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Absorption of organic anions (phenol red, bromphenol blue and bromosulphonphthalein) has been studied after their application to rat liver surface in-vivo, employing a cylindrical glass cell (i.d. 9 mm, area 0.64 cm2). Every drug appeared gradually in the blood with the peak level at about 1 h, after which its concentration declined slowly. Absorbed model drug was efficiently excreted into the bile. These observations appear to indicate the possibility of drug absorption from liver surface membrane. Absorption ratios of model drugs were estimated to be more than 59 % in 6 h. As to phenol red, its biliary recovery and metabolism ratio did not change as compared with that of i.v. administration.
The Chemical Forms in Which Phenol Red is Secreted into the Bile Of Rats
Summary Rats with ligated renal pedicles and a cannulated bile duct received an intravenous injection of phenol red. Paper chromatography of the bile revealed the presence of two colored substances, one of which was chromatographically identical with phenol red. The other substance could be converted to phenol red by acid hydrolysis and was thus a conjugated form of the dye. The conjugate appeared to be a glucuronide, since it was completely converted to phenol red on treatment with beta-glucuronidase. Within 2 hours after the injection of phenol red, 55% of the dose was excreted in bile as the unchanged compound, and 27% as the glucuronide conjugate. The conjugate, like the parent compound, appeared to be actively secreted into bile.
Testosterone levels, handedness and sex ratio at birth.
Geschwind has hypothesized that levels of androgens in utero affect postnatal laterality preferences, high levels being associated with left-handedness of offspring. I have hypothesized that high parental androgen levels at the time of conception are associated with subsequent male births. However, left-handed parents seem to produce an excess of female, not male, offspring. This finding could be reconciled with the two hypotheses if individuals who were exposed to high levels of androgens in utero had low circulating levels in adulthood. Some evidence for this loophole is reviewed here. Lyster & Lloyd (1987, J. theor. Biol. 126, 125) have reported that (consistent with the hypotheses) index left-handed men have an excess of brothers; but, contrary to the hypotheses, index left-handed women have an excess of sisters. Accordingly these authors proposed that left-handedness in females is associated not with high levels of androgen in utero, but with a "sensitivity" to it. If such sensitivity were associated with low androgen levels, it might explain an excess of sisters among the sibs of left-handed women. It is shown here that evidence in agreement with this hypothesis (though not discriminating between it and Geschwind's) suggests that the sex ratios of offspring of LH male x RH female and of RH male x LH female matings, are both low.