The conversion of dehydroepiandrosterone-7-alpha-3H to oestrogens by corpora lutea of early human pregnancy

Incubation of two corpora lutea of early human pregnancy in the presence of dehydroepiandrosterone-7α-3H resulted in a 33—44% yield of oestrone plus 17β-oestradiol. The major oestrogen formed in homogenate preparations was oestrone while in a slice preparation it was 17β-oestradiol. Oestrone and 17β-oestradiol were characterized by solvent partition, paper chromatography and crystallization to constant specific activity after addition of carrier. Acetates of the crystallized oestrogens had the same specific activities as the parent steroids and these derivatives were further identified by thin layer chromatography. These results suggest that dehydroepiandrosterone may serve as a major precursor for oestrogen biosynthesis by human corpus luteum of early pregnancy.

Conversion of dehydroepiandrosterone-7-alpha-3H to oestrogens by corpus luteum, placenta, and placenta plus foetal viscera in early human pregnancy

A corpus luteum, placenta, and placenta plus foetal viscera of a 13-week old human pregnancy were incubated with dehydroepiandrosterone-7α-3H in vitro. Conversion to oestrone and 17β-oestradiol was found in all incubates. Oestriol was formed from dehydroepiandrosterone only in the incubate of placenta plus foetal viscera. Thus, in early pregnancy dehydroepiandrosterone may serve as a precursor for oestrogen biosynthesis not only in the foeto-placental compartment, but also in the corpus luteum.

Effect of glucagon on the metabolism of lipids and on urea formation by the perfused rat liver

Livers obtained from fed or fasted rats were perfused with blood from fasted rats with and without the addition of glucagon and/or a hyperlipemic serum (HLS).

In addition to its well-known hyperglycemic effect, glucagon increased the blood levels of the ketone bodies and of urea, and decreased the levels of cholesterol, total lipids and NEFA.

The magnitude of the effects noted were dependent upon the previous state of the liver and the addition of the hyperlipemic serum.

In the fed liver, glucagon produced a greater degree of hyperglycemia than in the fasted liver and this effect was enhanced by the addition of a hyperlipemic serum. In fasted livers the addition of a hyperlipemic serum did not increase the hyperglycemia produced by glucagon alone.

Total lipids, cholesterol and NEFA were decreased when glucagon was added to either the fasted or fed liver, in the presence or absence of a hyperlipemic serum. Glucagon caused a greater increase in the level of ketone bodies in the fasted than in the fed liver and this effect was increased by the addition of a serum rich in lipids.

The addition of glucagon caused an increase in the levels of urea and this effect was reduced when a hyperlipemic scrum was acMted.