effects , Sodium/metabolism , Tryptophan/pharmacology , Animals , Glomerular Filtration Rate , Male , Osmolar Concentration , Phenylalanine/pharmacology , Rats , Sodium/blood , Stereoisomerism , Time Factors , Tryptophan/analogs & derivatives , Water-Electrolyte Balance/drug effectsABSTRACT
Gilts that had already reached sexual maturity at the time of insemination showed a higher rate of oestrus and better litter size than immature animals. Therefore animals selected for breeding should have had at least one oestrous cycle. Onset of puberty can be judged by the occurence of a first oestrous with pronounced redness and swelling of the vulva, but without willingness to be mounted. Changing the housing or exercising the gilts, rendered necessary by the production process, had a stimulating effect on the onset of puberal oestrus. Age at onset of sexual maturity did not affect the performance of gilts in their first production cycle, but litter size was greater when the rate of weigth gain was high.
