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Biomedical subjects

A G Frantz

Publications and source records attributed to A G Frantz.

102 records · Page 6Linked to original sources
PubMed1971

Human prolactin: measurement in plasma by in vitro bioassay.

Prolactin has been measured in unextracted human plasma by a sensitive and specific in vitro bioassay. Secretory activity of breast tissue fragments from mid-pregnant mice, incubated in organ culture with human plasma, serves as the histologic end point. Sensitivity is 5 ng/ml (0.14 mU/ml) or somewhat better for ovine prolactin, and approximately 0.42 mU/ml for prolactin activity of human plasma at the dilutions used in the assay. Human growth hormone as it circulates in blood, like the material extracted from pituitary glands, is strongly lactogenic. Antisera to human growth hormone are capable of completely neutralizing the prolactin effect of large amounts (600 ng/ml) of human growth hormone added to the system. Plasma prolactin activity is less than 0.42 mU/ml in normal men and women. Of 26 patients with nonpuerperal galactorrhea, 14 had elevated prolactin activities ranging from 0.42 to 3.5 mU/ml. Growth hormone levels by radioimmunoassay were far too low, in general, to account for the observed prolactin activity. All of 14 nursing mothers, 1-30 days post partum, had elevated prolactin activity with a mean of 2.29 and a total range of 0.56-4.5 mU/ml. Growth hormone was in the low normal range in all of these subjects. Seven patients on psychoactive drugs of the phenothiazine series similarly had elevated prolactin activity with low growth hormone. Antiserum to human growth hormone, when preincubated with plasma samples from each of these three groups of subjects, produced no significant inhibition of prolactin activity. In two acromegalic patients with markedly elevated growth hormone levels, antiserum to growth hormone produced complete inhibition of prolactin activity in one and partial inhibition in the other. These studies indicate that human growth hormone and human prolactin are separate molecules, with little if any immunologic cross-reactivity, at least as demonstrated by the antisera used in this study, and that their release is governed by different physiologic mechanisms.

Acromegaly↗
PubMed1970

Prolactin: evidence that it is separate from growth hormone in human blood.

A highly sensitive bioassay has been developed for prolactin, which uses a mammalian end organ and which is capable of measuring the hormone in unextracted human plasma. High prolactin activity, largely neutralizable with antiserum to human growth hormone, is stimulated along with high immunoassayable growth hormone by insulin-induced hypoglycemia. High prolactin activity, not neutralizable with antiserum to growth hormone, exists with low concentrations of plasma growth hormone in postpartum patients and patients with galactorrhea.

Acromegaly↗