Hiroyasu Okahata

Effect of Zinc Ion on Human Chorionic Gonadotropin-Stimulated in Vitro Production of Cyclic AMP and Testosterone by Rat Testis

Summary: This study explores the effects of several divalent metal ions on the in vitro production of cyclic AMP, cyclic GMP, and testosterone by rat testicular tissue and on the amount of binding of [125I]human chorionic gonadotropin (hCG) in the testis. Zn2+ at concentrations of 10-6 to 10-4 M enhanced the hCG-stimulated production of cyclic AMP and testosterone, but only in the presence of Ca2+. [125I]hCG binding to rat testicular tissue was not affected by Zn2+. Cu2+, Ni2+, Co2+, and Mn2+ did not increase cyclic AMP or testosterone production in concentrations of 10-7 to 10-3 M and even inhibited them at a high concentration (10-2 M). Cyclic GMP production was not affected by these divalent ions. These results suggest that Zn2+ may play an important role in rat testicular steroidogenesis.

Gastrin/cholecystokinin-like immunoreactivity in human blood cells

In the gastrin and/or cholecystokinin-like immunoreactivity (G/CCK-LI) elution patterns of blood cells in human adults, erythrocyte (RBC) elution pattern has three peaks which are coeluted with gastrin-34 (G34), gastrin-17 (G17) and Vt, and polymorphonuclear leukocyte (PMN) and mononuclear cell (MNC) elution patterns have four peaks which are coeluted with Vo, G34, G17 and Vt. The content of G/CCK-LI in RBC is 1.20 +/- 0.54 f mole/10(8) cells (mean +/- SD). That in PMN and MNC is 1.44 +/- 0.67 p mole/10(8) cells and 1.67 +/- 0.76 p mole/10(8) cells, respectively.

Development of antral gastrin-like immunoreactivity and pituitary CCK8/gastrin-like immunoreactivity in rats

Gel filtration of antral extract of adult rats revealed gastrin-17 and gastrin-34. Gel filtration of anterior pituitary extract showed CCK8 and gastrin-17, whereas posterior pituitary extract showed only a CCK8. Antral gastrin-like immunoreactivity (G-LI) increased after milk feeding and especially after weaning was started. Changes in diet may exert a profound influence on the ontogenic development of antral G-LI, but not pituitary CCK8/G-LI.

Neurotensin-like immunoreactivity (NTLI) concentration in the cerebrospinal fluid of children and its alteration in a febrile aseptic meningitis

Neurotensin-like immunoreactivity (NTLI) concentrations in the cerebrospinal fluid (CSF) of normal children and patients with febrile aseptic meningitis, aged 7 months to 15 years, were studied. The NTLI concentrations in CSF of 27 children with normal CSF findings were 160.1 +/- 54.6 pg/ml (mean +/- S.D.). The NTLI concentration in CSF of 26 patients in an acute phase of aseptic meningitis was 110.6 +/- 51.1 pg/ml which was significantly (P less than 0.01) lower than the controls. These patients had a mean temperature of 101.4 +/- 1.5 degrees F which remained elevated for an average of 3.5 days. The NTLI concentrations in CSF of 23 patients in a recovery phase (after blood and CSF findings became normal with no fever) were 166.5 +/- 57.8 pg/ml, which did not differ significantly from the normal. There were no statistical correlations between the NTLI concentration in CSF and the protein concentration or total cell count in CSF. These results suggest that NTLI concentration changes during a febrile aseptic meningitis and that it may be associated with thermoregulation.

Ontogenic development of neurotensin-like immunoreactivity in the gastrointestinal tract and the influence of dietary changes in rats.

The ontogenic development of neurotensinlike immunoreactivity (NTLI) in the gastrointestinal tract was studied in three groups of male rats on different diets. Group I rats were weaned physiologically. Group II rats received only mothers milk until 25 days of age. Group III rats were fed mothers milk alone for 20 days and then switched abruptly to laboratory chow. The NTLI concentration in the gastrointestinal tract from the esophagus to the small intestine was almost the same as that in adult rats before weaning. It increased after weaning to a peak on day 20 or 25, and then decreased to the adult level. The NTLI concentration in the cecum and large intestine, however, decreased from high neonatal level, reaching the adult level on day 20 or 25, and it remained constant thereafter. Prolonged mothers milk feeding alone enhanced neurotensin production in the esophagus and postponed the physiological decrement of NTLI concentrations in the duodenum and small intestine. The sudden change from mothers milk to laboratory chow accelerated the decrement of intestinal NTLI concentrations.

Influence of diet on the development of gastrin- and somatostatin-like immunoreactivity in the stomach of rats

The effects of changes in diet on antral gastrin-like immunoreactivities and antral and corporal somatostatin-like immunoreactivities were studied in three groups of young male rats. Group 1 rats were weaned physiologically, group 2 rats received only breast milk, and group 3 rats were fed milk until 20 days of age and then were switched abruptly to laboratory chow. In group 1, antral gastrin-like immunoreactivity and somatostatin-like immunoreactivity increased gradually from 13 days of age to adults. In group 2, antral gastrin-like immunoreactivity did not increase, and antral and corporal somatostatin-like immunoreactivity increased until 20 and 25 days of age, respectively. In group 3, there were three- to fivefold increases of antral gastrin-like immunoreactivity and somatostatin-like immunoreactivity after changing to laboratory chow. Dietary changes had no effect on the concentration of corporal somatostatin-like immunoreactivity. These results suggest that the developmental patterns of gastric gastrin-like immunoreactivity and somatostatin-like immunoreactivity are closely related to diet; laboratory chow may play an important role in the development of these gut hormones.