George W. Kittinger

Feto-maternal production and transfer of cortisol in the rhesus (Macaca mulatta>)

Abstract Four pregnant rhesus monkeys cnd their fetuses. were infused constantly with 14 C-cortisol and 3 H-cortisol. Steady state plasma specific activities for 14 C and 3 H-cortisol were obtained after 80 to 90 minutes in both mother and fetus. These data and the rates of infusion of radioactivity were used to calculate the following parameters for both mother and fetus: 1) metabolic clearance rates, 2) production rates, 3) mean adrenal secretory rates, 4) transfer rates from mother to fetus and fetus to mother cnd, 5) the fraction of cortisol in each vascular compartment derived from the maternal and fetal edrenals. Plasma cortisone concentrations, as well as the fraction of cortisone derived from fetal and maternal cortisol were determined. Tetrahydrocortisol and tetrahydrocortisone concentrations were calculated. Mean cortisol secretory rates for the maternal and fetal adrenals were 60.0±11.8 and 1.82±0.42 mg/day. Fifty-eight % of the cortisol in the fetal compartment was of maternal origin. During transfer across the placenta to the fetus, cortisol was largely converted to cortisone. In fetal plasma 76% of the cortisone was of maternal origin. Cortisone concentrations in fetal plasma were higher than those of cortisol.

Quantitative gas chromatography of adrenal cortical steroids.

Abstract A new gas chromatographic method for the simultaneous determination of submicrogram quantities of 17-deoxy- and 17 α-hydroxycorticosteroids is described. Corticosteroid mixtures are treated with periodate in aqueous dioxane to quantitatively convert reactive steroids to etiocholenic acid derivatives. Acidic steroids are removed from a portion of the reaction mixture by extraction with aqueous alkali. The remaining neutral and untreated portions are separately treated with butyric anhydride in pyridine to acylate 3- and 17α-hydroxyl groups. Finally, carboxyl groups in the portion untreated by alkali are esterified with diazomethane. Chromatography of the corticosteroid derivatives on SE-30 and QF-1 gives peak areas that permit calculation of the composition of the original mixture. The validity and precision of the method are supported by data given for analysis of mixtures of known composition.

A new method for determining liver microsomal cholesterol 7α-hydroxylase

A method is described to determine the mass of 7alpha-hydroxy cholesterol synthetized in vitro by liver microsomes without the use of a radioactive substrate.

Quantitative gas chromatography of squirrel monkey (Saimiri sciureus) corticosteroids

Abstract Data are presented documenting the validity and precision of a new computerized gas chromatographic method for quantifying corticosteroids in biologic material. Derivatives suitable for gas chromatographic analysis were obtained in quantitative yield from the initial extracts without preliminary purification by other chromatographic means. Corticosteroids produced by squirrel monkey adrenals were identified and their production rates measured with and without added ACTH. Cortisol (F), cortisone (E), cholesterol (CHOL), and 11β-hydroxyandrostenedione (11BA) were the most abundant steroids produced. In incubations of adrenal slices, F and E together comprised 64% of the total steroid production without added ACTH and 85% with ACTH. The steroid compositions of adrenal vein plasma and incubates of adrenal slices were similar. The identities of F, E, 11BA, and CHOL were confirmed by infrared spectroscopy. Traces of other steroids were present, but their identification was based primarily on gas Chromatographic retention times on SE 30 and QF 1 columns.

In vitro corticosteroidogenesis in primates: A comparative study

Abstract The in vitro production of corticosteroids by adrenal slices from representative species of prosimians, Old World, and New World monkeys has been compared. The increase in blue tetrazolium-positive steroid production in response to ACTH was greatest in slices from New World monkeys and least in slices from prosimians. The F to B ratio, the relative production of cortisol (F) and corticosterone (B), was also highest for the New World monkeys and lowest for the prosimians. These data support the hypothesis that the F to B ratio is genetically determined. It is proposed that this ratio can be maintained within certain limits by each group by the activation or repression of adrenal 17α-hydroxylase.