Changes in prolactin levels with the menopause: the effects of estrogen/androgen and calcitonin treatment.

Prolactin levels were evaluated over a 2-year period in three groups of postmenopausal women: group A consisted of 35 untreated women distributed according to time since the menopause; group B consisted of 17 women on a combined estrogen/androgen preparation (Gynodian depot) intramuscularly at monthly intervals; and group C consisted of 12 women on 100 units of salmon calcitonin intranasally on alternate days and 1500 mg calcium daily. The control group (group D) consisted of 11 healthy premenopausal women. Serum prolactin, estradiol, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were measured at the onset and at 6-month intervals over 24 months. Mean serum prolactin concentrations decreased significantly during the second postmenopausal year in untreated women p = 0.0001 and p = 0.0000 after 18 and 24 months, respectively) when compared to either the levels in premenopausal women or those at the beginning of the menopause (p = 0.0007). Neither combined estrogen/androgen nor calcitonin therapy significantly influenced prolactin levels which were similar throughout the observed period. In the group on a combined estrogen/androgen preparation, physiological estradiol concentrations together with a suppression of gonadotropins during the first 6 months of therapy were achieved. In women treated with intranasal salmon calcitonin, estradiol, FSH and LH levels were unchanged. Our results show that prolactin levels decrease significantly during the second year of the menopause. Neither combined estrogen/androgen, nor salmon calcitonin therapy had any effect on serum prolactin concentrations in postmenopausal women.

The effect of intranasal salmon calcitonin on biochemical parameters of bone turnover in postmenopausal women.

This study aims to evaluate the effect of intranasal salmon calcitonin on variables of bone metabolism in 12 postmenopausal women during 24 months of treatment. A treatment regime of 100 U of intranasal salmon calcitonin on alternate days and 1500 mg daily of oral elementary calcium was applied. The control group consisted of 35 postmenopausal women distributed according to time since menopause. Biochemical and hormonal evaluations of calcium metabolism were performed at the start of treatment and after 6, 12, 18 and 24 months of treatment. Mean serum osteocalcin concentration was unchanged during the 1st year of treatment but was significantly elevated during the 2nd year (p = 0.03 and p = 0.005 after 18 and 24 months, respectively) when compared to levels at 12 months. Similar elevation of osteocalcin levels was observed in untreated women during the first 12 postmenopausal months. Mean 24-h hydroxyproline excretion decreased during the first 12 months of therapy but increased in the subsequent 6 months. The observed rise in serum osteocalcin concentration and urinary hydroxyproline excretion during the 2nd year of treatment with calcitonin was accompanied by a significant rise in serum calcitonin level. No significant differences in serum calcium, phosphorus, alkaline phosphatase or parathormone concentration, or urinary calcium excretion, were observed between treated and untreated women during the 24-month period. This study shows that 12 months' treatment with intranasal salmon calcitonin decreases bone resorption in early postmenopausal women, while bone formation remains unchanged. Longer treatment with intranasal salmon calcitonin, however, seems to be ineffective, most probably due to secondary resistance to calcitonin.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of recombinant human growth hormone on regulation of growth hormone secretion and blood glucose in insulin-dependent diabetes.

GH hypersecretion in insulin-dependent diabetes (IDDM) is well documented. Although it has recently been shown that residual insulin secretion determines the magnitude of this GH hypersecretion, the underlying mechanisms of the disorder have not yet been clarified. The 24-h GH and blood glucose profiles, insulin-like growth factor I (IGF-I) concentrations and GH responses to GRF were analyzed in 21 insulin-dependent diabetics and 4 healthy subjects before and after 7 days treatment with recombinant human GH (rhGH) (4 IU given sc at 0800 h). According to C-peptide response to glucagon IDDM patients were subdivided into C-peptide negative (CpN, n = 12) patients without endogenous pancreatic beta-cell activity and C-peptide positive (CpP, (n = 9) patients with endogenous insulin secretion. No significant difference could be observed between the mean 24-h blood glucose profile before and after rhGH treatment in any treated group. Before and on rhGH treatment the highest 24-h GH values were observed in CpN patients when compared to CpP and controls. The rhGH treatment induced a similar increase in the mean 24-h GH concentrations in all groups studied which was statistically significant only in CpP diabetics. Mean pretreatment serum IGF-I concentrations were not significantly different between CpN, CpP patients and controls. The net increase in IGF-I concentrations after rhGH treatment was however, significantly lower in CpN patients than in CpP and control subjects. GRF-induced GH response before and after rhGH treatment was significantly greater in diabetics than in controls. The response of GH to GRF in CpN diabetics was however, almost unchanged after treatment whereas it became lower in CpP diabetics and controls. The dose of 4 IU of rhGH increased significantly GH levels in diabetics with preserved beta-cell function with consequent increase in IGF-I levels and attenuation of GRF induced GH response. In contrast, the same dose of rhGH failed to induce significant increase in GH levels in diabetics without residual beta-cell activity, most probably due to already high pretreatment levels. In addition, neither increase in IGF-I levels nor suppression of GH response to GRF on rhGH treatment was observed in CpN diabetics. The results are in keeping with an important role of portal insulin in GH-induced hepatic IGF-I secretion.

The effect of the somatostatin analogue octreotide on growth hormone secretion in insulin-dependent diabetics without residual insulin secretion.

Growth hormone (GH) hypersecretion is well documented in insulin-dependent diabetes mellitus (IDDM). Somatostatin inhibits GH in acromegalics and healthy subjects although data on its inhibitory effects on high GH levels in IDDM patients are controversial. The effect of treatment with the somatostatin analogue octreotide ("Sandostatin") on GH secretion, IGF1 levels and metabolic control was investigated in insulin-dependent diabetics. Growth hormone and blood glucose were measured at hourly intervals whilst IGF-I was measured every 6 hours during the 24-h period before and after 7 days' treatment with octreotide (200 micrograms subcutaneously three times daily) in 10 C-peptide negative diabetics. Octreotide significantly reduced mean 24 h GH profile (7.2 +/- 0.7 mU/L before; 5.2 +/- 0.5 mU/L on octreotide, p less than 0.01), IGF-I levels (0.62 +/- 0.06 before; 0.47 +/- 0.05 on octreotide, p less than 0.005) mean 24 h blood glucose (14.4 +/- 0.5 mmol/L before; 12.6 +/- 0.4 mmol/L on octreotide, p less than 0.001) and daily insulin requirements (44.8 +/- 3.0 IU before; 37.2 +/- 3.0 IU on octreotide, p less than 0.02). The shape of 24 h GH profile curve changed significantly on octreotide treatment (p less than 0.05) when it consisted of three nadirs and three peaks closely linked with the time of octreotide administration. Moderate (abdominal discomfort) to severe hypoglycaemia) transient side effects have been observed in all treated patients. The results of this study showed that short-term treatment with octreotide given s. c. every eight hours modulates the pattern of GH secretion in C-peptide negative insulin-dependent patients.(ABSTRACT TRUNCATED AT 250 WORDS)