Somatoliberin stimulates secretion of growth hormone and has no effect on secretion of prolactin in primary cultures of hypophyseal adenoma cells obtained from acromegalic patients. A short-term contact of the cells with somatostatin inhibits secretion of growth hormone, while a long-term contact with this hormone inhibits prolactin production. Somatoliberin abolishes the inhibitory effect of somatostatin on the growth hormone secretion and at high concentrations stimulates it.

Antibodies to adeno-pituitary cell surface antigen (PCSA) were studied in 40 untreated children with idiopathic growth hormone (GH) deficiency to elucidate the role of autoimmune disorders in the pathogenesis of GH deficiency. Antibodies to rat PCSA were assayed by ELISA. PCSA was detected in 15% of patients with GH deficiency, in contrast to that in healthy children and children with autoimmune thyroid diseases. The authors consider that in some cases GH deficiency may be caused by autoimmune hypophysitis. A family study revealed PCSA in 25% of mothers of patients with GH deficiency. In a population of healthy women PCSA was detected in 5.7% cases. Hence, a hereditary background of autoimmune abnormality cannot be completely ruled out.

Some features of the morphological cellular structure of prolactin secreting human pituitary adenomas and their secretion of prolactin and somatotropic hormone in primary suspension cultures were investigated. A possiblein vitro proliferation of lactotrophs was established. The inhibitory effect of somatostatin and its synthetic analog sandostatin, on prolactin secretion in prolactinomas was found to be less than in somatotropic hormone-secreting pituitary tumors.

The effect of monomeric (glycosylated and unglycosylated) and dimeric form of porcine prolactin on change of the blood levels of triglycerides (TG) and cholesterol in lipoproteins (LP) of different density and the activity of the main enzymes of plasmatic and liver lipid metabolism were studied under the conditions of experimental hyperprolactinemia in rabbits. It was shown to be accompanied by dyslipoproteinemia, characterized by a stable rise of TG in LP of very low, high and low density as well as by a rise of cholesterol concentration in VLDL and its decrease in HDL. Such changes in LP showed correlation with lowered activity of lipoprotein lipase, triglyceride lipase of the liver and plasmatic postheparin lipolytic activity. Analysis of prolactin-induced dyslipoproteinemia has shown that changes in plasma lipoproteins are of atherogenic nature.

A comparative analysis of immunological properties of previously isolated and structurally characterized glycosylated porcine prolactin was performed. Immunoelectrophoresis with antisera to nonmodified and glycolysated hormones revealed no qualitative differences in their immunological properties. Two radioimmunoassay systems for glycosylated and nonglycosylated prolactin were developed on the basis of these antisera. Glycosylated prolactin in both systems was shown to possess decreased immunoreactivity making up 40-50% of nonmodified prolactin activity.

The corticotropins from two species of whales, e. g. seiwhale (Balaenoptera borealis) and finwhale (Balaenoptera physalus) were subjected to hydrolysis by trypsin, chymotrypsin and pepsin. The peptide fragments were separated by gel-filtration through Sephadex and partition paper chromatography. The study of the amino acid sequence of the peptides obtained allowed to establish the primary structure of corticotropin from both species, which was found structurally identical to human corticotropin.