Gibt es eine intrauterine Nierensekretion?

Changes in the Electrolytes, Urea and Osmolality of the Amniotic Fluid With Advancing Pregnancy*

“…Few measurements of amniotic fluid osmotic characteristics in early pregnancy have been made (Grunbaum, 1905;Guthmann and May, 1930;Makepeace et al, 1931 ;Battaglia ef al., 1959). All suggested osmotic equilibrium with maternal serum.…”

“…A rise in amniotic fluid urea concentration with advancing pregnancy has been reported (Guthmann and May, 1930;Friedberg, 1955;Sozanskii, 1961), and a mean amniotic fluid urea excess over fetal and maternal plasma at term of 12.5 mg. per 100 ml. was found (Sozanskii, 1961 ;Huntingford and Marsden, 1966).…”

The secretion of urine by newborn infants

“…Very little work has been done on the matter, but it has been shown that some functions are in evidence at least as early as the second or third month [Cameron & Chambers, 1938;Hewer, 1924]. Analysis of liquor amnii at serial stages of foetal development has indicated that long before birth some urea and uric acid are being excreted by the kidney [Guthmann & May, 1930]. According to Tausch [1936], who reviewed the literature on foetal kidney function and himself catheterized a great number of infants immediately after delivery, the urine of the last few hours or days of foetal life is generally acid, and has a lower specific gravity than that found in adults.…”

The Concentration of 5-Hydroxyindole Acetic Acid in Foetal Urine in Normal and Toxaemic Pregnancies

“…Potter and O sathanondh [18] suggest on morphological grounds that the secretion of urine starts at the 8th week of gestation. Giithmann and M ay [7] found that urea appeared in the amniotic fluid at 10 weeks and inferred that this was the time when renal function started. We have observed a 14-week foetus passing urine.…”