It has been recently shown that acute hypercalcemia increases the release of growth hormone in man. We investigated the effect of intravenous administration of calcium gluconate on the levels of growth hormone, during OGTT, in 8 non-obese subjects. When an OGTT was performed with the addition of Lv. normal saline, no significant increase of serum growth hormone concentration was seen. However i.v. administration of calcium gluconate with OGTT induced a significant increase of growth hormone at 120 and 180 minutes (from 1.4 ± 0.8 ng/ml to 13.4 ± 5.7 ng/ml and 9.3 ± 2.1 ng/ml respectively). The growth hormone response to acute hypercalcemia was not abolished by a simultaneous OGTT, showing that the stimulatory effect of high levels of plasma calcium overcomes the inhibitory action of glucose.

No abstract

Unlike the findings in animal studies, in which a decline in progesterone levels is clearly associated with the onset of labor, investigation of progesterone levels among human parturients has resulted in controversy. This study was designed to address the issue and evaluate labor-onset related changes of estradiol-progesterone (E2-P) concentration in fetal scalp serum, umbilical vein serum and in the peripheral maternal serum. Seven women in spontaneous labor, were compared to 7 women in whom labor was induced. Our results reveal a significant decrease in the maternal serum P concentration when spontaneous labor is taking place (120.6 +/- 24.5 mg/ml verus 177.3 +/- 61.4 mg/ml, p < 0.05). Significant change in the ratio of the fetal scalp to the maternal serum E2/P ratio in women at spontaneous labor versus induced labor is also shown. We could not demonstrate any changes in the E2 levels in relation to labor. We conclude that the onset of labor in human pregnancy is most probably preceded by local changes in the levels of P and ratio of P to E2. These changes may play an important regulatory role in onset of labor.

IntroduetionGlucagon, besides its known metabolie actions, has shown interesting stimulatory effects on several polypeptide hormones such as insulin (Samols, Marri and Marks 1966), growth hormone (Mitchel/, Byrne, Sanchez and Sawin 1970, Wieland, HaI/-berg and Zorn 1973, Spathis, Bloom, Jeffcoate, Mil/er, Kurtz, Pyassena, Smith and Naba"o 1974 and ACTH (Spathis, Bloom, Jeffcoate, Mil/er, Kurtz, Pyassena, Smith and Naba"o 1974).No effect was found on the luteinizing hormone (LH) when glucagon was administered intravenously (Eddy, Jones and Hirsch 1970).The method of administration of glucagon is very important. When given intravenously many workers did not observe a stimulation of the several hormones mentioned (Danforth and Rosenfeld 1970, Jones andHirsch 1970), while administration of glucagon subcutaneously or even better, intramuscularly, produced a very good stimulation (Gi/boa, R osen berg, Hertzeanu, Langstein 1973, Wanderschueren, Lodeweyckx, Wolter, Malvaux, Eggermont and Eckeis 1974).We therefore investigated the effect of glucagon on plasma LH after intramuscular administration. Material and MethodsGlucagon 0.03 mg/kg body weight was administered to 13 healthy subjects, males and females. In one separate patient the glucagon stimulation was done after a test with LHRH showed good LH reserve. The level of plasma LH was estimated after intramuscular injection of normal saline in 2 subjects, as controls. Blood was taken at 0, 1, 2 and 3 hours after the injection, plasma was immediately separated and frozen until examined. LH was estimated by RIA ("Sorin" kit) and the results expressed in milliunits/ml (2nd IRP). Table 1. Plasma LH (mu/ml) in 11 subjects stimulated with glucagon 0.03 mg/kg i.m. and in 2 control subjects, after saline injection Results and Comments